Generic name: zinc oxide topical (ZINK OX ide)Brand name: ARC, Balmex, Boudreaux Butt Paste, Caldesene, Calmol-4 Suppository, Critic-Aid Skin Paste, Delazinc, Desitin, Dr. Smith's Rash + Skin, Flanders Buttocks Ointment, Geri-Protect, Pinxav, Rash Relief, Secura Protective Cream, Seniortopix Healix, Unna-Flex Elastic Unna Boot 4 inch, Z-Bum, Znlin, ...show all 59 brand namesRVPaque, Unna-Flex(obsolete), PNS Unna Boot, Lassars Zinc, Sportz Block Light, Sportz Block Medium, Sportz Block Dark, Nupercainal Suppository, Desitin Creamy Diaper Rash Ointment, Vaginex Powder, Yeast-X Powder, Mexsana, Critic Aid, Tronolane Suppositories, Calmoseptine Ointment (obsolete), Zincofax, Desitin Creamy, Secura Antifungal Extra Thick(obsolete), Triple Paste, Johnsons Diaper Rash, Penaten Soothing, Aveeno Diaper Rash, Diaper Rash Ointment, Diaper Relief, PeriGuard, Unna Boot Primer (obsolete), Medi-Paste, Dermagran BC, Dr. Smith's Diaper, Soothe & Cool Skin Paste, Unna-Flex Elastic Unna Boot 3 inch, Desitin Maximum Strength Original, Desitin Rapid Relief Creamy, Dr. Smith's Diaper Rash, Dr. Smith's Adult Barrier, Secura Extra Protective Cream, Balmex Adult Care, Balmex Diaper Rash, Boudreaux's Maximum Strength Butt Paste, Desitin Maximum Strength, Unna Boot PrimerDosage forms: rectal suppository (10%); topical cream (-; 10%; 11.3%; 13%; 22%; 30.6%); topical dressing (-); topical lotion (-); topical ointment (-; 10%; 16%; 20%; 30%; 40%); topical paste (20%; 40%); topical powder (15%); topical spray (10%; 25%); topical stick (11.3%)Drug class: Miscellaneous topical agents
To treat diaper rash, use zinc oxide topical each time the diaper is changed. Also apply the medicine at bedtime or whenever there will be a long period of time between diaper changes. Change wet diapers as soon as possible. Keep the diaper area clean and dry.
When using the zinc oxide topical powder, pour the powder slowly to avoid a large puff into the air. Do not allow a baby to handle a powder bottle during use. Always close the lid after using the powder.
Remove the wrapper before inserting the suppository. Avoid handling the suppository too long or it will melt. Lie on your back with your knees up toward your chest. Gently insert the suppository into your rectum about 1 inch, pointed tip first.
Zinc oxide 10%, 11.3%, 13%, 16%, 20%, 22%, 30.6% and 40% cream, 16% and 20% ointment, 12.8% and 40% paste, 15% powder, and 25% spray: Apply liberally as often as needed with each diaper change, especially at bedtime or any time exposure to soiled diapers may be prolongedComments:-For external use only-Change wet/soiled diapers promptly, cleanse diaper area and allow to dry.
Zinc oxide 10%, 11.3%, 13%, 16%, 20%, 22%, 30.6% and 40% cream, 16% and 20% ointment, 12.8% and 40% paste, 15% powder, and 25% spray: Apply liberally as often as needed with each diaper change, especially at bedtime or any time exposure to soiled diapers may be prolongedComments:-For external use only-Change wet/soiled diapers promptly, cleanse diaper area and allow to dry.
Medicine used on the skin is not likely to be affected by other drugs you use. But many drugs can interact with each other. Tell each of your healthcare providers about all medicines you use, including prescription and over-the-counter medicines, vitamins, and herbal products.
Drugs.com provides accurate and independent information on more than 24,000 prescription drugs, over-the-counter medicines and natural products. This material is provided for educational purposes only and is not intended for medical advice, diagnosis or treatment. Data sources include IBM Watson Micromedex (updated 1 July 2021), Cerner Multum (updated 1 July 2021), ASHP (updated 30 June 2021) and others.
Circular vibrating screener is a new-type and high efficient machine which moves circularly and has multi-layers. The machine uses the eccentric shaft vibration-exciter and the eccentric blocks to adjust the amplitude.
Circular vibrating screener is a new-type and high efficient machine which moves circularly and has multi-layers. The machine uses the eccentric shaft vibration-exciter and the eccentric blocks to adjust the amplitude.It possesses the features of many specifications, reliability, strong exciting force, high efficiency, little noise, durability, convenient maintenance and safety.Vibrating screen machine is applied to sieveing and filtering powder, partical and liquid in different fields.
Its vertical motor, which is installed eccentric hammers on the top and bottom, is regarded as a vibratory source. The eccentric hammers change rotation into horizontal, vertical and inclined movement, and then pass the movement to the sieving surface. Adjusting the phase angle on the top and bottom can change trajectories of the materials on the sieve.
3) Food industry: sugar, salt, alkali, gourmet powder, starch, milk powder, yeast powder, pollen, food additive, bean milk, juice, etc. 4) Papermaking industry: coated slurry, exhaust liquid, paper making liquid and waste water reclamation, etc.
