henan seasun heavy industry machinery co., ltd

henan seasun heavy industry machinery co., ltd

Introduction of Mobile crushing plant: Mobile crushing plant, a new designed rock crushing & screening plant, is flexible, convenient and strong in mobility, so it can save a large construction capital and relocation. Raw Materials can be broken at the local place without being transported again, and also can be moved with the further exploitation of the raw material, which saves a large number of transportation cost. HeNan shisheng corporation specializes in producing crusher, screen, transportation, other rock breaking, minerial processing equipment. Integrated series of mobile crushing plant can be used independently, can also be for the types of customer material in the process, product requirements, provide a more flexible process configuration to meet mobile crusher, mobile screening and other requirements for user, so that the resulting organization,a more direct and effective logistics and transshipment costs to maximize the lower.Products have been optimized and enhanced design, higher strength, better performance, more compact structure. Advantages of Mobile crushing plant: 1.PE Series high performance jaw crushers 2.Incorporated the feeder and vibrating screen into the crusher 3.Everything on board: crusher, feeders, screens, belts and power installations 4.Quick road transportation thanks to king pin arrangement 5.Installation support legs on the trackquick to set-up 6.Electric motor and control cabinet are on the same truck Technical parameters of mobile crushing plant: PPjaw portable crusher PP600 PP750 PP900 PP1060 PP1200 PP1300 Shipping size Long 8600 9600 11097 13300 15800 9460 Wide 2520 2520 3759 2900 2900 2743 High 3770 3500 3500 4440 4500 3988 Weight 15240 22000 32270 57880 98000 25220 Alex load 10121 14500 21380 38430 64000 14730 Tractor weight 5119 7500 10890 19450 34000 10490 Jaw crusher Type PE400*600 PE500*750 PE600*900 PE750*1060 PE900*1200 PE300*1300 Material inlet 400*600 500*750 600*900 750*1060 900*1200 300*1300 Adjusting range of discharge hole 40-100 50-100 65-180 80-180 95-225 20-90 Capacity(m3/h) 10-35 25-60 30-85 70-150 100-240 10-65 Vibrating feeder Type 8030 9638 1149 1352 8030 Capacity of material cabin 3 4 7 10 10 3 Width of material cabin 2200 2500 3000 3000 3000 2200 Belt conveyor type B500*6 B650*7 B800*8 B1000*11 B1200*13 B800*7

Mobile crushing plant, a new designed rock crushing & screening plant, is flexible, convenient and strong in mobility, so it can save a large construction capital and relocation. Raw Materials can be broken at the local place without being transported again, and also can be moved with the further exploitation of the raw material, which saves a large number of transportation cost. HeNan shisheng corporation specializes in producing crusher, screen, transportation, other rock breaking, minerial processing equipment.

Integrated series of mobile crushing plant can be used independently, can also be for the types of customer material in the process, product requirements, provide a more flexible process configuration to meet mobile crusher, mobile screening and other requirements for user, so that the resulting organization,a more direct and effective logistics and transshipment costs to maximize the lower.Products have been optimized and enhanced design, higher strength, better performance, more compact structure.

Advantages of Mobile crushing plant: 1.PE Series high performance jaw crushers 2.Incorporated the feeder and vibrating screen into the crusher 3.Everything on board: crusher, feeders, screens, belts and power installations 4.Quick road transportation thanks to king pin arrangement 5.Installation support legs on the trackquick to set-up 6.Electric motor and control cabinet are on the same truck

metso global website - metso

metso global website - metso

The combination of Metso Minerals and Outotec has been completed and the new company, Metso Outotec, was established on July 1, 2020. At the same time, Metso Flow Control became a separately listed independent company and started its journey under the name of Neles.

The combination of Metso Minerals and Outotec is completed and the new company, Metso Outotec, started its journey.Metso Outotec is a frontrunner in sustainable minerals processing technologies, end-to-end solutions and services globally.The company helps aggregates, mining, metals refining and recycling customers improve efficiency, productivity and reduce risks.

Metso Flow Control has become a separately listed independent company called Neles. Neles is a flow control solutions and services provider for oil and gas refining, pulp, paper and the bioproducts industry, chemicals, and other process industries.The company's valves and valve automation technologies are known for quality, reliability and highest safety.

symons cone crusher

symons cone crusher

For finer crushing or reduction a Symonscone crusher the norm. Symons are commonly used for secondary, tertiary or quaternary crushing. They do this by a different chamber design which is flatter and by operating at about twice the rotational speed of a primary type gyratory crusher.

One of the first cone crushers had a direct drive vertical motor mounted above the spider with the drive shaft passing through the hollow bored main shaft. With relatively high speeds of 480 to 580 rpm and small eccentric throw, the machine produced a uniform produce with minimum fines.There are numerous Symonscone crusher manufacturers of modern crushers each promoting some unique aspect.

The Allis Chalmers Hydrocone selling point is its adjustability and tramp protection through a hydraulic support system for the headcentre. By merely adjusting the oil reservoir below the head centre the crusher setting can be changed while in full operation. Tramp metal causes a surge of pressure in this hydraulic system which is absorbed through relief valves and gas-bladder-filled accumulator bottles which allow the headcentre to momentarily drop and return to its normal operating position when the tramp has fallen through.

The Symons or Rexnord spring cone crusher is adjusted by spinning the bowl up or down manually or through hydraulic rams. A series of powerful springs give the necessary tramp protection. Several other manufacturers produce similar types and sizes of crushers but all follow the basic types described.

When the Symons brothers Invented the cone crusher, they employed the principle wherein the length of the crushing stroke was related to the free fall of material by gravity. This permitted the material being crushed to fall vertically in the crushing chamber; and in effect, caused the particles to be crushed in a series of steps or stages as the particles got smaller due to the crushing action. This also helps to reduce the rate of wear of the liners since the sliding motion of the particles is minimized.

Recognizing that the Symons principle of crushing is the most efficient means of ore and aggregate reduction in hard rock applications, the engineers used this same principle in the design on the hydrocone.

