The reduction method of tungsten trioxide (WO₃) is also known as tungsten trioxide carbonization, the method can be used to restore high-quality ultrafine tungsten powder, the process is needed by the mixer, pellet mill dryer and two rotary kiln components.

Firstly, we take the tungsten trioxide (mass fraction, 84%) and carbon black powder (mass fraction, 16%) to mix the grains in order to have a diameter of 3mm ball, and then to have two successive reduction in a rotary kiln. Continuously during the reaction through a series of intermediate products:
WO₃ → WO_2.9 → WO_2.72 → WO_2.0 → W → W₂C → WC.

Heating WO₃ in the first furnace at 1247 ℃ in N₂, the heating reaction products are WO_2.72, mixture of WO₂ and W, and the ultra-fine grain nucleation occurs in the intermediate product of the transformation. The process WO_2.72 and WO₂ are due to a sharp contraction in the volume of fine grain, and the transition time of WO_2.72 transferring to WO₂, which has a significant increase in density. Two compounds promote grain growth WO₂ (OH) is not formed in the case of materials containing carbon black. Fine WO₂ particles do not thicken into ultrafine grain. Secondly, putting kiln at 1500 ℃ in the rotary, and hydrogen atmosphere ultrafine W are directly restored. Finally, we usually add a small amount of grain growth inhibitor to prevent the ultra-fine carbide grain growth.

Experiments show that in the direct reduction process, original tungsten trioxide and carbon black play an important role in the performance characteristics of tungsten reduction. the size of carbon is reduced in the order of C → B → A. When the original tungsten trioxide particle size is 2.60 micron to 1.80 micron, the tungsten grain size reduction is hardly affected by the particle size of carbon black, in this case of the tungsten powder particle size are reduced about 0.50 microns. When using a particle size of 1.00 micron, tungsten trioxide fine particles and carbon are reduced, the reduction of tungsten particle size is 0.36 micrometers, this depends on the original particle size reduction of tungsten trioxide, and the size and reduction of tungsten powder are prepared by WC- CO alloy.

In addition, edge button lost after the failure of the original gage role DTH drill, drill itself will begin to wear occurs, which also shows the life of buttons directly affects DTH drill service life. Related researchers through a lot of experiments summarized two mechanisms carbide abrasive wear of buttons, one is tungsten carbide (WC) and cobalt (Co) subjected to a uniform wear, similar to polishing action phase, another is cobalt (Co) is first removed, and tungsten carbide (WC) particles are pulled and caused scratch; surface fatigue wear caused by tungsten carbide buttons and rock slide occurred relatively arising and produced alternating load; Adhesive wear occurs at the hardness of tungsten carbide ball and rock hardness are approximately equal state, and tungsten carbide buttons have plastic deformation and rock relative motion between the two separated and then bonded to each other, in this process carbide particles are stripped and blemishes.

2. Button Break: In the form of failure to wear mentions the concept of middle button and the edge button so that button break can be divided into the middle button break and the edge button break. Furthermore, the edge button plays a protective effect on the life of the drill DTH greatest impact. Generally, DTH drill bit end faces and buttons oblique angle of 35 °, due to the action of force is mutual, at the time of impact rock drill, eccentric impact occurs, while when the rotary drill bit cutting edge button by friction of rock, two forces together to produce the side teeth of the roots of a certain moment, the force long-term effect of such cycle prone to cracking source internal button, leading edge button fracture. However, the middle button does not produce eccentric impact, which the impact mainly caused by the friction of rock and button produced the bending tensile stress.

3. Button Drop: Button drop and smash is also occurred. The main reasons of tungsten carbide DTH drill buttons drop includes button drill bit not in the same horizontal plane at a fixed time, causing all the balls can not contact with the teeth of rock, the individual button floating ball practice involved, tensile stress wave, and the buttons has been pulled out; DTH drill cuttings by air blowing to wear during operation, resulting in part of the button exposed, thereby reducing the button bit rigid binding force; The last reason is DTH drill button arrangement when the interference does not fit properly, resulting in insufficient fastening force some button loss occurs.