Xinxiang Senyou Mechanical And Electrical Co. Ltd., is a technological ceramic-machinery enterprise created by a team of long time ceramics engineers.Senyou makes every effort to produce multi functional machines with modern design, and high practicability &reliability,there is great innovation in our products, therefore Senyou wins a wide favors from customers. Senyou offers the widest range of sieving and filtration equipment for ceramic,mainly produces slurry vibrating sieve,drum vibrating sieve,flat vibrating sieve, high-frequency glaze vibrating sieve,dry-powder vibrating sieve,etc.
mechanics.Their average working experience is more than 10 years. We are focus on quality, innovation and devote ourselves to technology development all the time. With the professional technical teams and richly manufacturing experience, we can supply excellent vibrating machines for global customers.
3.Emergency Services: if you are located within 1000 kilometers in domestic,Senyou under take to arrive at the spot in 48 hours after receiving reports;if you are not,72 hours services would be served.
4.Spare Parts Supply: In order to offer the timely services,Senyou has set up a number of warehouses and services offices.We will keep enlarging offices and keep spare parts available in stock for soonest supply to customers.
Senyou offersthe widest range of sieving and iron removing equipment for Food,Mining,Ceramics &Chemical Industry, etc. Its innovation ability, manufacturing capability and products sales volumes have consistently ranked in the forefront of the domestic ,and products are exported to Europe, AsiaandAmerica, more than 10 countries and regions.
Gold recovery from copper-zinc ores is usually higher than that obtained from either a lead-zinc or copper lead-zinc ore. This is attributed to two main factors: when selecting a reagent scheme for treatment of Cu-Zn ores, there are more choices than for the other ore types, which can lead to the selection of a reagent scheme more favourable for gold flotation. In addition, a non-cyanide depressant system can be used for the treatment of these ores, which in turn results in improved gold recovery. This option is not available during treatment of lead-zinc ores. Table 17.9 shows the effect of different depressant combinations on gold recovery from a copper-zinc ore.
There are several operations that treat oxide lead zinc ores, including several operations in Sicily, Morocco and Mexico. The beneficiation flowsheets, in general, are similar to those found in most operating plants. The generalized flowsheet is presented in Figure 20.5.
Collector sterylamine acetate works well on smithsonite, but not as well on calamine. When smithsonite is present in the ore, better results are achieved using a tallow amine emulsion with elevated additions of fuel oil emulsion.
Metallurgical results obtained in an operating plant in Morocco are presented in Table 20.10. An appreciable amount of zinc reported to the slime fraction. Attempts were made by some researchers to float oxide zinc from the slimes, but with little success.
The international standard method for the determination of precious metals has been mainly discussed in ISO/TC183 (copper, lead, and zinc ores and concentrates) and ISO/TC174 (Jewelry). Table 2 shows the ISO international standard methods published or discussed. Accurate sampling methods, for example, fire assay, titrimetric method, and/or gravimetric method are regulated in almost all international standards for precise and true determination, because of international trading of expensive precious metals. Another method for the determination of precious metals content is by subtraction of the total content of impurities in the sample from 100%, which is also regulated. In these cases, atomic absorption spectrometry (AAS) and/or inductively coupled plasma-atomic emission spectrometry (ICP-AES) is utilized for the final detection.
Minerals dominated by cadmium are rare; the sulfide CdS (greenockite), especially, is very rarely found. However, cadmium is widespread in zinc ores in low concentrations (0.20.4%) and is separated during processing of these ores and production of zinc.
It is now established that cadmium, besides zinc, is accumulated in some native cysteine-rich proteins (e.g., metallothioneins) and the binding mode and sites in the protein are studied and largely understood.57 Also, the detection and study of native Cd-enzymes and Cd-substituted Zn-enzymes is just beginning at the time of writing (for a short survey see ref. 58).
In contrast to cadmium, mercury occurs in various mineralspartly highly interesting in view of the mercury species presentand in enriched deposits. The most remarkable and important of these is the mine of Almadn, Spain, already known and exploited for cinnabar by the Romans, i.e., for more than two thousand years. Almadn still contributes about one-third of the world production of mercury. The geology and geochemistry of this region have been reviewed.59 Recently, exploration in the Almadn district detected a new deposit, Nuevo Entredichoeven more remarkable in that the mercury content of this cinnabar/native mercury deposit locally rises up to 45% and that the deposit is actually monometallic, i.e., the HgS/Hg mixture contains other metals only at the trace level of some umpteen ppm, with lead reaching a maximum of more than 1,000ppm in some parts. On the basis of the results of isotope analyses for sulfur and lead, conclusions on the geological and geochemical history of the deposit have been drawn.60
The common occurrence of a mercury(II) compound and metallic mercury in this and other deposits could lead to the secondary formation of minerals with mercury in lower oxidation states: for instance, in the intermediate oxidation state +11/3 of the highly remarkable triangulo-Hg34+ entity in the minerals terlinguaite (Hg3)HgO2Cl26163 and kuznetsovite (Hg3)AsO4Cl;6466 or in the oxidation state +1 of the Hg22+ dumbbells in the long-known but only recently structurally studied mineral eglestonite (Hg2)3Cl3O2H,67,68 in the newly found shakhovite (Hg2)2Sb(OH)3O3,69,70 and in the deceptively simple-looking, but structurally complicated, poyarkovite Hg3OCl (six independent Hg22+ groups!).71
The dye is obtained by aerating sodium gallate (NaGa2O3) or potassium gallate (KGa2O3). The sodium gallate is obtained from the tailing of aluminium and zinc ores. The tailings of aluminium and zinc ores, left after the extraction of aluminium and zinc, mixed with the solution of caustic soda gives a solution of sodium gallate. The sodium gallate solution is then accreted at 0C for about 5h yields a yellow precipitate of galloflavin. The precipitate of galloflavin is then filtered and redissolved in water, and then dried under reduced pressure. Thus, pale yellow prisms of galloflavin are obtained.
