Ammonium trithiotungstate [(NH₄)₂WOS₃] is a kind of important glucosinolates metal ammonium salt, which can generate transition-metaldichalcogenide of WS₂ after the thermal decomposition, and has very well application in the synthesis of biological nitrogenase activity center - tungsten iron sulfur atom cluster compounds, semiconductor, superconducting, photoelectrochemical solar cell, battery, lubricant, electrochemical sensor, nanometer material, super capacitor, new generation of transistor and hydrogen storage and electrode material, and other respects. While it is also the precursor of coal liquefaction and heavy oil hydrogenation catalyst, as well as the raw material for manufacturing supported and non-supported type of tungsten sulfide hydrogenation catalyst.

 

Ammonium trithiotungstate can be prepared by the reaction of tungstic acid of ammonia solution and hydrogen sulfide gas, however, this method is harsh in operating conditions and the process is hard to control; moreover, the used hydrogen sulfide gas has the shortcomings of irritation, poisonous and cacosmia, which will cause serious damage to human body and the environment. So, an invention has pointed out an environmental friendly method to prepare ammonium trithiotungstate from the raw material of ammonium metatungstate (AMT), with the steps like bellow:

1. Weight a certain amount of ammonium metatungstate powder and add them into ammonium sulfide solution with a certain concentration to carry out a reaction, the molar ratio of W/S is controlled at 1:3~3.5, and the condition is optimized of 40~60°C, time for 1~2 hours;

2. Remove the ammonia gas by the way of vacuum or inlet inert gas into the reaction liquid, thus to release the generated ammonia gas out of the reaction system;

3. Add a certain amount of ammonium salt into the reaction liquid, then cool down to room temperature and stay to crystallize for 0.5~24 hours;

4. Filter, wash with a solvent, dry under the room temperature to finally get high purity ammonium trithiotungstate.

 

Vacuum or inlet inert gas into the reaction liquid in the process can play the role of promote the balance to the direction of generating ammonium trithiotungstate; meanwhile, the addition of ammonium salt will be benefit for the exhalation rate of ammonium trithiotungstate, and to get high purity product. The method which based on the raw materials of tungstate (such as ammonium metatungstate) and ammonium sulfide solution to produce ammonium trithiotungstate has the advantages of less waste discharging, no need to use poisonous hydrogen sulfide gas, sample process, environmental friendly and high yield (as high as 98% or even higher), thus to has very high industrial application prospect.