Although tungsten carbide buttons have higher hardness and impacting resistance, it is brittle and has poor wear resistance. In the process of drilling, the high temperature of the high-speed collision with rock buttons occurrence arising will make carbide hardness decreased and crushed quartz particles made of a soft but opposed the hard phase transition occurs. Therefore, tungsten carbide buttons used for DTH drill failure will directly affect the drilling efficiency. The failure mode of tungsten carbide buttons used for DTH drill includes wear (grain wear, surface fatigue wear and adhesive wear), buttons break, buttons drop and so on. Next, we will discuss these failure modes one by one.

1. Wear: This is the commonest failure mode of tungsten carbide buttons used for DTH drill, which can be specifically divided into grain wear, surface fatigue wear and adhesive wear. Due to the conditions of DTH drill is usually strict, such as underground, down hole operation. The DTH drill buttons except impact and rotary crushing rock and rock cutting wear occurs, the air flow generated by the drill cuttings will be written to the buttons wear, especially in some high pressure DTH drill bit. DTH drill carbide buttons can be divided from the inside edge of middle and edge button, the middle button is mainly used for crushing rock, while the edge button not only involved in rock crushing,  but also plays an important role is to protect the drill bit to prevent the surrounding rock drill bit itself wear. Since DTH bits during the rotary cutting rock edge against the outer edge of the button so large line speed, it will be wore earlier so that the size of the edge is larger than the middle ones, but the speed of wearing is higher than the middle.

At present, people have been able to prepare different pore sizes of porous tungsten trioxide and using a variety of methods by materials that containing a large hole, mesoporous and microporous, or only two of the pore size. These materials have important applications in catalysis, selective separation and sensors; however, the porous material with a foam shape is generally more fragile and friable. Tungsten trioxide is a transition metal oxide that is widely studied because of its unique properties. In addition, the doping tungsten trioxide complex also has a catalytic effect. It means that tungsten trioxide morphology and structure of the desired application function has a direct relationship.

Steps:
Preparing dimensional network structure WO₃ containing mesopores by concentrating hydrogen peroxide (H₂O₂), methanol, over-acid and polyvinylpyrrolidone (PVP) solution. Preparing WO₃ mesh structure by using optical microscopy, scanning electron microscopy (SEM), powder X- ray diffraction (XRD), thermal gravimetric analysis (TG), high-resolution transmission electron microscope (HRTEM) and N₂ adsorption isotherms (BET) technology after firing.

Conclusions:
1. Optical microscopy and SEM photograph show this shape of the foam cube mesh structure regardless of WO₃, which are relatively stable calcinations that are supported by the nature of the performance.
2. Magnified SEM image shows that the wall mesh structure is assembled from nanoparticles made of WO₃ after calcination.
3. XRD diffraction analysis shows that WO₃ is amorphous foam before calcination, and is orthorhombic crystals after calcination. As PVP structure, it has the advantage of inducing inexpensive agents and stable solution.

Ammonium metatungstate (AMT) is a tungsten compounds with high molecular weight and water-soluble, which is easily dissolved in water, the solubility of it can reach 100g/mL at room temperature. It can be prepared from the material of ammonium tungstate by the method of Bipolar Membrane Electrodialysis (BEMD).

Electrodialysis method uses the effect of electric field, makes water which is in the two sides of bipolar membrane dissociated into H⁺ and [OH]^- then directional moved to both sides of electrode, and entered into the liquid chamber (the salt chamber) and alkali chamber respectively. Electrodialysis method is widely used in the field of chemical, light, metallurgy, papermaking industry and so on.

The preparation process of AMT by the method of electrodialysis which is using ammonium tungstate or ammonium paratungstate as raw materials is performed as bellows:
1. Add ammonium paratungstate into anode chamber, when an electric current passes by, water dissociated into two forms--H⁺ and [OH]^- and directional moved to both sides of electrode under the action of strong electric field, and then respectively enter the liquid chamber (the salt chamber) and alkali chamber;
2. H⁺ ions enter the salt chamber to combine with WO₄^- and then will not go into alkali chamber ever again; ammonium ions move to cathode chamber through the exchange membrane, thus cause the concentration of ammonium metatungstate increased;
3. [OH]^- moves into alkali chamber through the anion exchange membrane to combine with ammonium ions which is continually moved in and no longer went into the anode chamber;
4. With the process of electrolysis carrying out, ammonium ions decreased and hydrogen ions increased continually in the salt chamber, thus cause the pH value of the solution in salt chamber decreased continuously;
5. Finally, ammonium metatungstate solution is released from the cathode chamber, and AMT generated.