The most frequently used reagent for the determination of gallium is rhodamine B. Butylrhodamine is also used for the determination of gallium in unroasted lead dust, bauxites, copperzinc ores, and quartztopaz greisens. In the procedures based upon rhodamine B, the red-colored compound formed with the chlorogallate anion is extracted into organic solution prior to the measurement of the optical density. This chapter discusses the procedure of separation with di-isopropyl ether, followed by the extraction of rhodamine chlorogallate into chlorobenzene-carbon tetrachloride in the presence of acetone. The chapter describes the determination of gallium by atomic absorption spectroscopy (AAS). The level at which gallium occurs in most silicate rocks and minerals is too low for direct determination by this technique using a typical rock solution directly aspirated into a suitable flame or when using a solvent extraction technique to effect the concentration increase. The inherent higher sensitivity obtainable using flameless atomic absorption can be combined with a solvent extraction concentration step, which serves also to reduce matrix interferences.
Because there are no real germanium minerals the overall production process is always divided into two steps: production of germanium concentrate and the production of germanium. As described in the previous section the two main sources are zinc ores and coal. From the first one the germanium is concentrated either through a pyrometallurgical or hydrometallurgical process. The most common process is the pyrometallurgical one. The germanium is volatized as GeO or GeS. From coal, germanium volatizes as GeO and is concentrated in the fly ashes. In both processes concentrations of 1 to 6% Ge are reached. Another important source today is the recycling of Ge coming from the optical fiber industry like scrubber solutions and glass scraps. Except for glass scrap, direct chlorination of these products is possible but with low yields. The obvious process is pyrometallurgical.
Subsequent filtration and appropriate drying yields various grades of GeO2. Electronic grade GeO2 is reduced in a hydrogen atmosphere. Care has to be taken to avoid generation of volatile GeO. Therefore, the temperature must be kept below 700C during the reduction process.
Nanisivik is a village located in the extreme north of Baffin Island at the 73 parallel where Nanisivik Mines exploits a zinc mine (Figure21.1). An airport is connected to Ottawa twice a week and a harbour facility exists to ship the extracted zinc ore.
To study the feasibility of using grouts containing calcium nitrite as an antifreeze admixture, it was possible to take advantage of all of the facilities of the mining company (food and dwelling, drills, transportation, etc.) and establish a temporary small laboratory inside a garage.
Two series of experiments were done: the first one in a cap of rock close to the plant as seen in Figure21.2 and a second one in a gallery of the mine where the rock and the air were all year round at12C (Figure21.3).
The grouts were prepared in a garage using water at 10C and transported to the site immediately to be poured in the anchor holes. They contained some aluminium powder in order to create a small expansion of the volume of the grout to improve the bonding of the grout with the anchor and the rock. Only the first 300mm of the anchors were grouted and thermocouples installed at the bottom of the anchor to monitor the temperature of the grout (Figures21.4 and 21.5). The composition of the grout is shown in Table21.1.
On the cap of rock, the anchors were pull out after 14days. In the frozen gallery of the mine, the anchored bars were supposed to be pulled out 1year later. A small rectangular base was built around each anchor to support the base of the hollow jack used to pull out the anchors (Figure21.5).
The results obtained on the cap of rock were compared to those obtained in an unfrozen rock in Sherbrooke; they were excellent (Benmokrane etal., 1987). However, in the case of the anchors grouted in the frozen gallery, after a year at12C it was impossible to pull them out because by error the grouted length was too long; the load that had to be developed to extract them was well over the capacity of the jack. It was necessary to cut the anchors with acetylene torches and seal the anchoring hole with a grout to avoid any accident in the gallery.
Very often leadzinc, copperzinc, copperleadzinc and coppernickel ores contain significant quantities of gold (i.e. between 1 and 9g/t). The gold in these ore types is usually found as elemental gold. A large portion of the gold in these ores is finely disseminated in pyrite, which is considered nonrecoverable. Because of the importance of producing commercial-grade copper, lead and zinc concentrates, little or no consideration is given to improvement in gold recovery, although the possibility exists to optimize gold recovery in many cases. Normally, gold recovery from base metal ores ranges from 30 to 75%.
In the case of a copperzinc and copperleadzinc ore, gold collects in the copper concentrate. During the treatment of leadzinc ores, the gold tends to report to the lead concentrate. Information regarding gold recovery from base metal ores is sparse.
The most recent studies conducted on various base metal ores revealed some important features of flotation behaviour of gold from these ores. It has been demonstrated that gold recovery to the base metal concentrate can be substantially improved with the proper selection of reagent schemes. Some of these studies are discussed below.