Versatility in the form of having the ability to perform in a wide range of applications without the need for a change in major assemblies was another objective in the design. Ease of maintenance and remote setting capability also were part of the design parameters the market requires.

There is no startling revelation to the fact that the mining industry as a whole is generally moving toward the use of larger equipment to process ores in quantities far greater than what was even considered a decade ago. Trucks and shovels have led the way in extra large machines and many other manufacturers have followed suit in the development of so-called supers in their line of equipment.

In order to keep pace with the industry, crusher manufacturers have also enlarged the size of their equipment. There is now on the market, a Gyratory crusher capable of accepting a 72 diameter piece of ore. Primary jaw crushers have also increased in size. It is inevitable, therefore, that larger secondary cone crushers would also be required to complement the other equipment used to process these large quantities of ore. This super-size secondary cone crusher is the SYMONS 10 Ft. Cone Crusher.

Until 1973, the largest cone crusher built was the 7 Ft. Extra Heavy Duty crusher, which is currently used in the majority of the mining operations throughout the world. The 10 Ft. crusher, when compared to the 7 Ft. Extra Heavy Duty Crusher, is approximately 1 times larger in physical dimensions; three times heavier; will accept a maximum feed size which is approximately twice as large; and will crush at approximately 2 times the rate of the 7 Ft. machine at identical closed side settings. It will be the largest cone crusher built in the world.

The conclusions of this investigation were all positive the crusher could be built and at a cost that would be in line with its size and capacity and also with other size crushers. After that preliminary study, the project became dormant for several years.

The project was reactivated and this time general assembly drawings were made which incorporated many improvements in the crusher such as pneumatic cylinders in place of the conventional, springs for tramp iron release, a two-piece main frame a dynamically balanced design of the internal moving parts of the crusher, and an automatic clearing and adjusting mechanism for the crusher. At this stage of development we felt we were ready to build a 10 Ft. crusher for any mine that was willing to try one. Unfortunately, the conservative posture of the mining industry did not exactly coincide with our sales plans. This, added to the popularity of the autogenous mill concept at the time, led to another lull in the 10 Ft. development program.

The project was reactivated again in 1970, this time primarily at the request of one of the large Minnesota Iron Range mining companies. We then undertook a comprehensive market research study to determine if there was a need for this size crusher by the mining industry in general, rather than just the iron ore industry. We talked not only to the iron ore people but to the copper people and persons connected with the other metallic ores as well. The acceptability of this large crusher was also discussed with the aggregate industry. After interviews with many of the major mining companies, the decision was made to complete the entire engineering phase of the development program and to actively solicit a customer for this new crusher. We spent approximately $85,000 on engineering work and tests on the gamble that we could find a customer. I speak of a gamble because during our market research study we continually were told my company would be very interested in buying a 10 Ft. crusher, but only after we have seen one in operation.

The actual building and test of the first prototype unit without a firm commitment for a sale was an economic impossibility. We were now at the point where we needed to sell at least one unit in order to prove not only the mechanical reliability of the machine, but the economic justification for its purchase as well. Needless to say, when the order for two SYMONS 10 Ft. cone crushers was received, we felt we were now on the way toward completion of the development program.

Perhaps at this point it might be apropos to examine the crusher itself. It will stand 15-6 above its foundation, the overall height will be 19-4-. At its greatest diameter, in the area of the adjustment ring, it will be approximately 17-6. It will weigh approximately 550,000 lbs. Under normal crushing conditions, the crusher will be connected to a 700 HP motor. A 50 ton. overhead crane is required to perform routine maintenance on this crusher.

The main shaft assembly will weigh approximately 92,000 lbs. and the bowl assembly approximately 95,000 lbs. The mantle and bowl liner, cast from manganese steel, will weigh approximately 13,000 lbs. and 25,000 lbs. respectively.

The throughput capacity of the Standard will be approximately 1300 TPH at a 1 closed side setting and 3000 TPH at a 2- closed side setting. The throughput capacity of the SHORT HEAD will be approximately 800 TPH at closed side setting and 1450 TPH at a 9/16 closed side setting.

Persons familiar with the design of a conventional 7 Ft. SYMONS cone crusher will recognize that the design of the 10 Ft. is quite similar to it. As a matter of fact, we like to say that the design of the 10 Ft. is evolutionary rather than revolutionary, because all the reliable features of the SYMONS cone crusher were retained and the only changes that were made were those that added to the convenience of the operator, such as automatic clearing and automatic adjustment. From a mechanical point of view the stresses generated due to crushing loads are less in the 10 Ft. crusher than in the existing 7 Ft. Extra Heavy Duty cone.

One of our senior engineers who has long since retired told me that he had the occasion many years ago to make a presentation of a newly designed crusher to a prospective customer. He carefully prepared a rather detailed description of the crusher which included all the features that his new machine had when compared to the customers existing machine. The presentation itself took about one hour and after that period the customer leaned back in his chair and said, Thats all well and good, but will it crush rock? In effect, the customer was; saying that all the features in the world were of no use to him if the crusher did not perform its basic function to crush rock and ultimately make profits for the owner. Using todays financial terminology he was asking the engineer to economically cost justify the purchase of the crusher.

The working day of the contemporary manager or project engineer evolves around making decisions to economically justify a piece of equipment or a new operation. In our development program of the 10 Ft. cone crusher, we felt that the economic justification, from the customers point of view, was just as important to develop as the engineering aspects of the program. So we developed a three-part program to examine the economics of installing a 10 Ft. crusher. First we talked in wide generalities concerning the use of a 10 Ft. crusher. Secondly, we discussed the ramifications of using a 10 Ft. crusher versus 7 Ft. crushers in a completely new plant being considered for the future. Thirdly, we examined how a 10 Ft. crusher could be used to its best advantage in a plant that is being expanded.

