Low Cost Tungsten Waste Treatment Method

The composition of tungsten waste is complex, difficult to extract and complicated to remove. This kind of APT is manufactured by traditional method with long technological process, narrow adaptability of raw materials, large investment in equipment, unstable products and poor economic benefits. In recent years, the preparation of ammonium paratungstate from tungsten waste has been explored and some results have been achieved.

Some scholars have published a method of recovering ammonium paratungstate from tungsten waste. The main contents are as follows:

1.Mix the raw material and sodium carbonate in the proportion of 1:0.6 by weight, sinter in the reflex furnace at 700 ℃, keep the melting or semi-melting state for 2 hours, and then cake out of the furnace. The water leaching: first grind the sintered material after cooling with ball mill and water into slurry; then pump the slurry into the iron trough to ensure tungsten content in the solution. Thirty g/L of water is added and heated to boiling for 1 hour, then filtered and washed by plate and frame filter press, and filtrate enters the next procedure. The washing liquid is returned to grinding section for grinding water and leaching water, and the filter cake is treated separately according to the valuable elements.

2.Pump the leachate into the trash removal bucket, heat and stir, adjust the PH value to 9.5 with 2N sulphuric acid; add 20 liters of saturated ammonium chloride and magnesium sulphate solution per m3 material liquid, stir for 1.5 hours; adjust PH to 8 with 2N sulphuric acid, boil for 30 minutes and stand for 4 hours; filter, wash and remove impurities by plate-frame press filter, and enter the next procedure. The washing liquid is returned to the grinding section for grinding water and leaching water, and the filter cake is treated separately according to the valuable elements.

3.Pump the filtrate into the chromium removal barrel after removing impurities, stir and heat it to 40 ℃, add sodium sulfide according to 2 times of molybdenum and chromium content, adjust the PH value to 8-10 with 2N sulfuric acid, heat it to boiling for 1.5 hours, filter the filtrate with plate and frame press, enter the next procedure, and sell the cake as chromium residue to the chromium salt factory;

The above recovery method has wide applicability, simple impurity removal procedure, short process flow, high tungsten yield, stable product quality, good physical and chemical properties, low equipment investment and low production cost.

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