Some of these ores contain significant quantities of gold, ranging from 0.9 to 6.0g t1 (e.g. Grum, Yukon, Canada; Greens Creek, Alaska and Milpo, Peru). The gold recovery from these ores ranges from 35 to 75%. Laboratory studies have shown that the use of high dosages of zinc sulfate, which is a common zinc depressant used in lead flotation, reduces gold floatability significantly. The effect of ZnSO47H2O addition on gold recovery in the lead concentrate is illustrated in Figure 6.
In order to improve gold recovery in the lead concentrate, an alternative depressant to ZnSO47H2O can be used. Depressant combinations such as Na2S+NaCN, or Na2SO3+NaCN, may be used. The type of collector also plays an important role in gold flotation of leadzinc ores. A phosphine-based collector, in combination with xanthate, gave better gold recovery than dithiophosphates.
Gold recovery from copperzinc ores is usually higher than that obtained from either a leadzinc or copperleadzinc ore. This is attributed to two main factors. When selecting a reagent scheme for treatment of copperzinc ores, there are more choices than for the other ore types, which can lead to the selection of a reagent scheme which is more favourable for gold flotation. In addition, a noncyanide depressant system can be used for the treatment of these ores, which in turn results in improved gold recovery. This option is not available during treatment of leadzinc ores. Table 9 shows the effect of different depressant combinations on gold recovery from a copperzinc ore.
Because of the complex nature of these ores, and the requirement for a relatively complex reagent scheme for treatment of this ore, the gold recovery is generally lower than that achieved from a leadzinc or copperzinc ore. One of the major problems associated with the flotation of gold from these ores is related to gold mineralogy. A large portion of the gold is usually contained in pyrite, at sub-micron size. If coarser elemental gold and electrum are present, the gold surfaces are often coated with iron or lead, which can result in a substantial reduction in floatability.
The type of collector and flow sheet configuration play an important role in gold recovery from these ores. With a flow sheet that uses bulk copperlead flotation followed by copperlead separation, the gold recovery is higher than that achieved with a sequential copperlead flotation flow sheet. In laboratory tests, an aerophine collector type, in combination with xanthate, had a positive effect on gold recovery as compared to either dithiophosphate or thionocarbamate collectors. Table 10 compares the metallurgical results obtained with an aerophine collector to those obtained with a dithiophosphate collector.
Because of the complex nature of gold-containing copperleadzinc ores, the reagent schemes used are also complex. Reagent modifiers such as ZnSO4, NaCN and lime have to be used, all of which have a negative effect on gold flotation.
Beneficiation of complex base metal sulfide ores is based on selective production of individual clean concentrates of copper, zinc, and lead. Sphalerite flotation through copper activation becomes complicated when other minerals such as pyrite can get inadvertently activated.
Adsorption density of cells of P. polymyxa was found to significantly higher on pyrite than on sphalerite irrespective of pH. Adsorption on sphalerite was the highest in acidic pH regions only (26), beyond which cell adsorption decreased steeply.
Flocculationdispersion behavior of pyrite and sphalerite was seen to be influenced by interaction with bacterial cells and their metabolic products as a function of pH, cell density, and bioreagent concentrations. For example, more than 90% of pyrite particles were observed to be flocculated and settled at pH 89 in the presence of bacterial cells, while sphalerite was preferentially dispersed. Similarly, interaction with EBP isolated from metabolites promoted selective flocculation of pyrite and dispersion of sphalerite. On the other hand, interaction with ECP was not very effective in separation of pyrite from sphalerite because the selectivity ratio was very poor. Pyritesphalerite separation can be effectively achieved through selective bioflocculation of pyrite and dispersion of sphalerite using either bacterial cells or bioproteins.
Pyrite can also be selectively depressed through bioflotation after bacterial conditioning. Flotation tests using 1:1 mixtures of pyrite and sphalerite indicated that prior bacterial interaction followed by xanthate conditioning and copper activation resulted in preferential flotation of only sphalerite, while pyrite was depressed.
Pyrite could also be similarly removed from galena because differential adsorption and surface chemical behavior of P. polymyxa cells as well as proteins and polysaccharides were also observed on pyrite and galena as well. Selective bioflocculation in the presence of either bacterial cells or extracellular proteins could selectively flocculate pyrite from pyritegalena mixtures. Galena was also found to be selectively flocculated after interaction with exopolysaccharides. Similarly selective flotation of galena along with efficient pyrite depression could be attained after interaction with extracellular proteins.
A. ferrooxidans have been used to demonstrate selective pyrite depression from a low-grade leadzinc ore. Both sphalerite recovery and zinc grade in the floated sphalerite concentrate were enhanced by bacterial cells in the absence of conventionally used cyanides .