The first consideration was the economic generalities of installing the crusher, or more specifically, what questions regarding the installation are pertinent to every crushing plant. Usually, the initial comparison which is made between a 7 Ft. crusher and a 10 Ft. crusher is that of price versus capacity. Theoretically, the capacity of a 10 Ft. crusher is 2 times that of a 7 Ft. while the selling price is approximately 3 times that of the 7 Ft. On that basis alone, it would appear that the 10 Ft. could not be justified. However, this is an incomplete picture. Recent cost estimates show that considerable savings are realized when the entire physical plant structure is considered. Because fewer machines are required to crush an equivalent amount of ore, the size of the buildings can be reduced, thereby decreasing the capital investment of buildings and allied equipment used as auxiliaries for the crusher.

Total manpower requirements to operate and maintain the plant is another of the generalities which were considered. Fewer crushers normally require less personnel to operate and perform maintenance, Manpower requirements obviously play a large part in the profitability of a plant. Therefore, it follows that using a 10 Ft. in place of multiple 7 Ft. units should be more profitable from the standpoint of manpower. We should, however, clarify one point regarding normal maintenance of the 10 Ft. crusher which is commonly misunderstood; namely, the periodic changeout of manganese liners in the crusher. The normal time period between manganese changes would not be significantly different between the 7 Ft. and a 10 Ft. because the wear rate, that is, the pounds of liner worn away per ton of ore crushed, will remain the same. Consequently, if a set of liners in a 7 Ft. crusher, lasted six weeks, a 10 Ft. crusher in the same operation would also last approximately six weeks. However, since the total amount of ore crushed will be greater, the maintenance costs per liner changeout will be less on the 10 Ft. crusher.

Another point for consideration is that the 10 Ft., cone crusher is a secondary crusher and normally would be fed with the product of a gyratory crusher. Since the 10 Ft. can accept a larger feed than a 7 Ft. crusher, it is possible to increase the open side setting of a gyratory crusher, thereby, allowing a greater volume of feed to pass through the crusher. Because of this, it is conceivable that a smaller primary crusher could be used in order to obtain a given quantity of ore.

A good salesman could expound on a multitude of ideas for using 10 Ft. crushers in place of 7 Ft. crushers in a new plant, but in the final analysis, the deciding factor as to whether or not the 10 Ft. crushers should be used will be the anticipated over-all plant capacity. Several studies have indicated that as a general rule of thumb the break even point for using 10 Ft. crushers in place of 7 Ft. crushers is a plant which will have an overall ore treatment capacity of approximately 40,000 TPD or approximately 8,000,000 TPY. Anything less than that figure should indicate the use of conventional 7 Ft. crushers. Obviously a small four stage crushing plant in which the third stage crusher was a 7 Ft. Standard and the fourth stage consisted of two 7 Ft. SHORT HEAD cone crushers, would not improve economically by the use of one 10 Ft. Standard cone crusher and one 10 Ft. SHORT HEAD cone crusher in place of the 7 Ft. crushers.

A study was made which considered a plant to be built using three different approaches of a conventional crushing-grinding operation. The plant which was being considered would be crushing taconite similar to that found in the Iron Range. The end product of the crushing was 5/8 rod mill feed and in this example the plant capacity was to be approximately 13.5 million TPY of ore processed to eventually produce approximately 4 million TPY of iron ore pellets. The study arbitrarily chose a four-year period of operation so that operating costs would be included and also because a four-year period is the usual comparison basis for calculating return on investment. In this example the primary crusher as well as the fine crushing plant would be operated fourteen shifts per week.

In our economic analysis of the 10 Ft. crusher development program, we also studied how this crusher could be used to best advantage when planning expansion of an existing plant. Before delving into the actual dollars and cents of several variations of expansion plans, several preliminary questions must be answered in the affirmative:

Since each plant is unique, the relative merits of the 10 Ft. crusher must be examined on an individual plant basis. Again, as a general rule of thumb, it has been found that the most benefit can be achieved in those plants which presently contain a four-stage crushing plant in which the first two stages of crushing are gyratory crushers. Studies have shown that converting the second stage gyratory crusher to a 10 Ft. Standard crusher shows most potential because the major auxiliaries required for the crusher, such as crane, conveyors, etc., are already large enough to accommodate the increased capacity of the 10 Ft.

As one possible solution, we suggested that the two 30 x 70 secondary gyratory crushers be replaced by two 10 Ft. Standard cones. These crushers could then send approximately 3600 TPH of minus 3 material to the fine crushing plant. The two existing 7 Ft. Standard crushers could be converted easily to SHORT HEAD crushers and two new 7 Ft. SHORT HEAD crushers added to the existing vacant foundations.

In Summary, we feel that the Symons cone crusher has a very definite place in the future of the mining industry and we intend to move steadily ahead with its progress. However, we have learned a few lessons along the way.

Initially, the development of these super size machines is an extremely expensive proposition. We know that if our company alone, attempted to completely design, manufacture, erect, and test a machine in this size range, it would severely tax our financial resources.

We found that super size equipment also presents some problems for our manufacturing facilities. The manufacture of one of these units puts a large dent into the production schedule of many of the smaller conventional units. In our enthusiasm to build a bigger newer machine, we continually remind ourselves that the smaller conventional units are still our bread and butter units.

On the positive side, we found that our reputation as a crusher manufacturer was enhanced because of what our customers refer to as progressive thinking. We listened to the suggestions of the mining industry in attempting to give them what they wanted.

Perhaps you will allow me to close with a bit of philosophizing from a manufacturers point of view. The 10 Ft. crusher is here ready to go into operation. Where do we go from here? A 15 Ft. cone crusher? A 20 Ft. cone crusher? Who knows? We do know that we have reached the financial limit of a development program on a machine of this size. We also know that as the size of a machine grows larger, the developmental and manufacturing risks grow larger along with it and any allowable margin for error must be minimized. We, like you, are in business to make a profit. Since larger crushers usually mean a fewer number of crushers, we must examine the profit picture from aspects of the sale. I think I speak for other manufacturers as well when I say that bigness in machines reflects bigness in development costs as well. If the mining industry wants still larger equipment in the future, the industry should prepare itself to contribute to the development program of those machines.

