2019年8月15日星期四

GY Chelating Collector

GY chelate collector is the pioneer of the flotation industry in recent years, it is chelate class and fatty acid mixture, there are many categories.

The collection of tungsten ore is mainly made up of benzoic acid and fat collector, GYB and GYR. GY chelating collectors are popular, mainly because they have good selectivity and strong collecting ability. It has good flotation performance for wolframite and scheelite or other nonsulfide etc.. The wolframite and scheelite tungsten ore can be separated without mixing and flotation, which is suitable for the present situation of "lean, thin, miscellaneous and mixed" of the tungsten ore resources in China.

GY chelating collectors image

The most famous applications of GY chelating collector is Hunan shizhuyuan polymetallic ore mining. As everyone knows, shizhuyuan polymetallic ore mining industry is recognized as the most difficult dressing in China, their composition is complex, and the size of the mineral inlay is very fine, and the average size is only 0.01 millimeters - 0.03 millimeters, when grinding ore, it is very difficult to master and difficult to operate. Shizhuyuan tungsten ore is mixture of scheelite and wolframite, the ratio is 3:7, associated with more than 20 minerals, a variety of mineral components are mixed together, and very difficult to separate.

How to separate and recycle shceelite and wolframite mixture? In 1999, Zhang Zhongliu and several other scholars used GY series of chelating collector test in shizhuyuan. According to the mineralogical characteristics of shizhuyuan tungsten molybdenum bismith fluorite polymetallic ore, using the modified water glass selective inhibition of gangue minerals such as fluorite etc., using lead salt to activate wolfram minerals, mixed flotation of wolframite and scheelite with new type of GY chelate collector, the scheelite concentrate is obtained by heating and selecting the mixed coarse ore concentrate. Moreover, the wolframite concentrate is obtained by flotation of the selected tailings with GY collector.

The industrial test results show that the WO3 can reach 70.07% and the total recovery of tungsten can reach 81.62% when the ore is 0.47% WO3 and the GY concentrate is recycled by using a collector. Compared with the traditional 733 oxidation paraffin wax method, the process is simpler and the recycle rate is greatly improved, in addition, 99% of the CaF2 has entered the floating tailings and created favorable conditions for the recycle of fluorite from the tailings. The success of the new flotation process of scheelite and wolframite by GY method is mainly reflected in the effective separation of scheelite and fluorite in mixed flotation, improve the scrambler flotation and inhibition of the active recovery of wolframite in the selection. It can be said that the application of GY series chelating collectors is the savior of many low benefit mines on the verge of bankruptcy. 

In recent years, based on GY series chelating collectors, scholars have also developed many new GY series of drugs and combinations to keep up with the times, such as CF-GY shizhuyuan method, provide many effective mining scheme for increasing tungsten resources in China.

If you have any inquiry of tungsten, please feel free to contact us:
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Wolframite and Scheelite Mixed Flotation -- Shizhuyuan Method

Hunan Shizhuyuan Tungsten Polymetallic Mining Area is a large deposit with a variety of minerals, with up to 143 kinds of mineral varieties.

It is mainly composed of tungsten, tin, bismuth and molybdenum, and is rich in fluorite, copper, lead and zinc , sulfur, iron, gold, silver, beryllium, niobium, tantalum and other minerals, the economic value is difficult to estimate.

Shizhuyuan ore mineral embedded in the complex size of the mineral industry is recognized by the most difficult mineral processing. The ratio of wolframite and scheelite ore is 3:7, and a lot of fluorite, molybdenum and bismuth are associated with it. In the early stage, shizhuyuan using the traditional method of heating and flotation to 733 oxidation of paraffin soap as a collector, the total recovery of tungsten ore is only 40-50%, a large number of waste of resources to make the economic benefits of the mine hesitant.

shizhuyuan method image

In order to get rid of the waste of tungsten resources at an early date, at the beginning of this century, Guangzhou Nonferrous Metals Research Institute, Beijing Institute of mining and Changsha Nonferrous Metallurgy Design Institute and other units jointly tackle key problems, based on the GY chelating collector, a new method of mineral processing, such as molybdenum bismuth and other floatable and bismuth sulfur, and CF-GY combined with the new process of flotation tungsten, a new method of dressing combined with the new technology of CF-GY combined method known as "floating wolfram, shizhuyuan method".

The method is based on the heating flotation method, using highly selective chelating collector CF and GYB mixed flotation wolframite and scheelite and recycle of wolframite slime, a set of processes can realize the difficult technical problems of wolframite and scheelite flotation and difficult separation by flotation of calcium containing minerals. A new flotation process of molybdenum bismuth and other floatable - bismuth sulfur floating - combination inhibitor molybdenum bismuth separation - oxidation bismuth sulfur separation was developed by separating molybdenum, bismuth and so on; Tungsten coarse concentrate combined with sodium sulfide and water glass heating cleaning process, a new process for fluorite flotation by high intensity magnetic separation with combined inhibitors and selective collectors, it provides technical guarantee for the exploitation and utilization of fluorite resources in ores.

The ore of shizhuyuan polymetallic mine in WO3 containing 0.25%-0.45%, belong to low grade complex ore. The industrial test showed that the shizhuyuan tungsten dressing method, the recovery rate can be increased to about 77.70%, nearly 30% increase over the old flotation method, do not underestimate this 30%, for the enterprise, it was tens of millions of economic income.

The recycle rate of tungsten has been greatly improved, and the cost of ore dressing has decreased because of the “shizhuyuan” method, it is a revolutionary breakthrough in the beneficiation technology of tungsten, tin, molybdenum and bismuth in China. It has set a benchmark for many low efficiency mines and pointed out the road.