New technology is developed for Waelz treatment of electric arc furnace dust with the addition of calcium oxide to a charge. In this case, lead and halides are transferred into distillates. Calcium ferrite and zinc oxide remain in clinker. Clinker is sent for leaching zinc followed by zinc electrolysis from solution. The insoluble residue of calcium ferrite is used in ferrous metallurgy. The efficiency of this technology is determined by the process of charge preparation for loading into a Waelz kiln. In order to provide complete reaction of zinc ferrite with calcium oxide, it is necessary to provide effective component mixing; in order to provide selectivity of halide and lead liberation, reducing distillate volume, a powder mixture is pelletized. Exploratory research is conducted for preparing pellets of a mixture of electric arc furnace dust with lime, and the effect of some binder reagents on pellet strength is demonstrated. The following optimum parameters are determined for charge pelletizing from electric arc furnace dust and calcium-containing flux under conditions of a plate-like granulator: pelletizing duration 15 min; granule moisture content 1920%. With the use of an intense type mixer-pelletizer, the optimum moisture content is 1314%, which is connected with the improved conditions for pellet compaction. Comparison of various inorganic and organic additives for mixture granulation shows that the best are additives containing sodium hydrate sulfate, although their optimum consumption is unacceptable for the technology of material pyrometallurgical treatment. The presence in the production mixture of calcium-containing flux makes it possible to use it also as a binding additive for pelletizing calcium hydroxide in the form of an aqueous suspension. Feeding a pelletized mixture of electric arc furnace dust with lime into a Waelz kiln makes it possible to provide effective reaction of charge components in the kiln and to reduce to reduce escape of dust.
P. J. W. K. de Buzin, N. C. Heck, and A. C. F. Vilela, EAF dust: An overview on the infl uences of physical, chemical and mineral features in its recycling and waste incorporation routes, J. MRT., 10/002 (2016).
P. J. W. K. de Buzin, N. C. Heck. L. A. H. Schneider, et al., Study of carbothermic reduction of self-reducing briquettes of EAF dust and iron scale for use electric steelmaking, Proc. 66th Congr. ABM (2011), pp. 12681279.
S. Wegscheider, S. Steinlechner, C. Pichler, et al., Innovative treatment of electric arc furnace dust, Selected Papers from the 3rd Edition of Int. Conf. on Wastes: Solutions, Treatments and Opportunities WASTES 2015, Viana Do Castelo, Portugal, Sept. 1416, 2015, CRC Press (2015), p. 378.
Yakornov, S.A., Panshin, A.M., Kozlov, P.A. et al. Development of Charge Pelletizing Technology Based on Electric Arc Furnace Dust for Pyrometallurgical Processing in Rotary Kilns. Metallurgist 61, 529534 (2017). https://doi.org/10.1007/s11015-017-0528-3
When considering the use of an industrial mixer, be it for pre-conditioning prior to a disc pelletizer, or as a stand-alone agglomeration unit, it is often common to run into the question of which mixer will serve the process and material best: a pin mixer, or a paddle mixer. While both pieces of equipment are considered industrial mixers, they each have distinct benefits and capabilities. Typically, the material itself, along with processing considerations, will help in determining which piece of equipment will best fit the needs of the process and material. The following information outlines the basics on each mixers capabilities.
FEECOs paddle mixer is a U-shaped, horizontal trough. Inside the trough, a series of pitched paddles are mounted on dual counter-rotating shafts that run the length of the device. The paddles move material from the bottom of the trough, up the middle, and back down the sides, creating a kneading and folding effect that intimately mixes the material. Pugmill Mixer (Pug Mill, Paddle Mixer) Interior
The paddle mixer is also used for conditioning or agglomerating material. In these instances, a liquid spray system is added to dispense a binder that assists with the conditioning or agglomerating process.
The pin mixer is comprised of a stationary cylindrical shell that houses a high velocity central rotor shaft. The rotor shaft extends the full length of the mixer, with numerous rods (or pins) that extend outward. A constant speed motor spins the rotor shaft at several hundred RPMs in order to impart agitation forces on the material. The motion and high rotational speeds produced by the pin mixer minimize air and reduce water volume between particles in the material. This results in densification many times that of a disc pelletizer. A fluid binder material is added in order to aid in the agglomeration process. Pin Mixer Interior
Pin mixers work well as a stand-alone agglomeration unit, or as a pre-conditioner in a two-stage agglomeration process involving a disc pelletizer. Pin mixers are also ideal components in an automated system, offering precise quality control and accurate production rates.
Paddle mixers and pin mixers both provide a wide array of benefits and processing capabilities. When choosing which industrial mixer to use, the material may help in determining what equipment should be selected. Processing system requirements and facility considerations are also used to determine the best equipment solution. However, the best way to choose between a paddle mixer and a pin mixer is to evaluate the raw material and decide what type of outcome is preferred; the equipments capabilities will lead to choosing one device over the other. The most common considerations in making a decision between the two types of mixers are listed below.
A paddle mixer tends to handle sticky and/or abrasive materials a little better than a pin mixer, because of its slower speed. Pin mixers would likely get bogged down when trying to process a sticky material, and would not stand up as well to a severely abrasive material, due to the high rotational speed.
A paddle mixer is also more forgiving than a pin mixer, an ideal characteristic when working with tougher materials, or where tramp could possibly enter the mixer. While a stray rock or tramp bolt may cause a few pins to break off in a pin mixer, the paddle mixer would likely not see any damage.
The same is true when working with large particle sizes. Large particles could lodge between the pin tips and the interior wall of the pin mixer. In a paddle mixer, however, the clearance between the trough and paddles is greater, decreasing opportunity for this. There is also typically enough torque in a paddle mixer to dislodge the particle as well, should it get stuck.
When looking to densify a material, the high-speed spinning action that occurs in a pin mixer can offer much better results than a paddle mixer. Pin mixers also excel in working with ultra-fine materials, such as pigments and dyes. The pin mixers ability to effectively micro-pelletize a fine powder is tough to beat.