A multi-cylinderHydraulic Cone Crusher, theHydrocone Cone Crushercan be used in either the second or third stage of crushing by merely changing liners and adaptors.It can produce the full product range that the combination of a comparable sized Standard and Short Head can produce. It makes the machine much more versatile. It allows for much more standardization. The value of this feature is one where spare parts investment in the form of major assemblies is minimized.

All operator controls are conveniently mounted on a remote control console to eliminate the need for an operator to approach the crusher during operation.Over a period of years we have developed a unique engineering knowledge about the effects of cone crusher design parameters such as speed, throw and cavity design on crusher productivity.

Each Hydrocone Cone Crusher features dual function hydraulic cylinders that provide overload protection and a safe and fast way to clear a jammed cavity. Should the crusher become plugged, the operator merely pushes levers on the remote control console to clear the cavity.

It can produce the full product range that the combination of a comparable sized Standard and Short Head can produce. It makes the machine much more versatile. It allows for much more standardization. The value of this feature is one where spare parts investment in the form of major assemblies is minimized.

All operator controls are conveniently mounted on a remote control console to eliminate the need for an operator to approach the crusher during operation.Over a period of years we have developed a unique engineering knowledge about the effects of cone crusher design parameters such as speed, throw and cavity design on crusher productivity.

Each Hydrocone Cone Crusher features dual function hydraulic cylinders that provide overload protection and a safe and fast way to clear a jammed cavity. Should the crusher become plugged, the operator merely pushes levers on the remote control console to clear the cavity.

TheHydraulic Cone Crusheruses hydraulic tramp release cylinders and accumulators to hold the adjustment ring against the main frame seat. There is only one angular surface between the main frame and the adjustment ring which also has a radial contact point in the lowermost area. When a piece of tramp goes through the crusher, the oil is forced into the accumulators allowing the adjustment ring to raise and pass the tramp.

The tramp release cylinders are secured to the adjustment ring and the lower portion of the main frame through clevises. This allows the crushing forces to be transferred directly from the frame arm locations to the adjustment ring. This relieves the main frame shell and upper flange from carrying heavy loads.

The Hydraulic Cone Crusher is equipped with hydraulic clearing. The tramp release cylinders which hold the adjustment ring in place are double acting cylinders. These cylinders can be pressurized in the opposite direction, after the clamping pressure has been released, to raise the adjustment ring and bowl assembly for clearing; only the weight of the adjustment ring, clamp ring, and bowl assembly, plus any residual material in the bowl hopper raises.

find bobcat attachments and implements - bobcat company

find bobcat attachments and implements - bobcat company

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cone crusher | henan deya machinery co., ltd

cone crusher | henan deya machinery co., ltd

Symons cone crusher (spring cone crusher) can crush materials of above medium hardness. And it is widely used in metallurgy, building, hydropower, transportation, chemical industry, etc. When used with jaw crusher, it can be used as secondary, tertiary or quaternary crushing. Generally speaking, the standard type of Symons cone crusher is applied to medium crushing. The medium type is applied to fine crushing. The short head type is applied to coarse fine crushing. As casting steel technique is adopted, the machine has good rigidity and large high strength(via wikipedia).

ijmmme - flotation of lithium ores to obtain high-grade li2o concentrates. are there any mineralogical limitations?

ijmmme - flotation of lithium ores to obtain high-grade li2o concentrates. are there any mineralogical limitations?

1Laboratrio Nacional de Energia e Geologia Rua da Amieira, Apartado 1089, S. Mamede de Infesta, Portugal [email protected]; [email protected]; [email protected] 2Institute of Earth Sciences, Porto Pole; Department of Geosciences, Environment and Spatial Planning of the Faculty of Sciences of the University of Porto Rua do Campo Alegre, 4169-007 Porto, Portugal [email protected]; [email protected]; [email protected]

Abstract - The current lithium demand for batteries in general and namely for the electrical vehicle, awakened the attention for mineral processing of lithium ores. The largest lithium reserves are in brines from western South America and in pegmatites. Throughout Europe it is possible to identify several lithium deposits, namely in granitic pegmatites. An efficient mineral processing approach could be the key for an economically viable mining project. This work addresses a mineral processing study by froth flotation of samples collected in two European lithium ore pegmatites deposits - Lntt (Finland) and Gonalo (Portugal) and aims at paying attention to some mineralogical features that can decrease the mineral processing efficiency and consequently the upgrading of the Li2O concentrates. In the case of Lntt, spodumene is the main lithium mineral and a grade of 5.20 % Li2O is the maximum obtained in the concentrates, whilst lepidolite is the lithium-bearing mineral in Gonalo and that can be concentrated by froth flotation up to 4.50 % Li2O. Taking into consideration the Li2O content of both Lntt spodumene and Gonalo lepidolite, respectively 7.0 and 5.58 % Li2O, higher concentrate grades would be expected. In both studied cases, very fine quartz and albite inclusions locked in lithium silicates were identified justifying the existence of a limitation for the processing technology. The mineral processing of the two pegmatites revealed the difficulty of producing Li2O close to the stoichiometry of the spodumene and lepidolite in either of these two ores.

Copyright 2019 Authors This is an Open Access article published under the Creative Commons Attribution License terms. Unrestricted use, distribution, and reproduction in any medium are permitted, provided the original work is properly cited.

The present tendency for the development of portable devices and the application of batteries as power sources in electric cars and tools are creating an extra demand for lithium, being one of the most important strategic raw materials for many industries [2]. Batteries are considered the most suitable option for conservation, storage, and transmission of renewable energy. The capability of storing a large amount of energy within a given volume-to-mass ratio in a short period of time is considered the most critical characteristic of any battery [3, 4] and the lithium ion batteries are considered the most promising way to capture energy [5]. Due to that fact, the application of lithium ion batteries in the rechargeable batteries technology would be essential for the industrial growth, to reduce the environmental constraints linked to the traditional energy transmission technologies, to enhance the energy security, and to improve the daily life conditions [6, 7]. Lithium also finds application in other industries, such as ceramics, glass, primary aluminium production, pharmaceutical, manufacture of lubricants and greases, synthesis of vitamin A and organic compounds, among others [8, 9, 10, 11].

