Composite cobalt - tungsten oxide powder is the main raw material for manufacturing cemented carbide powder, the finished product cemented carbide has been widely used in machinery manufacturing, oil exploration, military industry, aerospace and other fields because of its high hardness and density, wear-resisting and other special performance. 

 

Common methods for manufacturing composite cobalt - tungsten oxide powder by using the ammonium metatungstate (AMT) or metatungstate as raw material are like following:

Guaiacol, also known as adjacent hydroxyl benzoic ether or adjacent methoxy phenol, is the important fine chemical intermediate in spices, medicine, agriculture and dye and other industries, with its main utilizations as following:

1. Mainly used for the synthesis of vanillin, a rare type of broad spectrum of high-grade spice, the spices additive;

2. In the pharmaceutical industry, guaiacol is the intermediate of the expectorant cough medicine of potassium guaiacol sulfonate, and also the good fungicide;

3. It can be used as antioxidant to be applied in polymerization and food industry, and also can be used to determine copper, hydrocyanic acid and nitrite;

4. In the agriculture, 5 - nitro guaiacol sodium, which is formed through the steps of acetylation, nitration and hydrolysis from the raw material of guaiacol, is a kind of high efficient plant growth regulator that can quickly penetrate into the plant and promote the germination, striking root, growth, and bearing fruit of plant. 

 

Most of guaiacol productions are through chemical synthesis method, while the traditional production process exist serious environmental pollution, large cost and many useless by-products and other shortcomings. Therefore, the development and utilization of non-toxic, harmless and pollution-free production process of environmental friendly catalyst is the inevitable developing trend of chemical process in the future. 

 

Studies have pointed out one kind of supported solid catalyst with the active component of ammonium metatungstate (AMT) to catalyze alkylation reaction (which is also called as catechol with methanol gas solid phase alkylation reaction) of gasified catechol and methanol, and thereby to synthesize guaiacol. The properties of this production process are as follows:

1. The solid catalyst is taking tungsten ad active center, and the loading weight may be 5 ~ 15% of the total mass;

2. The catalytic reaction temperature is 533~573 k; 

3. The molar ratio of catechol and methanol is 1:5;

4. The preparation of the catalyst is using the traditional impregnation method, which is impregnating the 40 ~ 60 sieves of established silica particles in a certain amount of ammonium metatungstate aqueous solution for some time, then drying, and roasting under 533~773 k  for 3 hours to finally get ammonium metatungstate catalyst;

5. The production process with low production cost, low toxic and corrosive of raw materials and catalyst, little environment pollution.

Tungsten nitride is a kind of new catalytic material, which shows an excellent performance in hydrogenated desulfurization and denitrification; also, it can not only prevent the sulfur pollution caused by industrial catalyst presulfurization, but also have high selectivity in the hydrogenolysis of heteroatomic ring. 

Currently, the barium-tungsten which is widely used in the magnetron is limited, due to the strong electronic back in the device which makes the consumption of BaO is too fast and thus to result in the decrease of the device’s life; moreover, the secondary electron emission ability of it is difficult to meet the requirement of high power microwave device. Furthermore, due to the radioactive problem of Th, it is already suitable for some of the high power magnetron ThO₂ cathode. Study found that even through the rare earth - molybdenum metal ceramic cathode materials has a stable secondary electron emission performance, but its thermal emission performance is poor, and requires a higher temperature in magnetron start up, and thus to limit its using in the magnetron.