As can be seen, the choice between a pin mixer and a paddle mixer is often dictated by the material itself. Both pin mixers and paddle mixers are effective industrial mixers, with each offering their own advantages and disadvantages. For more information on paddle mixers and pin mixers, contact us today!
Industrial pigments play an important role in the performance and durability of many products. In addition to serving as a coloring agent, pigments can also offer protection against corrosion and even UV rays; pigments are all around us, from building materials and concrete, to textiles, papers, printing inks, artists paints, and more.
An increasing demand for specialty products, combined with prolific use in plastics, paints, coatings, and other applications has experts estimating that the pigment market will see a CAGR of 4.5% between 2016 and 2024.
While there are many potential avenues used to produce pigments, many of these processes have one piece of equipment in common: the rotary kiln. Rotary kilns play an integral role in producing many of the high quality pigments industries rely on today.
Rotary kilns are a high temperature thermal processing device used throughout many of these processes to cause a physical change or chemical reaction in the material in order to impart the intended pigment properties. They are often used to carry out the diverse objectives pigment producers require, such as thermal decomposition, oxidation, calcination, reduction, and more.
Processing conditions can have a significant impact on the properties of the pigment and must be carefully controlled to achieve the desired results. This careful control is one of the advantages of the rotary kiln, which can be engineered to create the exact processingatmosphere and conditions required to influence pigment properties such as color, particle size, and even tinting strength. Typical customized design considerations include:
Titanium dioxide (TiO2) is the most commonly used material for creating white pigments. In producing TiO2 pigments, the rotary kiln is critical to carrying out one of two primary methods of production: The Sulfate Process.
The Sulfate Process is typically used for lower grade ores. In this process, the titanium ore goes through various steps in order to extract the titanium dioxide and produce it in a hydrated form that can be calcined.
The direct process relies first on reducing a zinc-containing raw material or metal. This is carried out in a rotary kiln at high temperatures with coal as the reducing agent. Once the material is reduced to zinc, the metal vapor can be oxidized to produce zinc oxide.
There are a few variations on the indirect process, which involves the melting and vaporization of zinc-containing metals, followed by oxidative combustion. In one variation on this process, the rotary kiln is used to carry out these objectives. The advantage in this setting is that the heat of combustion can be utilized elsewhere in the plant.
Calcination of Filter Cake: Barium sulfate and zinc salt are mixed to create a uniform solution. Crystallites of raw lithopone are formed and the resulting filter cake is calcined in a direct-fired rotary kiln. Upon calcination, the mixture goes through a number of additional steps including quenching, classification and separation, thickening, filtering, washing, drying, and grinding in order to produce a suitable pigment.
Iron oxides provide a diverse range of earth tone hues to the pigment industry. In the production of iron oxide pigments (IOPs), rotary kilns can be used to carry out a variety of different objectives.
The rotary kiln is used in the production of IOPs in the Laux process, and can also be used after any of the three main IOP production methods in order to carry out calcination on the pigments to produce a variation of red hues.
Testing is first carried out at batch scale to gather initial process data and define the parameters that will produce the desired product. This may include any number of factors, but generally includes gathering data on residence time, temperature profile, airflow, and more. Samples may also be produced for field testing needs.
The data gathered during batch testing can then be used in continuous, pilot-scale testing trials to develop the data necessary for process scale-up. Various test kilns are available in the FEECO Innovation Center to accommodate all pigment testing possibilities. Our thermal testing capabilities are also complemented by our agglomeration (particle size enlargement) testing services and system expertise.
The examples listed here represent just a few of the methods in which the rotary kiln provides a key processing medium to produce an ideal pigment product. The customizability of the rotary kiln to carry out various objectives makes the rotary kiln an ideal process setting for both the production and enhancement of many types of pigments. To find the ideal process solution, testing at batch and pilot scale are often a necessity.
In addition to our thermal testing capabilities offered in the Innovation Center, FEECO provides custom rotary kilns and calciners for all of your pigment processing needs. Our highly engineered systems are designed around your exact specifications and requirements to provide optimal processing. In addition to our rotary kilns, we also offer a variety of agglomeration equipment for improving the handling qualities of pigments, as well as a wide range of material handling equipment. For more information on our pigment processing capabilities, contact us today!
Prominer maintains a team of senior gold processing engineers with expertise and global experience. These gold professionals are specifically in gold processing through various beneficiation technologies, for gold ore of different characteristics, such as flotation, cyanide leaching, gravity separation, etc., to achieve the processing plant of optimal and cost-efficient process designs.
Based on abundant experiences on gold mining project, Prominer helps clients to get higher yield & recovery rate with lower running cost and pays more attention on environmental protection. Prominer supplies customized solution for different types of gold ore. General processing technologies for gold ore are summarized as below:
For alluvial gold, also called sand gold, gravel gold, placer gold or river gold, gravity separation is suitable. This type of gold contains mainly free gold blended with the sand. Under this circumstance, the technology is to wash away the mud and sieve out the big size stone first with the trommel screen, and then using centrifugal concentrator, shaking table as well as gold carpet to separate the free gold from the stone sands.