In 2016, the countries with the largest lithium reserves worldwide were Chile (7.5 Mt), China (3.2 Mt), Argentina (2 Mt), Australia (1.6 Mt), Brazil (0.48 Mt), Portugal (0.06 Mt), United States (0.038 Mt) and Zimbabwe (0.023 Mt). For the same considered year, the major countries in worldwide lithium mine production were Australia (14,300 t), Chile (12,000 t), Argentina (5,700 t), China (2,000 t), Zimbabwe (900 t), Portugal (200 t) and Brazil (200 t) (data in metric tons of lithium content) [12].

The main sources for lithium are brines and magmatic rocks rich in lithium silicate minerals and/or phosphates. The most important rock deposits of lithium are granitic pegmatites and greisens. It has been estimated an average lithium content on Earths upper continental crust of 21 ppm [13], included in more than 20 minerals. However, just some of them occur in magmatic crystalline rocks and have commercial/industrial potential lepidolite, spodumene, petalite, amblygonite-montebrasite and zinnwaldite [2, 14].

Lithium is supplied to industry in the form of lithium carbonate, sulfate, hydroxide, chloride, bromide, and butyllithium [15]. It is crucial to determine accurate processes to obtain high-lithium grade concentrates prior to the development of new lithium-based technologies. Therefore, it is imperative to find mineral processing strategies that maximize the lithium recovery and allow for the achievement of valuable lithium-rich concentrates. Usually, the enrichment process starts with the crushing and grinding steps to attain lithium minerals liberation and, at the same time, adjusting the size of particles for the concentration processes [16, 17]. The global challenge for lithium pegmatites is to award the label of green industry when reaching the level of almost zero waste mining by also producing quartz and low iron feldspar. Optical sorting and heavy liquid separation could be applied as pre-concentration stages, while flotation could be applied as the final concentration step and gravity separation used to recover other secondary minerals [18, 19]. Froth flotation has become the most important and efficient method for lithium ores processing [20]. Previous studies showed the possibility of obtaining high-lithium grade concentrates by froth flotation from Portuguese ores, as are the cases of amblygonite (Argemela deposit) and spodumene (Barroso) assaying values close to the stoichiometry of the respective minerals [18, 21]. Furthermore, in neighbouring Galicia (Spain), an attempt to optimize the flotation of spodumene from Vilatuxe pegmatite, district of Pontevedra, was successfully carried out producing concentrates of about 6.5 % Li2O [22].

Under the scope of FAME (Flexible and Mobile Economic Processing Technologies) H2020 project, which focused on improving mineral processing technologies for the recovery of valuable materials from low grade European ores, the feasibility of froth flotation of lithium silicates from pegmatites to produce high-grade Li2O concentrates was investigated. For that purpose, samples from two lithium pegmatites, a spodumene-rich from Lntt (Finland) and a lepidolite-rich from Gonalo (Portugal), were selected from the target ores considered on the FAME project. This paper reports a detailed mineralogical study as a crucial step for the interpretation of some results experimentally obtained.

The pegmatite deposit of Lntt, Western Finland, is located at Ullava, about 60 km southeast of Kokkola town. The Lntt pegmatite occurs in the Kaustinen lithium province that covers roughly 500 km2 in the Paleoproterozoic Pohjanmaa Schist Belt (1.92 Ga), which forms a 350 km long and 70 km wide arc-shaped belt between the Central Finland Granite Complex in the East and the Vaasa Migmatite Complex in the West (Figure 1). The pegmatites are younger than the 1.89-1.88 Ga peak of regional metamorphism, have an age of 1.79 Ga (U-Pb columbite age) and crosscut Svecofennian 1.951.88 Ga supracrustal rocks, which are composed of schists with some intercalations of sulphide-bearing black schists and volcanic metasediments. The metamorphic grade in the Pohjanmaa Schist Belt varies from low amphibolite facies in the eastern part to high amphibolite facies towards the Vaasa Granite complex [23]. At least, 16 separate albite-spodumene-pegmatite occurrences are known in the Kaustinen lithium province [24].

The Lntt deposit consists of two main pegmatite dikes of a maximum thickness of about 10 m together with some nearby smaller parallel dykes at the contact between meta-volcanic rocks and schists. The dykes run NW-SE, and are almost vertical or dipping 70 to SE. The thickness of the overburden in the area averages 4 m, varying between nearly 0 and 7 m.

The Lntt pegmatites can be classified as belonging to the REL-Li subclass, albite-spodumene type of the LCT (Li, Cs, Ta) pegmatite family [25] and constitute a typical example of a homogenous albite-spodumene pegmatite (56 % albite, 25 % quartz and 16 % spodumene). Columbite, cassiterite, beryl, muscovite, K-feldspar, garnet, apatite, zircon, tourmaline, lithiophilite-triphylite, topaz, gahnite spinel, calcite, pyrite, arsenopyrite, sphalerite, and bismuthinite are also present [26].

The major lithium ore is spodumene that occurs as large crystals of 4-10 cm, but can reach up to 30 cm, and is mainly light green, partly light pink or red. The total mineral resources are 1.3 Mt @ 1.08 wt% Li2O with a cut-off value at 0.50 wt% Li2O [27].

The Gonalo pegmatite district is located in Central Portugal, approximately 20 km south of Guarda town, not far from the eastern border of Spain, and covers an area of 100 km2 of the Central Iberian Zone in the western extreme of the European Variscan Belt. The pegmatites are granitic in composition occurring as veins cutting a synorogenic Variscan coarse-grained porphyritic biotite>muscovite granite (Guarda granite) with 304.13.9 Ma [29] (Figure 2).

