Potassium doped in round aluminum tungsten is the raw materials in electric light manufacturing, electronic devices in ANTIDROOPING tungsten filament and vacuum spray plating tungsten hinge wire and other high-temperature heating body and resistance to high temperature components. A method for preparing potassium doped in round aluminum tungsten strip is introduced in this paper.

Specific steps:
1. Choice of materials: select special size of ammonium paratungstate distribution with crystalline in FSSS for 40 to 50μm and loose density in 2.1~2.5g/cm³ as raw material;
2 Mild reduction ammonium paratungstate: the raw material mild reduction in furnace in seven ranges of temperature to produce special intermediate ammonium tungsten bronze (ATB). Among them: seven ranges of temperature are 300, 360, 400, 420, 430, 450, 420℃, rate of hydrogen flow at 0.2~0.3m³/h,;
3. AKS doping: mix wet ATB with potassium silicate, aluminum nitrate solution dissolved in deionized water, and make potassium, silicon, aluminum adopted in the pores of ATB, doped ATB formed;
4. Direct reduction: ATB directly reduction in seven temperature reduction furnace a and fine grain tungsten powder B with FSSS 2.2 ~ 2.6μm generated; coarse grain tungsten powder D with FSSS 3.3~4.2μm generated in the same way;
5. Pickling: washing fine grain tungsten powder B, coarse tungsten powder D respectively with hydrochloric acid of concentration 6~8%, hydrofluoric acid of 6~8% to remove dopant and impurities;
6. Mixing powder: mixing the fine particles of tungsten powder B, coarse grain tungsten powder D according to a certain weight ratio after pickling;
7. Cool down and static pressure;
8. Pre-sintering: 120 ~45min under temperature of 40℃;
9. Vertical melting: directly electricity to sintering under the protection of hydrogen gas.

Ammonium metatungstate is an important tungsten compound, mainly used in petroleum cracking, organic synthesis, nitration and other industries as a catalyst. The dosage of ammonium metatungstate is increased with the rapid development of oil refining. The traditional way crystallization to prepare ammonium metatungstate from ammonium paratungstate has high investment, energy consumption and unstable quality of the resulting product, poor solubility, can not meet the need of catalyst.

Ammonium paratungstate used as raw material to leaching out the solution, then dilute ammonium metatungstate solution turns into a concentrated solution, and spray and drying the concentrated ammonium metatungstate solution to prepare ammonium metatungstate crystal.

Specific steps are as follows:
1. Leaching out the wet ammonium paratungstate: to wet ammonium paratungstate content 5 ~ 10% water as raw material and mix with nitric acid (HN0₃) to prepare dilute ammonium metatungstate solution;
2. The dilute ammonium metatungstate prepared by the step 1 goes through many times of static and precipitation, filtration and heat to concentration and then obtain the concentrated ammonium metatungstate solution;
3. Spray and dry, make the material dried quickly into ammonium metatungstate powder.
Its advantages lie in:
1. There is no need to roasting, so the rotary furnace equipment is useless, therefore to reduce investment of fixed;
2. The actual recovery rate of ammonium metatungstate increased;
3. Slowly and continuously feeding overcomes the problem of low solubility of ammonium metatungstate, to get ammonium metatungstate solution with high content of tungsten trioxide;
4. Use wet ammonium paratungstate product as raw material saves the process of drying and packing, to achieve the purpose of saving energy and reducing cost.