CIL is mainly for processing the oxide type gold ore if the recovery rate is not high or much gold is still left by using otation and/ or gravity circuits. Slurry, containing uncovered gold from primary circuits, is pumped directly to the thickener to adjust the slurry density. Then it is pumped to leaching plant and dissolved in aerated sodium cyanide solution. The solubilized gold is simultaneously adsorbed directly into coarse granules of activated carbon, and it is called Carbon-In-Leaching process (CIL).
Heap leaching is always the first choice to process low grade ore easy to leaching. Based on the leaching test, the gold ore will be crushed to the determined particle size and then sent to the dump area. If the content of clay and solid is high, to improve the leaching efficiency, the agglomeration shall be considered. By using the cement, lime and cyanide solution, the small particles would be stuck to big lumps. It makes the cyanide solution much easier penetrating and heap more stable. After sufficient leaching, the pregnant solution will be pumped to the carbon adsorption column for catching the free gold. The barren liquid will be pumped to the cyanide solution pond for recycle usage.
The loaded carbon is treated at high temperature to elute the adsorbed gold into the solution once again. The gold-rich eluate is fed into an electrowinning circuit where gold and other metals are plated onto cathodes of steel wool. The loaded steel wool is pretreated by calcination before mixing with uxes and melting. Finally, the melt is poured into a cascade of molds where gold is separated from the slag to gold bullion.
Prominer has been devoted to mineral processing industry for decades and specializes in mineral upgrading and deep processing. With expertise in the fields of mineral project development, mining, test study, engineering, technological processing.
specification that the DRI pellets are not oxidized nor reduced while descending through the top segment so that their mass and composition entering the bottom segment are the same as when they are top charged; and
replacement of [mass scrap steel descendinginto the bottom segment] column of Chapter 43, Top-Charged Scrap Steel, with [mass DRI pellets descendinginto the bottom segment] column as shown in Table 44.1.
In a DR process, iron ore pellets and/or lump iron ores are reduced by a reducing gas to produce DRI or hot briquetted iron (HBI). Depending on the generation of the reducing gas, two different DR processes are commercially available: gas-based and coal/oil-based. In the gas-based DR process, the reducing gas is produced by chemically reforming a mixture of natural gas and off-gas from the reducing furnace to produce a gas that is rich in hydrogen and carbon monoxide. Typical examples of the gas-based DR process include MIDREX and HYL, which are often the preferred technology in countries where natural gas is abundant. However in the coal/oil-based DR process, the reducing gas is generated from hydrocarbons (primarily coal, but sometimes oil and natural gas) in the reduction zone of the furnace, which is typically a rotary kiln. Typical examples of the coal-based process include the SL/RN and ACCAR processes. The coal-based DR process is more popular in India and China. Different types of reactors, such as shaft furnaces, fluidized beds, rotary kilns, and rotary hearth furnaces, have been used in different variations of the processe to achieve the metallization required.
Based on statistics (Anon 3, 2014), India is the world leader in DRI production producing about 17.8Mt of DRI in 2013, approximately one-forth of world DRI production. The gas-based DR processes are producing almost 80% of the world's DRI. MIDREX is the key variant of the gas-based DR processes accounting for about 63.2% of world DRI production in 2013, followed by HYL (15.4%). Therefore, the following discussion focuses mainly on the MIDREX process.
The free swelling test determines the volume increase of iron ore pellets during reduction. When pellets were first introduced, a swelling tendency led to damage to the BF stack, poor permeability to gas flow, and irregular burden descent. The test does not apply to lump ore or sinter.
An electrically heated furnace with a vertical reduction tube that contains a wire basket with room for 18 individual pellets is used. The pellets with sizes ranging from 10 to 12.5mm are placed in three levels of six pellets each. The tube is 75mm in diameter and is preheated by hot reduction gas flowing in the space between the walls. The pellets are dried at 105C, and their volume is measured. Afterward, they are placed in the wire basket and lowered into the test furnace. The pellets are first preheated with hot inert gas to the test temperature of 900C in a N2 atmosphere, after which reduction gas with composition 30%/70% (CO/N2) is introduced at a flow rate of 15L/min. The pellets are subjected to isothermal reduction at 900C for 60minutes. The reduction gas is then substituted with N2 gas and the pellets are cooled to room temperature. The post test volume of the pellets is measured, and the free swelling index is expressed as the percent volume increase.
There are two main types of pelletizer that are used to produce iron ore pellets at industrial scale, the rotary drum and the disc. Besides iron ore agglomeration, these pelletizers can also be used for other materials such as copper ore, gold ore, coal, and fertilizer .
The rotary drum pelletizer was first used for taconite pellets in the early 1940s [14, 18]. A large drum-shaped cylinder is slightly elevated at one end, approximately 34. The iron ore and binder mixture enters the high end and finished pellets exit the low end. A roller screen is usually attached to the exit to separate pellets within the desired range from undersize and oversize, the latter two streams being recirculated (oversize after being crushed). The recirculating load tends to be approximately 150250% by weight of feed. Although a rotary drum pelletizer requires a roller screen it provides a more complete control of size. For a drum pelletizer flow sheet, see Figure 1.2.6.
Disc pelletizers are also used extensively worldwide. The advantage of the disc pelletizer is that there is no recirculation. The desired blend is fed to the pelletizer, which is a large disc inclined at 4060 to the horizontal (Figure 1.2.7). The rotation of the disc causes the formation of seeds, which grow into full-sized pellets. Factors affecting the final pellet size include the disc angle, feed rate, water addition, and rotation speed. As the diameter of the pelletizer increases, the speed should be decreased, otherwise due to the high impact pellets will start breaking. Disc pelletizers are very simple to design and have excellent performance .