The majority of the veins run E-W to ESE-WNW slopping 20 to 30 E, up to 3.5 m thickness and corresponding to an intimate association of rocks with pegmatitic and aplitic texture that, from now on, will be referred to as pegmatite sills.

The lithium-rich pegmatite sills can be macroscopically distinguished by their typical violet colour due to the presence of lepidolite. The pegmatitic facies is characterized by lepidolite, albite, Li-muscovite, quartz, and K-feldspar as major minerals, and montebrasite, topaz, cassiterite, columbite-tantalite, beryl, petalite, and zircon as minor minerals. The aplitic facies is characterized by a sodolithic composition with lepidolite, albite, montebrasite, and quartz as major minerals; some muscovite, topaz, cassiterite, and columbite-tantalite can also occur [30, 31]. In both facies, secondary phosphates are also present, resulting from late alteration processes. Petalite is altered to kaolinite, cookeite, pollucite, and illite/smectite in late episodes of the pegmatite history.

The Gonalo pegmatite sills exhibit mineralogical and chemical features typical of peraluminous, Li- and P-bearing Rare Element (REL) pegmatites, suggesting a model of crystallization in successive steps where concentration in fluxing agents (F, Li, P, B, etc.) was progressively enhanced to saturation with the crystallization of montebrasite and lepidolite [31]. The Gonalo pegmatite can be classified as belonging to the REL-Li subclass, complex lepidolite type of the LCT pegmatite family [25].

Lepidolite is the most abundant lithium ore and occurs in both facies with different grain sizes. In the first case, it occurs mainly as medium to coarse-grained (> 500 m), whereas in the aplitic unit it frequently forms fine-grained (250-60 m) to very fine-grained ( 60 m) aggregates.

Zinnwaldite is present as result of the biotite metasomatic alteration in the host coarse-grained porphyritic biotite>muscovite granite located in the contact with the pegmatite sills. As petalite and minor Li- and P-bearing minerals, such as montebrasite and zinnwaldite, are present, the lithium content in the bulk samples does not correspond only to the lithium content of lepidolite.

The inferred mineral resource estimate is of 1.5 Mt @ 1.1 % Li2O; this is a minimum value, because only lithium-rich pegmatites and a maximum quarry front of 10 m were considered for this estimation. Therefore, it is an appraisal that regards only the superficial part of the ore deposit [32].

In this study samples of pegmatites from the Lntt spodumene deposit (Finland) and from the Gonalo lepidolite deposit (Portugal) were studied. The same comminution diagram was applied to all samples to produce material with suitable size for froth flotation (Figure 3). Samples were primarily crushed in a jaw crusher (single toggle 5x 6, 4 kW, 325-375 rpm, Denver) and in a cone crusher, followed by a rod mill. Figure 4 shows the particle size distribution (PSD) of both samples after the comminution. All material is below 425 m. It can be seen that almost 30 % of the sample mass is below 53 m, which must be removed before flotation, since the presence of fine particles reduces flotation efficiency. Table 1 shows the main size parameters and Li2O grades of the studied samples.

As mentioned before, froth flotation has become the most important and efficient method for lithium mineral processing [21], consequently it was the method applied to concentrate both lithium-rich pegmatites. Figure 5 presents the flotation flow sheet developed: a previous desliming stage is crucial for slimes removal, followed by three flotation stages, starting with a rougher stage. The rougher concentrate (RC) was upgraded in a cleaning stage, that produced a final clean concentrate (CC) and a middling product with high-lithium content (CT). A scavenger stage was applied to the rougher tailings (RT) to produce the final tailings (ST) and a low-lithium minerals middling product with low-lithium content (SC). Different flotation tests were carried out using distinct chemical reagents. Experimental work was conducted following reagent strategies mentioned by different authors [18, 33, 34, 35]. In the case of Lntt ore (spodumene pegmatite) tests were performed at room temperature, using two different collectors (Test A Oleic acid; Test B Fatty acid Aero 704 from Solvay). An optimal pH=8.8 was maintained using NaOH. The collector was then added in two stages, at dosages of 750 g/t to the rougher and 370 g/t to the scavenger, both emulsified with fuel oil (3 kg/t). The conditioning time was 5 minutes for each stage. In the case of Gonalo lepidolite, pH was maintained at 3 as widely referred in the literature and the collector Flotigam EDA (from Clariant) was added at a dosage of 200 g/t in the first conditioning stage and 100 g/t in the second one, both conditioned for 3 minutes. Froth flotation tests were conducted in a Leeds open-top laboratory flotation machine with a 3.0 L cell, at an impeller speed of 1000 rpm and an air flow rate of 7.5 L/min. These reported tests were chosen among others, carried out to assess the feasibility of froth flotation to produce Li2O concentrates.

Concentrate grades are influenced by the reagent strategy. However, as flotation is a time dependent process, in the first moments of the flotation kinetics, it is usual to obtain high-grade concentrates close to the theoretical Li2O content of each mineral, because well-liberated particles of lepidolite or spodumene are the first to float. In the reported cases, high Li2O grades were never obtained, even in the beginning of the process, meaning that floated particles, although apparently well-liberated, would not be of pure lepidolite or spodumene. These cases were considered good examples for the development of a joint research between mineralogy and technology. Chemical assays of the flotation products were determined by atomic absorption spectrometry (UNICAM-M SERIES). These tests are part of an extensive experimental program, developed in the framework of FAME project, that included analysing the influence of variables such as pH, collector type and dosage, particle size distribution, pulp density and residence time.