If you have any inquiry of tungsten, please feel free to contact us:
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Tungsten Carbide Preparation by Sodium Tungstate

Tungsten carbide (W2C) is composed of a tungsten and carbon black compound, six crystal, metal luster, hardness and diamond are similar, extremely difficult to melt.

Tungsten carbide is a good conductor of electricity and heat, mainly used in the production of cemented carbide materials. The traditional tungsten carbide process, must be go through the production of ammonium paratungstate, tungsten powder preparation and carbonation and many other processes, the production cost is high and the process is lengthy. In order to reduce the production cost of tungsten carbide, the approach is to reduce the process from mineral raw materials to product manufacturing processes.

There are many methods for the preparation of tungsten carbide. For example, high temperature melt extraction, carbonization and reduction by aluminum, tungsten carbide is directly obtained from high-purity tungsten concentrates. These methods are simple, crude and effective, but the temperature requirements are particularly high. They need to be realized by the high temperature calcination equipment above 2000 °C, and some enterprises are difficult to achieve. Therefore, we have to explore another new shortcut for the direct reduction of tungsten carbide from sodium tungstate.

tungsten carbide powder image

Sodium tungstate is an intermediate transition from tungsten concentrate to APT. The chemical composition is Na2WO4·2H2O crystal or colorless crystalline powder. Some scholars used calcium acid as carbon source to synthesize tungsten carbide with sodium tungstate.

In the experiment, the sodium tungstate powder was first dried at 120 °C in a vacuum drying chamber for 2 hours, the sodium tungstate powder without crystalline water is obtained, with carbide powder grinding in a planetary ball mill for 15 minutes at the same time, and then the columnar mass is obtained by the briquetting mechanism, after weighing, the graphite crucible was placed in a vacuum reduction furnace for reduction and carbonization. The reduced products obtained by reduction remove the calcium oxide by acid washing.

2NaWO4+6CaC2=W2C+6CaO+2Na2O+11C

After reduction of sodium tungstate by calcium carbide, can obtained purer main phases W2C, tungsten and carbon can produce two kinds of tungsten carbide, WC and W2C. WC is a near normal compound. It can hardly dissolve carbon or tungsten. Therefore, in order to get the WC, the W2C should be obtained with calcination twice, the calcination temperature is 1600 °C, the heat preservation time is 2h. In the two times carbonization process, increasing the heating rate and prolonging the moisture retention time are beneficial to the growth of crystal and decreasing the cooling rate, which is beneficial to refine the grain size of tungsten carbide. Finally, the compound is formed by two times carbonization at high temperature to produce more pure tungsten carbide powder.

The process of converting tungsten sodium tungstate to tungsten carbide eliminates the need for ammonium paratungstate, relatively, it saves a lot of process and cost. Compared with the high temperature melt extraction carbonization and aluminum thermal reduction method, it requires a lower temperature of the reaction furnace, in general, is a law-abiding approach. In industrial practice, however, this shortcut has not attracted much interest, the reason is probably: 1. It is not as straightforward as the high temperature heat reduction method; 2. Tungsten produces tungsten carbide although the cost is slightly higher, its ultimate quality is better controlled.

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Zinc Tungstate Photocatalytic Degradation of Four Chlorophenol Wastewater

Four chlorophenol is a major component of biological pesticides, wood preservatives, dyes and rust removing agents.

Four chlorophenol is also used in Asia, Africa and South America to prevent and control schistosomiasis; In addition, biological treatment of municipal wastewater and industrial waste water also contains chlorophenols. Four chlorophenol wastewater is a kind of three toxic agent, which is carcinogenic, teratogenic and mutagenic. It is easy to cause serious pollution to the environment and is difficult to decompose, therefore, the United States Environmental Protection Agency (EPA) has included it in the list of 129 priority environmental control pollutants.

In recent years, the application of semiconductor photocatalysis technology in environmental management has received extensive attention, among them, the tungstate semiconductor photocatalyst, with its non-toxic and high photocatalytic activity, has gradually replaced the early physical and chemical treatment methods with poor efficiency and high cost, while the zinc tungstate tungstate is four chlorophenol wastewater sniper.

zinc tungstate photocatalytic degradation image

Compared with the traditional physical and chemical methods, the advantage of treating four chlorophenol wastewater with zinc tungstate is simple operation, mild reaction conditions, non-toxic and environmental protection, and the effect is outstanding.

Some scholars used zinc tungstate doped with fluorine to synthesize zinc tungstate photocatalyst, in the test of four chlorophenol, four chlorophenol is firstly adsorbed on the surface of nano ZnWO4, when ZnWO4 absorbs light greater than or equal to the energy of the band gap, photogenerated holes and electrons are produced, four chlorophenol was degraded simultaneously in two ways. During the reaction, the hole and electron move toward ZnWO4, and the photogenerated hole reacts with them directly to form hydroxyl radical, photogenerated electrons are trapped by oxygen molecules adsorbed on the surface to produce superoxide anions, superoxide anion is further protonated to form hydroxyl radicals, and hydroxyl radicals react directly with benzene rings, resulting in CO2 and H2O.

The photocatalytic activity of four chlorophenol wastewater can be obviously improved by using zinc tungstate as photocatalyst, the results show that the total degradation rate of four chlorophenol wastewater reaches 95% after visible light catalysis of 12h, this shows that sodium tungstate has a very good effect on four chlorophenol, and this is also the gospel of the vast population of water pollution areas.

If you have any inquiry of tungsten, please feel free to contact us:
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