Available sources of iron oxide include high-grade lump ore, beneficiated iron ore fines, iron ore pellets, and agglomerates from dusts produced by the BF, basic oxygen furnace, and the EAF. Most DRI is produced in shaft furnaces, which require a uniform-sized coarse feed. Due to the high gas velocities and abrasive conditions in shaft furnaces, fine particles are not suitable as charge materials. They tend to be carried out with the gas stream, from which they must be collected and recirculated. Fluidized bed DR processes are exceptions. Shaft furnaces use pellets (produced in the same way as pellets for the BF), or lump ore. Raw material for pellets is produced by crushing and grinding low-grade iron orestypically of the taconite class and finer than 325 mesh (0.044mm)and magnetically separating the iron oxide (magnetite, Fe3O4) from the siliceous gangue. The fine particles are reconstituted into moist pellets about 1cm in diameter, and then indurated by heating to temperatures approaching 1300 C. This is sufficient to bring about complete oxidation to recrystallized hematite (Fe2O3).
There are some key differences in the pellet chemistry for DRI versus BF use. In DRI production, the primary chemical change is the removal of oxygen and the addition of some carbon; the other constituents remain with the DRI. In smelting, the formation of a slag allows substantial removal of the ore contaminants. For this reason, the iron content of DRI pellets should be as high as possible and preferably >67%. Pellet reducibility, strength, and swelling specifications are similar to those of BF pellets. Coal-based processes have the potential disadvantage of contributing coal ash oxides to the product.
The term induration describes the hardening of a powdery substance. For example, in steel production, iron ore pellets are fed into melt furnaces. To avoid dusting and loss of ore, small oxide particles are agglomerated by sintering. Although initially applied to iron ore, soon the briquette agglomeration concept spread to a variety of materials .
Percy  describes iron ore agglomeration in 1864 and notes how oxide inclusions are detrimental. By the early 1900s large scale sintering agglomeration systems were in use . Figure 2.13 shows one such plant that helps demonstrate the large scale application of sintering by 1912. In the 1930s and 1940s, ore sintering included zinc, lead, lead sulfide, carbonates, chlorides, and precious metals.
Today iron ore agglomeration is the largest tonnage application for sintering, with plants operating at up 20,000 metric tonnes per day. For example, Figure 2.14 is a picture of a modern agglomeration facility which incorporates off-gas capture to reduce environmental damage. In such a facility, the iron ore fines are mixed with fluxes, carbon fuel, and water. The mixture is continuously fed onto trays or belts. As the conveyor moves through the sintering furnace, the mixture is heated to ignite the fuel and sinter the powder. Reaction waste consists of carbon dioxide, carbon monoxide, as well as nitrous oxides and sulfur oxides.
The so-called tumbler tests are usually used for testing material like coke, coal, iron ore pellets or tablets. They can be divided into drum tests and ball mill type tests. The latter type is used to derive both the Hardgrove Index and the Bond's Work Index, which are often used to classify the material friability as described in Sec. 3. They are generally more suited to coarse material. The Hardgrove Grindability test requires an initial size range form 595 to 1190 microns.
The Grace-Davison jet-cup attrition test is often used to test the friability of catalysts (e.g., Weeks and Dumbill, 1990; Dessalces et al., 1994). The respective jet-cup apparatus is sketched in Fig. 5. The catalyst sample is confined to a small cup, into which air is tangentially added at a high velocity (about 150 m/s). Some authors (e.g., Dessalces et al., 1994) assume that the stress in the jet-cup is similar to that prevailing in gas cyclones. With respect to fine catalysts, this type of test works as good as the impact test described above, but its applicability is limited to smaller sizes because larger particles tend to slug in the small cylinder. However, in the catalyst development, where at first only a little batch of catalyst is produced, this apparatus is an important friability test because it requires only a small amount of material (approximately 5 to 10 g).
The Fastmet is a continuous process which basically consists of a rotary hearth furnace where one or two layers of self-reducing iron ore pellets are placed. These self-reducing pellets are made from a mixture of iron ore concentrate, reductor (coal or coke), and binder. Unlike the other processes previously described, the Fastmet process uses a solid instead of a gas to reduce the iron oxide. The pellets travel through the rotary hearth furnace and are heated to 12501350C by burners placed throughout the length of the furnace. The rapid reduction rate of 12minutes is attributed to the high reduction temperatures and the close contact of the reductor and the iron oxide particles. DRI produced in this process is also unstable in air and must be briquetted to avoid reoxidation.
JKMRC has developed a slightly different method of estimating abrasion. Their method is similar to the standard laboratory Trommel Test applied for testing the abrasion of iron ore pellets and coke. In this test, 3kg of dry ore, size 55mm+38mm is charged into a horizontal cylindrical steel drum ID 0.30m 0.30m with lifter bars 2.54cm in height. The drum is rotated for 10 min at 53rpm (70% of the critical speed). The sample is then removed and screened to 38m. The cumulative mass percent passing each screen size is plotted. The mass percent passing 1/10th (T10) of the original size is taken as the abrasion parameter, Ta.Get in Touch with Mechanic