The mineralogical study of samples from both pegmatites was carried out using optical microscopy, scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) analyses and Raman microspectroscopy. Petrographic analyses of polished thin-sections were performed using a stereomicroscope Zeiss Stemi SV11 Apo coupled to a Sony Cyber-Shot DSC-S75 digital camera and also using a Leica DM LSP polarizing microscope, with transmitted and reflected light, coupled to a Leica camera with LAS EZ software 2.0.0. SEM/EDS analyses were carried out at the Materials Centre of the University of Porto (CEMUP), using a FEI Quanta 400 FEG-ESEM/EDAX Genesis X4M instrument. SEM was operated at 15 kV in high-vacuum mode, manual aperture, 4.5 m beam spot size. Raman analyses were carried out using a Raman spectrometer Horiba Jobin-Yvon LabRam microscope XploRATM equipped with an excitation wavelength of 532 nm from an Ar laser at a power of 25 mW and with diffraction gratings with 1800 lines mm-1. A 10x objective lens of an Olympus optical microscope was used to focus the laser beam on the sample and also to collect the scattered radiation. A charged coupled device (CCD) camera was used to collect the Raman spectra. Silicon (characteristic peak at 520.5 cm-1) was used as a standard for the calibration of the equipment.

Complementary studies were carried out for the flotation concentrates by X-ray powder diffraction (XRD) using a PANALYTICAL XPERT -1 for the identification of the main minerals. The Rietveld Refinement method was applied to quantify the main minerals present in the concentrate.

Table 2. Results of the froth flotation of the Lntt sample: Test A using Oleic Acid and Test B using Aero 704 as collectors (*calculated values based on mass balance). RC-Rougher Concentrate; RT-Rougher Tailings; CC-Cleaner Concentrate; CT-Cleaner Tailings; SC-Scavenger Concentrate; ST-Scavenger Tailings.

Concerning the collector comparison, it is possible to conclude that the Oleic Acid allowed for a higher concentrate grade, although at lower mineral recovery, when compared with Aero 704. It is also noted that 5.2 % Li2O is the highest grade ever obtained, result that would not be expected having in mind that the Lntt spodumene is coarse-grained, because at flotation sizes (k80=0.150 mm) there would be a significant amount of well-liberated spodumene particles, which would have allowed to obtain concentrates with grades close to the Lntt spodumene Li2O content (7.0 % Li2O [36]). It can be said that as the selectivity of the process is claimed (cleaning stage), it is possible to observe a better behavior of the grade-recovery curve, which means that some spodumene is already liberated, but it is not enough to produce concentrate grades above 5 % Li2O under higher metal recovery. Moreover, it is expected that the grade-recovery curve shows a prompt increase of the grade for high-recoveries, which is not the case, suggesting that spodumene is floating together with gangue minerals.

Table 3. Results of the froth flotation tests of the Gonalo sample (*calculated values based on mass balance). RC-Rougher Concentrate; RT-Rougher Tailings; CC-Cleaner Concentrate; CT-Cleaner Tailings; SC-Scavenger Concentrate; ST-Scavenger Tailings.

Similarly to what occurred with spodumene, it was not possible to obtain concentrates with Li2O grades close to the Gonalo lepidolite Li2O content (5.58 % Li2O [31]), even after the cleaning stage, having been 4.50 % Li2O the maximum value achieved. The shape of the grade-recovery curve indicates that the flotation of lepidolite was more efficient than in the case of spodumene, due to the faster increase of the grade in the beginning of the flotation. However, after reaching a certain value, the concentrate grade increases only slightly, when recovery decreases. This means that during the lepidolite flotation other minerals are also floating, which could be due to the lack of lepidolite liberation, even when a significant reduction in the particle size occurred.

In order to have a better understanding of the results obtained, a mineralogical study, at a detailed micrometer scale, was carried out to look for any specific textural features that could justify the processing results obtained for spodumene and lepidolite concentrates. In both cases, there were evidences of other minerals that are also floating along with the Li minerals, even after the cleaning step and working below 0.150 mm top grain size.

The mineralogy of the Lntt pegmatite was investigated by petrographic microscopy, SEM/EDS and Raman spectroscopy and it was mainly focused on the association spodumene + quartz. It was found that spodumene is intergrown with quartz. Quartz intergrowths tend to be coarser (up to 250 m long) and graphic-shaped towards the core of the large spodumene crystals, whilst near the borders, in the contact with albite and quartz grains, quartz intergrowths tend to be reminiscent of myrmekite or even fibrous (Figure 8). Similar aspects were described by [37] for Neoproterozoic spodumene pegmatites from southern Natal, South Africa. In the Iberian Peninsula, some petalite-rich pegmatites exhibit a similar texture [e.g. 38] named as SQUI [39] characterized by symplectic or fibrous intergrowths of spodumene + quartz due to the breakdown of petalite. However, it must be highlighted that petalite does not occur in the Lntt pegmatite.

Two Raman spectra were obtained: one was performed on the core of a spodumene crystal; the other was obtained on a fibrous intergrowth at the margins of this crystal. The spectrum of the fibrous material shows the overlap of the spodumene spectrum with quartz (peak at 466 cm-1), corresponding to an intergrowth of spodumene + quartz (Figure 9).

SEM analyses were also carried out. As expected, the backscattered images (BSE) show spodumene with fine quartz intergrowths, albite replacing spodumene and K-feldspar in thin veinlets (Figures 10 and 11).

Applying the Rietveld Refinement, it was possible to quantify the main minerals present in the concentrate: 59.7 % spodumene, 21.9 % albite and 18.4 % quartz. However, the refinement method did not reach a good agreement of statistical criteria due to the overlapping albite and spodumene reflections and also to the inclusions of quartz in the spodumene that produce a broadening of the peak base for the most intense reflections. This broadening of the peak base is an indicator of the presence of locked particles, even at those fine sizes.

Raman analyses performed on the Gonalo lepidolite samples (Figure 14), both from the aplitic (spectrum Lepidolite-A) and the pegmatitic facies (spectrum Lepidolite-P), show distinct Raman features: the spectrum of the pegmatitic material (coarse lepidolite) gives a typical lepidolite spectrum with well-visible peaks at 265 and 714 cm-1; in the case of the aplitic facies, the spectrum usually shows similar features to an association of lepidolite and albite (albite peaks at 297, 485 and 514 cm-1).

