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用饱和法和等摩尔系列法研究了N263煤油溶液在pH1～13的范围内从钨酸钠水溶液中萃取钨的机理。当水相的平衡pH为1.0～1.1时,测得N263萃取钨的萃合比(WO3:N263,摩尔比)为3;当水相的原始pH分别为2.2～3.0、3.2～5.5、6.8～7.5之间和8.4,平衡pH分别为2.5～3.2、4.8～6.0、6.9～7.7之间和8.3时,测得N263萃取钨的萃合比分別为2.4、2、1.2和0.5;测定了萃余液中Cl~-离子的浓度,证实萃取是一个离子交换反应;并推得上述各pH范围内的萃取反应方程式。当水相原始pH>8.4时,萃合比<0.5,其原因可能是OH~-离子与钨进行竞争,也可能有(R_4N)_(x+2y)(OH)_x(WO_4)_y这类萃合物形成。在35±1℃恒温下,当水相的原始pH为2.3左右,萃合比为2.4时,测得萃取反应的浓度平衡常数lgK的平均值为12.5±0.3。
The mechanism of extracting tungsten from aqueous solution of sodium tungstate in the range of pH 1-13 by N263 kerosene solution was studied by the saturated method and the equimolar series method. When the equilibrium pH of the aqueous phase is 1.0-1.1, the extraction ratio of WO3: N263 (WO3: N263, molar ratio) is 3 when the equilibrium pH of the aqueous phase is 3. When the initial pH of the aqueous phase is 2.2-3.0, 3.2-5.5, 7.5 and 8.4, the equilibrium pH was between 2.5-3.2, 4.8-6.0, 6.9-7.7 and 8.3 respectively, and the extraction ratios of N263 extracted tungsten were 2.4, 2, 1.2 and 0.5, respectively. The raffinate The concentration of Cl - ions in the solution confirms that the extraction is an ion exchange reaction and deduces the extraction reaction equation for each of the above pH ranges. When the initial pH of the aqueous phase is> 8.4, the extraction ratio is less than 0.5, which may be due to the fact that OH ~ ions compete with tungsten, and (R_4N) _ (x + 2y) (OH) _x (WO_4) _y Extract formation. Under the condition of constant 35 ± 1 ℃, when the initial pH of the aqueous phase is about 2.3 and the extraction ratio is 2.4, the average concentration equilibrium constant lgK of the extraction reaction is 12.5 ± 0.3.