How to Prepare Titanium Tungsten Silicon Composite Powder

With the continuous concern of haze, the control of air pollution has become more and more important. Nitrogen oxides are one of the main air pollutants and important precursors to induce photochemistry smog and acid rain. About 60% of them are discharged from coal-fired power plants, industrial boilers and cement plants.

Ti-W-Si composite powders used to prepare denitrification catalysts are mostly imported from abroad, which are not only expensive, but also not well matched with the technology of internal combustion coal. Therefore, it is of great significance to develop simple and effective composite powders. Our research scientists have adopted the following schemes to prepare titanium tungsten silicon composite powder.

After washing the qualified metatitanic acid, the concentration was adjusted to 200 g/L. The product was neutralized in 20% ammonia water, and reached pH 8.5 after neutralization. The neutralization process was maintained for 1 hour. The return pump was forced to circle stirring.

After neutralization, the analytic pure silica sol with 1.2% of the total quality of the finished product was added while stirring. Then, the ammonium paratungstate with the content of tungsten trioxide > 88.5% was added according to the calculation that tungsten trioxide accounted for 5% of the total quality of the finished product. After adding, the reactor is introduced into another reactor. The reactor is heated while stirring. The stirring is kept for 1 hour, and the temperature rises to 90 ℃. Then the reactor is heated and matured for 1 hour. After that, the filter cake was dried by a press, so that the moisture content of the filter cake was 45-55%.

After cake removal, the filter cake is broken and dried and burned in a continuous rotary kiln. The diameter * length * of the rotary kiln is 2.8m * 55m, the feed rate is 2.8t/h, the temperature of the end of the continuous rotary kiln is 355 ℃, the temperature of the kiln head is 520 ℃, and the temperature of the high temperature zone is 615 ℃. The oxygen content in tail gas of continuous rotary kiln is more than 12%, and the residence time of the whole material in the kiln is 11 hours. The material is discharged and cooled by continuous rotary kiln, then transported to the silo. The finished titanium tungsten silicon powder is crushed by micron mill.

The titanium tungsten silicon composite powder prepared by the above method has a crystal size of 14-16 nm, uniform dispersion, low viscosity, good fluidity, good water retention, easy formation of catalyst, high yield, high strength, high activity, stable quality, stable catalytic activity and long service life at 320-400 ~℃.

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