Tungsten carbide valve ball or called tungsten carbide ball valve is converted from conventional stopcock. It uses a ball to start and stop by sphere running around the stem axis. Compared with conventional valve, valve ball has many advantages, such as simple structure, excellent tightness, light in weight, lower material consumption, smaller installation size, smaller volume within a certain nominal diameter, smaller driving moment and easy operation for controlling, which becomes one of the most rapid developing of valve gradually in recent years. Tungsten carbide ball valve in the pipe main role is cut off, distribution and change the direction of media flow, other special designed ball valve structure can achieve flow adjustment function.

Tungsten carbide ball (WC-Co) with high precision we discuss here has been widely used in valve ball and ball seat for oil drilling, deep-sea drilling, which is also the most critical component of oil pump. Due to the harsh conditions in oil drilling industry, especially in some sand drain, heavy oil well, high pressure oil well, which contains water, diverse gas, wax, sand and some materials with high corrosivity, the pump need to pump oil from hundreds or even thousands of meters of strata extracted. It requires that the ball valve and ball seat has excellent tightness, wear resistance and corrosion resistance (pumping the ball, with rear seat evacuated to an absolute pressure 0.36kgN / cm2 or less, in the 10s the absolute pressure values do not change).

Ion exchange method, specific steps are carried out as follows:
1. Heating ammonium paratungstate(APT) to 130~140℃, and keep the temperature for 1~8 hours;
2. Transfer the formation of step 1 into slurry, and boiled to 80~100℃ for 2~6 hours to form ammonium metatungstate (AMT) solution;
3. Concentrate and crystallization, filtrate to separation, and then dry to get AMT crystal.

Electrodialysis method, the implementation steps are as follows:
1. Add APT into the anode chamber, and electrify;
2. When the electricity passes by, the ammonium ions go into the cathode chamber through the anion exchange membrane, and the concentration of AMT ion in the anode chamber increases;
3. Release the AMT solution from the cathode chamber;
4. Concentrate and crystallization, filtrate to separation, and then dry to get AMT crystal.

Shallow thermal decomposition - resin exchange method, the steps are as follows:
1. Place the APT in the enamel plate, and put them in a constant temperature oven at 240℃ heated for 25~30 minutes;
2. Remove the reactants, slowly pour into pure water of 95℃ with stirring;
3. Add L type resin when the majority of solid is dissolved, control pH value between 3~4, and stir for 30min in an environment of constant temperature;
4. Filter he mixture through a stainless steel screen to remove resin and debris;
5. Lay aside the filtrate for 12 hours, then vacuum filtration to remove insoluble impurities and tungsten compounds;
6. Heat and condense to crystallization, and drying by 50-60℃ air for 2 hours to obtain AMT crystal.

Ammonium metatungstate (AMT) is an important intermediate product of tungsten metallurgy, a white crystal or yellow powder which is easy to dissolve in water, but insoluble in alcohol. AMT can be used in preparing tungsten, alloy steel, fire proof fabric, etc. and also be used for ceramic industry. It’s also used in the manufacture of various petrochemical catalysts and other tungsten compounds which is the raw material of catalysts based on tungsten. There are many ways to generate AMT, such as tungstate, ion exchange, thermal decomposition method and so on. This paper, we would like to introduce some methods that preparing AMT base on material of ammonium metatungstate (APT).

Neutralization method – take APT and nitric acid as raw materials to generate AMT, the specific steps are as follows:
1. Add ionized water n and citric acid into APT to form a mixture that concentration of WO₃ 12% ~ 30%;
2. According to the ratio of APT: nitric acid equals to 1:20, adding nitric acid which the concentration is 3% to 5% into APT slurry;
3. Control solid-liquid ratio at 1: (3~4), and pH controlled in 2~4, heating and dissolve to make the relative density of the solution about 1.18~1.20. Then heated to 80~90℃, keep the temperature and pH value constantly, stir for 4h, aging for several hours;
4. Concentrate the solution until the WO₃  content is about 50%, filtering to remove the insoluble substance, and keep concentrating, then cooling down to 80℃ and drying get AMT.

Cyclohexanone is organic compound, it is carbonyl carbon atom including the six-membered ring saturated cyclic ketone; it is colorless and transparent liquid, it containing traces of phenol. Cyclohexanone impurities are yellow. Cyclohexanone has a carcinogenic effect; it is mainly used in industrial organic synthesis of raw materials and solvents. Cyclohexanone is an important chemical raw materials, it is widely used in nylon, caprolactam and adipic acid intermediate principal. It is also an important industrial solvent, such as for paints, in particular for nitrocellulose, vinyl chloride polymers and copolymers or methacrylic acid ester polymer paint.

Tungsten trioxide catalytic preparing cyclohexanone are affected by many factors. We analyze them by the table in order to have further investigations on the effects for different polymorphs WO₃ catalyst preparing cyclohexanone yield:

As we can see from the table above, catalyst WO₃ form is changing with calcination temperature,, but the change of the cyclohexanone yield is not obvious, which can describe the reaction of crystalline WO₃ has little effect.

Tungsten trioxide thin films has optical properties, electrical properties, magnetic properties, chemical properties, mechanical properties, thermal properties, etc., it has a variety of properties and thus be applied in many fields, for example, it is used as electrical film, optical film, hard film corrosion film, lubricating film, decorative film, packaging film. Among the many film material, tungsten trioxide thin films have good electrochemical performance, so it has been widely used, such as discoloration smart windows, gas sensors, pH meter and so on. At the present, many researchers have studied tungsten trioxide thin film material, especially the photochromic electricity and electrochemical properties.

