Low Tungsten Solution Ion Exchange Method Improvement Program

With the awareness of the scarcity of resources has been widely recognized, to carry out comprehensive recycling of resources has become a consensus, therefore, the vast majority of tungsten smelting and processing enterprises have paid attention to the comprehensive recycling of resources and the gradual implementation of circular economy mode. For tungsten smelting processing enterprises, the control of effluent pollution treatment, and increase the total recycle of tungsten smelting enterprises is the focus of work.

In the tungsten smelting ion exchange process, due to the inherent nature of the exchange resin and exchange process characteristics, the resin adsorption of the solution of tungstate has a certain limit, and when the resin adsorption reaches saturation critical, the resin is very easy to leak, so after the exchange the tungstate ions are inevitably left in the liquid. The specific residual concentration is determined by the situation of post operation. If the degree of resin leakage is large, the concentration of tungsten in the liquid will be very high. Therefore, recycle is also of great necessity.

Common solution of low tungsten recycle method is mainly ion exchange method, relatively speaking, the ionic method for the recycle of low tungsten solution is less than ideal. Recently, some scholars put forward the process of ion method to improve, from the tungsten smelting ammonium paratungstate crystal mother liquor in one step recycle of tungsten and ammonia.

The pH of the liquid after the exchange is adjusted to about 8-10 by using sulfuric acid; The calcium in the liquid is recovered as the precipitating agent of the tungsten after the tungsten and ammonium tungstate (APT) crystallization mother liquor is recovered by using calcium oxide or calcium hydroxide, the reaction process is heated to 70 ~ 80 ℃; Fully stirred for more than an hour, the reaction terminated tungsten concentration 5mg / L, the formation of scheelite precipitate; filtered, the filter residue back to pressure cook leaching process, the waste sent to waste water treatment process.

By using the fully dissolved calcium ion system, the low concentration tungsten can precipitate with the form of scheelite, the precipitate rate of tungsten is high and the tungsten residue is less than 10mg/L. Heavy tungsten filter solution precipitation after entering the wastewater treatment system, the formation of white tungsten slag without precipitation after acid decomposition of complex processing, directly back to the pressure digestion process of scheelite, relative to the recycle of tungsten other process, this process not only saves the purchased new material, but also improve the recycle rate. At the same time, greatly simplifying the process, reducing the investment cost of equipment.

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