Applying the Rietveld Refinement, it was possible to quantify the main minerals present in the concentrate: 19.1 % albite, 23.9 % quartz and 57.1 % lepidolite. Once again, the refinement method did not reach a good agreement of statistical criteria due to the overlapping of albite and lepidolite as well as inclusions of quartz or albite in lepidolite that produce a broadening of the peak base for the most intense reflections. This broadening of the peak base is an indicator of the presence of locked particles, even at those fine sizes.

Despite the geological and mineralogical differences between Lntt spodumene and Gonalo lepidolite ores, the mineral processing of both samples was faced with the same bottleneck: very fine mineral inclusions inside the lithium minerals, which led to lithium final concentrates with grades lower than those expected, even when working at particle sizes < 150 m. During the processing of both samples, it was not possible to achieve a Li2O grade close to the Li2O content of the lithium minerals in study, even for low metal recoveries: for lepidolite, 4.50 % Li2O was the maximum grade obtained, and spodumene flotation exhibited a maximum grade of 5.20 % Li2O. It is important to notice that these grades are acceptable for the lithium metallurgy, meaning that they are not a matter of concern for the mining companies; however, it should be underlined that, for both cases, the impossibility of attaining grades close to the lithium mineral stoichiometry, is due to the ore very specific mineralogical features, rather than to any flotation inefficiencies, clearly demonstrating that these techniques are efficient tools to evaluate these types of micro-textures.

Mineralogical studies, using optical microscopy and SEM observations, XRD and Raman analyses, showed that, in the case of Lntt, spodumene occurs with fine quartz intergrowths and is crosscut by fine albite and K-feldspar to some extent, whilst microinclusions of quartz and albite were found in the Gonalo lepidolite.

If the textural aspects of the lithium-rich mineral assemblage resultant from the petrogenetic conditions observed in the two studied cases are widespread through the pegmatitic orebodies, one should be aware of possible high difficulties to reach high-lithium grades in the flotation concentrates, unless very fine grinding, far below 0.075 mm, is reached. In this case, a decrease in the flotation efficiency and entrainment of very fine particles is expected, which would rule out this degree of fineness of grind. More selective comminution methods, as innovative electro-fragmentation techniques could be a potential solution for this problem, as they can promote preferentially fragmentation along grain boundaries enhancing mineral liberation. In addition, hydro and bioleaching processes can potentially evolve as alternatives for upgrading concentrates of lower Li2O content.

All the authors acknowledge the European Unions Horizon 2020 research and innovation programme for Project FAME (Flexible and Mobile Economic Processing Technologies - grant agreement No. 641650) and also FELMICA and Keliber Oy for providing the investigated samples. Authors V. Ramos, A. Guedes and F. Noronha also acknowledge the funding by COMPETE 2020 through the ICT project (UID/GEO/04683/2013) with POCI-01-0145 reference - FEDER-007690 and also the CEMUP for performing SEM/EDS analyses. Author R. Sousa also acknowledges the Fundao para a Cincia e Tecnologia for financing the scholarship programme with the reference SFRH/BD/114764/2016. The Anonymous Reviewers are acknowledged for their constructive remarks that helped to improve the manuscript.

[11] S. Reichel, T. Aubel, A. Patzig, E. Janneck and M. Martin, Lithium recovery from lithium-containing micas using sulfur oxidizing microorganisms, Miner. Eng., vol. 106, pp. 18-21, 2017.View Article

[12] U.S. Geological Survey. (2018, June 20). Mineral Commodity Summaries. [Online]. Available: https://www.statista.com/statistics/268789/countries-with-the-largest-production-output-of-lithium/ View Article

[18] M. M. Amarante, A. Botelho de Sousa and M. Machado Leite, Processing a spodumene ore to obtain lithium concentrates for addition to glass and ceramic bodies, Minerals Engineering, vol. 12, pp. 433-436, 1999.View Article

[22] M. Menndez, A. Vidal, J. Torao and M. Gent, Optimisation of spodumene flotation, The European Journal of Mineral Processing and Environmental Protection, vol. 4, pp. 130-135, 2004.View Article

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[24] R. Alviola, I. Manttari, H. Makitie, M. Vaasjoki, Svecofennian rare-element granitic pegmatites of the Ostrobothnia region, Western Finland: Their metamorphic environment and time of intrusion, Geological Survey of Finland, pp. 9-29, 2001. View Article

[26] S. E. Kesler, P. W. Gruber, P. A. Medina, G. A. Keoleian, M. P. Eversion and T. J. Wallington, Global lithium resources: Relative importance of pegmatite, brine and other deposits, Ore Geology Reviews, vol. 48, pp. 55-69, 2012. View Article

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[29] A. M. R. Neiva and J. M. F. Ramos, Geochemistry of granitic aplite-pegmatite sills and petrogenetic links with granites, Guarda-Belmonte area, central Portugal, European Journal of Mineralogy, vol. 22, pp. 837-854, 2010.View Article

[30] J. M. F. Ramos, Locality n5: Seixo Amarelo-Gonalo rare element aplite-pegmatite field. In Granitic pegmatites: The state of the art - field trip guidebook. Memrias N.9, A. Lima, E. Roda Robles Eds. Departamento de Geologia da Faculdade de Cincias Universidade do Porto: Porto, 2007, pp. 72-86.

[34] M. M. Amarante, A. M. B. Sousa, A. Oliveira, J. M. F. Ramos, J. C. Grade and M. Leite, Processamento de Minrios de Ltio Contribuio para a Valorizao Tecnolgica de Espodumenas e Petalites, Relatrio de projecto FCT, seco de Processamento de Matrias Primas, IGM, pp. 27, 2004.View Article

[35] C. Gibson, M. Aghamirian and T. Grammatikopoulos, A review: The beneficiation of lithium minerals from hard rock deposits, in Proceedings of the SME Annual Meeting, Denver, CO, 2017.View Article

[37] R. J. Thomas, D. Biihmann, W. D. Bullen, A. J. Scogings and D. De Bruin, Unusual spodumente pegmatites from the Late Kibaran of southern Natal, South Africa, Ore Geology Reviews, vol. 9, pp. 161-182, 1994.View Article

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