Preparation steps:
1. Putting the base W into the alkoxide solution in dry N₂ atmosphere, pulling out of the base by the electric;
2. Drying and removing excess organic solvent in an atmosphere of dry nitrogen coating, the process should be about 30min;
3. Ensuring sufficient hydrolysis to form gel films in humidity atmosphere of 30%, so that W-OR (organic material) can become into W-OH and R-OH (finally evaporated), this process can keep1h;
4. Heating the thin film, the treatment consists of two processes: the first step is heating it at 200 ℃, keeping it 30min; the second step is heating it at 430 ℃ , and removing the residual organic solvent, so as to form thin film of tungsten trioxide.

The study shows that tungsten trioxide thin film density is lower than the material density (7.16g / cm³), it is 0.57 before the heat treatment, and it becomes 0.64 after annealing at 180 ℃, which leads tungsten trioxide thin film to form microcrystalline structure.

Seismic tungsten wire was produced by doping K, Si, Al and other elements. It is widely used in the lighting system at vibration environments. Seismic tungsten wires were divided into three types. First kind is seismic tungsten wire doping with Si, Al and K elements and this type has good organizational structure and high-temperature sag resistance value is small. Second kind is seismic tungsten wire doping small amount of Fe or Co elements whcih based on Si, Al, and K elements doped, and this seismic tungsten wire has better high temperature resistant, sag resistance and other performance; third kind is tungsten rhenium alloy wire which produces by doping Si, Al, and K elements and small amount of Re into tungsten powder. Tungsten rhenium alloy wire has good organizational structure, high recrystallization temperature, resistivity, elongation and other good properties.

Seismic tungsten wire production processes are as following:
1. Mix the raw material and the doping elements evenly by proportionately, and dried. Then placed them in a hydrogen furnace occurs reduction reaction by sintering. The raw material can be used are ammonium paratungstate (APT), ammonium metatungstate (AMT) and tungsten blue (TBO), but the study showed, blue tungsten oxide has high chemical resistance, good doping effects, large specific surface area and excellent fast rate, and other good performances, so it can produce seismic tungsten wire with better performances.
2. The reduction calcined powder after wash by acid and then drying, pressing, sintered.
3. The sintered blank after thermal processing obtains seismic tungsten filament.

In the preparation process, there are basically three methods for Si, Al, K, and other elements doping. One is mixing tungsten powder and doped powder, namely solid - solid doping. Although this method has simple process, but it is difficult to make doped powder evenly distributed in tungsten powder and will bring some problem on the subsequent processing; the second is the matrix solution and the doping solution, namely liquid - liquid doping. This doping method has complex processes which are not suitable for industrial production; third doping method is powder and doping elements mashing solution doping that solid - liquid doping, it not only has simple process steps, produced seismic tungsten wire has a good performance which widely used in the industry.

Seismic tungsten wire having good seismic performance not only has a good seismic performance and impact properties at room temperature and high temperature, also has a high temperature anti-sag property and good winding performance. Seismic tungsten wire is mainly used in lighting system for vibration environment, such as cars, motorcycles, tractors and other vehicles lighting, but it also can be applied to the military lighting field and as a heating wire used in aerospace field engine. Its use is widespread.

Seismic tungsten wire was produced by doping K, Si, Al and other elements into tungsten powder. After studies found that adding K and Al into tungsten powder seismic tungsten wire can not be successfully produced, but the product has excellent processing performance. And doping in the tungsten powder with K and Si obtained seismic tungsten wire has ordinary seismic performance. Only doping with K, Si and Al, you can achieve seismic tungsten wire which has excellent performance. This is because that doping Si is conducive to maintaining oxidation layer’s sponginess and permeability of water during the reduction process, so that the doping will more uniform, but also conducive to obtaining the necessary potassium. Doping Al can improve the potassium content in tungsten powder to obtain high-quality seismic tungsten wire. Doping with K can obtain potassium bubble. The dispersion of potassium bubble which can significantly reduce the low-temperature brittleness of tungsten wire, reduce splitting, making seismic tungsten wire get the best seismic performance.

With the development of science and technology, every industry has strict quality requirements of stringent seismic tungsten wire. To produce excellent performance seismic tungsten wire need to optimize production processes and process improvements, but also need further research and experimentation, making seismic tungsten wire can have broad market prospects in various fields.

There are large number types of tungsten heteropoly acid. A method for preparing silicon tungstate from ammonium paratungstate, the specific steps are as follows:
1. Conversion process: select ammonium paratungstate, heating to 90~100℃, stirred with a speed of 60~120r/min, adjusting pH value among 2~4, then ammonium metatungstate (AMT) obtained;
2. Mach silicon: adding silicate into the transformed AMT, then adding ammonia, and adjust pH value to 7-8, heated to 90~100℃ with stirring, reaction time for 2~4.5 hours, pH 9 ~ 14, ammonium silicon tungstate;
3. Cation exchange: reaction in exchange column, the rate is 30~100L/hour;
4. Evaporation and concentration: filter to remove the insoluble in solution when the specific gravity of organic solution is 2g/cm³; continue to evaporate to get silicon tungstate until it reaches 3g/cm³.

The advantages of that method are as following:
1. Reasonable process, good quality of the product, no pollution, and suitable for large scale industrial production especially;
2. With important promotion value;
3. A kind of environmental friendly green catalyst widely used in petrochemical, chemical catalysis and medicine field;
4. Laid the foundation about producing and developing heteropoly acid and salt centered with other elements.