How to produce ammonium paratungstate using tungsten-contained soft waste material? The researchers proposed a method for producing ammonium paratungstate using tungsten-contained soft waste material. The method has the characteristics of short process flow, low investment in equipment, high productivity and yield, low cost of recycling, and no waste liquid that pollutes the environment.
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A Method for Producing Ammonium Paratungstate Using Tungsten-contained Soft Waste Material
Step One: Mix tungsten-contained soft waste material with dilute ammonia water, leached at 0.2-0.6 Mpa and 120-200 °C for 1-3h; the dilute ammonia water (concentration 4-15wt%) in the material is calculated as NH3, and the tungsten in the tungsten-contained soft waste is calculated as WO3, the molar ratio of the two is 2.5-4.5:1; wherein, the tungsten-contained soft waste is the leaching residue generated during the production of ammonium metatungstate.
Step Two: The material liquid after the leaching reaction in Step One is sent to the filter, and the residue is filtered.
Step Three: Send the filtrate obtained in Step Two to the evaporator, evaporate and concentrate it at a temperature of 50-100 °C until the density of the mother liquor in the slurry is 1.02-1.10 g/mL, and finally obtain ammonium paratungstate crystals by solid-liquid separation.
