High-Purity Ammonium Paratungstate Prepared From Tungsten Ore with High Molybdenum

With the decreasing of high-quality tungsten ore, tungsten ore with high molybdenum has increasingly become an important raw material in metallurgy of tungsten, and it requires higher technology in separation of tungsten and molybdenum. A new ion exchange method based on three column series which is used to removing molybdenum in tungsten ore or fine mud to get pure ammonium paratungstate in low cost is presented in this paper. Three column ion exchange adsorption has a high capacity in adsorption and removing molybdenum effectively (the rate beyond 95%), reduce the number of resin regeneration and tungsten loss, also the consumption of auxiliary materials has been cut down.



Steps are as follows:
1. Ball grounding tungsten ore or fine slime, leaching with alkali, filtering, and concentrated to obtain sodium tungstate crystal;
2. Dissolve in and filter the sodium tungstate, then vulcanization;
Control WO₃ in sodium tungstate solution at 130-180g/L, pH value less than 12, adding Na₂S solution in accordance with S₂^- 1 ~ 8g/L, and then with adjust pH value to 7~10 by dilute H₂SO₄, heating to 60-80℃ and insulation for 0.5 to 5 hours;
3. Remove molybdenum by ion exchange;
4. Remove sulfur from sodium tungstate;
Inlet air into sodium tungstate under the condition of alkaline, and heating to make S₂^- to turn into sulfur or sulfide precipitation;
5. Remove impurities by method of ion exchange, then desorbs tungsten with ammonia and ammonium chloride solution to prepare ammonium tungstate;
6. Evaporate and crystallize to get APT.