The experimental principle of mixer settler extraction metal tungsten
ion exchange resin as a polymer with polar group of compound, it does not dissolve in water, acid, alkali and any solvents, the structure can be divided into three parts: ( 1) Insoluble polymer scaffold; ( 2) On the skeleton of polar group ( Fixed ion) ; ( 3) Polar groups can ionization ion ( The ions) 。 With gay ion in the solution to the ion exchange. According to the ion exchange resin with the exchange of the different functional group, ion exchange resin can be divided into strong acid, weak acid, strong alkali, weak alkali, aojiang, gender, reducing oxide resin. Know,
the first ZhangWenXian data in tungsten hydrometallurgy ion exchange method system, the current process of ion exchange resin generally choose strongly basic anion exchange resin, the resin on the reaction is the reaction with anion selective in the solution to the following:
resin and ion exchange reaction, different ions have different exchange capacity, called exchange potential. Ion exchange method is to use resin exchange potential of ions in the solution, the purification and separation of different materials in the implementation. Now most of the leaching of coarse tungsten smelting factory sodium tungstate solution contains a lot of oH - , and the current is generally selected ion exchange technology exchange resin 201 X 7 ( Cl- ) Strongly basic anion resin. This research adopts the D201 - W ( HCO3- Type) Ion exchange resin method transformation and purify the crude sodium tungstate solution, using the same resin for adsorption material liquid ion affinity of different purification. Adsorption material liquid in the process of adsorption of high concentrations of various substances on anion exchange resin can be down. The experiments on the resin exchange reaction equation is:
to remove impurity phosphorus and arsenic in crude sodium tungstate solution, silicon, aluminum, etc. , also inspect ion exchange is one of the important symbol of success. In this study did not examine the impurity behavior of aluminum, if leachate contains more aluminum can consider to choose the precipitation or compact mobile adopts literature in a fluidized bed method of recycling aluminum. Experiment has chosen the representative impurity phosphorus and arsenic, studied the behavior of impurities.
actually tungsten solution chemistry is more complex, when these mixed impurities, is more complex, because these elements can form of a variety of different with tungsten heteropoly acid or heteropoly acid salt.
it is generally believed that when water � � liquid pH > 8, tungsten mainly monomer is tungsten acid radical form, when pH13 phosphorus is P043 exist. Arsenic aqueous solution system is more complex, in water solution, arsenic can with five price, trivalent two valence, another potential can also affect the existence form of arsenic. In aqueous solution, the existence of arsenic forms are similar to those of phosphorus. By mol percentage of pentavalent arsenic and pH of the diagram can be concluded that when pH > 13, impurities in the solution is ASO3 - in the form of arsenic ion
due to adsorption material liquid in the test of alkalinity is greater than 20, ion exchange adsorption of tungsten in the material liquid to monomer wO42 - There, not combined with phosphorus, arsenic, etc. This is to achieve in the exchange of tungsten impurities possible at the same time. The experiment is based on WO42 - Unlike other ions in the aqueous solution properties of, use of WO42 - The resin affinity than SO43 and PO43 - substantially Such as anionic, can preferential adsorption on the resin so as to realize and ASO43 and PO43 impurity ion separation.
so the impurities in the resin on the reaction equation is:
single column experiment systematically examines the process of adsorption and desorption conditions of various factors, including the exchange adsorption, adsorption exchange of contact time, and the adsorption material liquid concentration and basicity on the influence of adsorption, learn suction contact way, contact time and the influence of the composition of the desorption agent on the desorption, and studied the behavior of impurities.
as a result of adsorption material liquid concentration is larger, single column test found in the process of adsorption resin from start to cross between saturated liquid after a large number of tungsten acid radical ion adsorption, has not been a waste of the raw material increased the tungsten loss, and the top wash water washing process have tungsten loss. So in order to improve the resin adsorption effect, and try to increase the economic efficiency, reducing the loss of tungsten experiment of adsorption resin leakage after wear, wash process adopts the method of two columns in series. Experiments by the method of series column can maximum adsorption tungsten acid radical ion, make wash effluent of the process of adsorption and top of tungsten loss is basically zero. In order to expand the application scope of this study, further improve the adaptability to production, string column experiment was carried out.
by comparing string of adsorption column experiment the average exchange capacity and adsorption capacity of single column test of high and low, the adsorption effect of removing impurity, top washing process, and the change of desorption impurity concentration in the effluent to examine several aspects, such as string column experiment is similar to the effect of a single column, prove that bunch of column adsorption test whether can achieve the desired purpose.
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