Tungsten Oxide

In the production, sometimes for some reason lead to part of the APT products in the classics or physical performance on the failure, may also occur in the production process a small amount of ammonium paratungstate waste recycle, which are recyclable. Recycle of unqualified ammonium paratungstate method is mainly after the dissolution of the filter, and recrystallization, for this reason, the APT is dissolved at a higher temperature directly with ammonia as a solvent, however, APT solubility in aqueous ammonia is limited, resulting in dilute solution concentration, it takes for a long time to dissolution. Therefore, the modern industry began to use of APT thermal decomposition into ammonium metatungstate for recycle. Thermal decomposition of the working mechanism is to control the appropriate temperature, calcined APT can be converted to ammonium metatungstate (AMT). According to the high temperature decomposition performance of APT·4H 2 O, when heated APT·4H 2 O in t...

Ammonium paratungstate (APT) preparation is an important part of smelting tungsten, whether it is using chemical precipitation method, ion exchange method or extraction method, it all have to go through the process of ammonium trioxide to produce qualified APT. APT is an important tungsten intermediate product, the higher the purity the greater the value, so APT preparation process is also the further purification of tungsten. Commonly used method for preparing ammonium paratungstate is evaporation crystallization method, neutralization crystallization method and frozen crystallization method. Evaporation crystallization method is heating evaporation solvent, so that the solution from unsaturated to saturated, continue to evaporate, the excess solute will be crystal precipitation, called evaporation crystallization method. This method of technology and equipment is simple, easy to large-scale, this method technology and equipment is simple, easy to large-scale, at the s...

Ammonium paratungstate (APT) is an important tungsten intermediate product, mainly with white crystals. It have flakes, needles and strips three kind, used in the manufacture of tungsten trioxide or blue tungsten oxide, TP,  also used for manufacturing ammonium metatungstate and other tungsten compounds. Because the production of tungsten oxide, morphology and particle size of tungsten powder has genetic relationship with APT, so the production process is not only to the tungsten APT purification, but also to control the crystal morphology and particle size of paratungstate tungstate. In the 1950s, in the book "Tungsten and Molybdenum Metallurgy" by A.H rickman, used the reaction 5(NH 4 ) 2 O·12WO 3 ·nH 2 O to describe the APT formula, used the evaporation crystallization process to get n = 5 flaky crystal, and used the acid neutralization process for n = 11 needle crystal. After that in China are all using this view, that of ammonium tungst...

Ammonium paratungstate (APT) preparation is an important part of smelting tungsten, whether it is chemical precipitation method, ion exchange method or extraction method,they all have to go through the process of ammonium trioxide to produce qualified APT.   APT is an important tungsten intermediate products , the higher the purity the greater the value, so APT preparation process is also the further purification of tungsten. Neutralization is one of the most commonly used manufacturing method of para-ammonium tungstate, and it's settlement with hydrochloric acid and (NH 4 )  2   wo 4  solution, precipitation crystallization of ammonium paratungstate, and the energy consumption is small, crystallization speed is fast, easily to recovery the fine particle APT. The neutralization method is carried out in a reaction tank with a liner rubber. Heating with hydrochloric acid and (NH 4 )  2 WO 4  solution, ammonium paratungstate crystalliz...

Evaporation crystallization method is the most commonly used method of preparation of ammonium paratungstate , this method of technology and equipment is simple, easy to large-scale, have a certain role in the purification at the same time,it has been favored by industrial production. When the ammonium tungstate solution heated, the ammonia concentration decreased, (NH 4 ) 2WO 4  solution concentration gradually increased, ammonium paratungstate crystallization, the reaction is: 12(NH 4 )2WO 4 ==5(NH 4 )2O·12WO 3 ·5H 2 O+14NH 3 ↑+2H 2 O In industrial production, the degree of evaporation crystallization is generally based on the amount of molybdenum allowed in the solution and the product. There are usually two ways of batch intermittent operation and continuous crystal operation. The batch intermittent operation was carried out in a jacketed heated stirred tank, and a solution of (NH 4 ) 2WO 4  having a density of 1.16-1.28 g / cm3 was added to the reactor an...

Ammonium paratungstate (APT) is an important part of tungsten smelting, whether it is using chemical precipitation method, ion exchange method or extraction method, they all have to through the process of ammonium trioxide to produce qualified APT.  APT is an important tungsten intermediate products , the higher the puritythe greater the value, so APT preparation process is also the further purification of tungsten. Freezing crystallization method is one of the most commonly used methods for the preparation of ammonium paratungstate, which is the use of liquid ammonia to freeze the APT, so called frozen crystals.  The freeze crystallization method was carried out in a liquid nitrogen cooled vacuum drier, and the ammonium tungstate solution was poured into an enamel plate pre-filled with liquid nitrogen (the volume ratio of ammonium tungstate solution to liquid nitrogen was 1: 2), stirring it and then   crystallized water and APT at the same time, Along w...

Ammonium paratungstate (APT) is an important tungsten intermediate product, not only in the purity and process requirements, as well as crystal grain size and crystal distribution requirements. Seemingly negligible some of the objective factors often play a key role in the final product often For these reasons the difference between the least, lost thousands of miles. 6. The impurities in the solution: As the solution P, As, Mo, Si and other impurities easily adsorbed on the crystal growth of the active point, hinder the crystal growth, but also makes the ammonium paratungstate grain thinning, make the quality of deterioration, and easy to enter the product during the evaporation crystallization process, affecting product quality, and even lead to product failure, so in the crystallization process, should take the control of crystallization rate, improve the concentration of NH 4 Cl in ammonium tungstate solution, stirring and washing agents and other methods, to achieve th...

