Ammonium Paratungstate Prepared by Ion Exchange Method

Technology of ion exchange has brought significant technical progress in China's tungsten smelting, but it also has some defects at the same time. Especially wastewater generated from ion exchange has gradually become prominent with the environmental issues becoming more important. It mainly comes out in the following aspects:
1. Low feed concentration, and the large water consumption standout;
2. The low unit handling capacity of strong basic resin makes the small work of exchange capacity;
3. Wastewater is in large amount and difficult to deal with.

Ion exchange method base on Weak-base anion-exchange resin to prepare ammonium paratungstate is proposed in this paper. Specific steps as follows:
1. Tungsten concentrate was treated with alkali and alkaline sodium tungstate obtained;
2. Add acidic substances into the alkaline solution and heat for neutralization to get neutral sodium;
3. Dilute sodium tungstate to get pre-exchange solution;
4. Use Weak-base anion-exchange resin to adsorb tungsten;
5. Use of desorbent for desorbing Weak-base anion-exchange resin with tungsten, and get desorption;
6. Removing impurities in the desorption;
7. Evaporate and crystallize the solution to obtain ammonium paratungstate.

Using ion exchange method based on Weak-base anion-exchange resin for preparing ammonium paratungstate, can shorten the process, complete the tasks of removing impurities and transformation at the same time. Besides it got high recovery rate of tungsten with sample equipment, and effectively improves the concentration of tungsten in the feed solution of ion exchange process. Also it cuts down the amount of wastewater, and prepare qualified APT products ultimately.

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