The researchers proposed a new two step ion exchange method for the preparation of high purity ammonium paratungstate. This method overcomes the shortcomings of low tungsten adsorption capacity, low concentration of crude sodium tungstate feed liquid, and large dilution of feed liquid in the ion exchange process using strong basic anion exchange resin, while maintaining certain advantages.
More details, please visit:
http://ammonium-paratungstate.com/index.html
Preparation of High Purity Ammonium Paratungstate by Two Step Ion Exchange
Use porous strong basic anion exchange resin (WA) to adsorb tungsten from the alkaline solution containing 40-50 g/L WO3, and use 1 mol/L sodium chloride solution as the desorption agent, the desorption solution contains 60-80 g/L WO3, acidify it to pH2.5-4 with sulfuric acid or hydrochloric acid as the feed liquid for next step of ion exchange, use acrylic weakly basic anion exchange resin (WC) to adsorb tungsten, and use 20% ammonia water as the desorption agent, desorption liquid contains 250-300 g/L WO3, evaporated and crystallized to obtain high-purity ammonium paratungstate.