Ammonium paratungstate (APT) is an important tungsten intermediate product, mainly white crystals, there are two kinds of flakes or needle-like, used in the manufacture of tungsten trioxide or blue tungsten oxide tungsten powder. The quality of tungsten products depends largely on the chemical purity of APT, particle size and particle size distribution. APT quality standards from the domestic manufacturers, the process and chemical purity are almost the same, but the production of APT products vary widely, this is because APT is a system engineering, not only the purity and process requirements, as well as crystal grain size and crystal distribution requirements, seemingly insignificant on some of the objective factors often play a key role in the final product is often because of these reasons the difference between the least, lost thousands of miles. There are lots of influence factors of ammonium tungstate, mainly include: the temperature of the solution, the degree...

From dressing industrial progress of history suggests that mineral processing reagents application significance is self-evident.  Since its discovery in 1924 xanthate has the function of collecting sulfide ore, the development of the flotation industry started by leaps and bounds, the inundated mineral processing reagents has been invented and created with a steady stream. The crystallization crystallization method and the neutralization method produce the crystallization mother liquor in the preparation of APT. These mother liquor contain not only impurities but also some WO 3 . In order to improve the total recovery of tungsten, the mother liquor is often recovered once again in the industry treatment, as to which method should be based on the previous process and the composition of the mother liquor to use, usually available alternative methods are conversion method, solution extraction and ion exchange method. Conversion method is commonly used in the ...

Wolframite and scheelite mixed tungsten ore flotation is a worldwide difficult problem, because of the black and white tungsten composition structure is very different, conventional flotation method at room temperature and heating method is not ideal. Would there have a more effective way to realize whether black and white tungsten mixed flotation? Chairman MAO once said: “There is a way, it just hasn’t been found.” He also said: “Paths are made by men.” And actually it does. After many years of industry practice, our country's scholars found that the focus on black and white tungsten study is mixed flotation collector, the flotation is strong while the collector is strong, scholars use the collector as the breakthrough point, make many light avenues. In 70s and 90s, Chinese scholars use 731 + 733 combination of black and white mixed tungsten ore flotation collector, 731 and 733 to mix ratio of 10:1, the collector has the advantage of source is easy to obtain, the dis...

Wolframite and scheelite are different with the same name, there are all “w” but their body structure are not the same, so their beneficiation method is different, black tungsten gravity commonly used the separation method, scheelite commonly used flotation process. After years of development, our country each has a solid industrial foundation of beneficiation technology in wolframite and scheelite tungsten ore flotation. From a single scheelite recovery of scheelite in bed or recovery of wolframite from single black tungsten deposit is relatively easy. But why there is a certain type of skarn deposits made mistake like, they try to make the black and white tungsten together under the same roof, so the deposit is called "black and white mixed tungsten deposit. Mixed black and white tungsten ore flotation is a worldwide difficult problem, in this type of ore deposits, the black and white tungsten are in fine grained disseminated separately symbiosis in the strata, alth...

In the flotation system, two or more collectors are used in combination, and by combining the collector and producing synergistic effects, such tungsten ore flotation collector is known as combination collector in practice. It has been proved that many combination collector has better and more effective flotation results than the use of a single collector, and there are divergent views on the causes. For the study of the mechanism of the combination collector, there are scholars think that the combination collector also has a significant chelating effect, it refers to the combination collector and mineral surface of the metal between the combination collector metal's special affinity caused by the real chemical reaction. The result of this reaction is the formation of insoluble, stable metal chelate.  The scholars of South China University used the quantum chemistry ab initio algorithm to calculate the molecular model of benzohydroxamic acid and benzyloxamic acid. T...

Inhibitor as well as known retarder, it can retardant or reduce the chemical reaction speed of the material, the function is the same as the negative catalyst. Tungsten flotation inhibitor can be divided into two types: Organic inhibitor and inorganic inhibitor.  The most commonly used for modified sodium silicate inorganic inhibitors, metal ion+sodium silicate, ammonium salt, sodium silicate, sodium silicofluoride, pyrophosphate, etc. They each have their own strong points. Here introduces a kind of inorganic inhibitors tungsten flotation-modified sodium silicate. Modified sodium silicate is  through the water glass for modification, acidification or the use of other agents in combination with the way to achieve the water glass can improve the inhibitory effect of calcium-containing gangue minerals purposes. Modified sodium silicate is the activator after decomposition of sodium silicate, it can produce a large number of single molecule silicate, the singl...

Commonly used tungsten flotation collector can be divided into anionic collector, cationic collector, amphoteric collector and nonpolar collector and complexing or chelating collector dosage form five categories, these collector is known as the fatty acid, phosphoric acid, chelation, amine, petroleum and so on. Full of beautiful collectors are always dazzling, objectively speaking, every collector has different strengths and weakness, for example, the fatty acid collector has strong ability of flotation but the ability of selectivity is poor. The selectivity of chelating collector is good but it is expensive. The selectivity of phosphoric acid, sulfonic acid, amine are good but the flotation ability is a bit poor and there exists environmental pollution. In great abundance of choices, it says suitable is the best, but it is hard to choose the right thing in one in a million, after continuously experiment again and again, people found that is also can go with “mix and match” sty...