从钼酸钠溶液中选择性沉磷研究

Selective precipitation phosphorus from sodium molybdate solution

利用CaO-Na_(2)CO_(3)从钼酸钠溶液中选择性沉淀磷,考察CaO/P摩尔质量比、Na_(2)CO_(3)/CaO摩尔质量比、反应温度、反应时间、反应初始pH值、搅拌速度、钼酸钠溶液中P浓度、钼酸钠溶液中Mo浓度对P和Mo沉淀率的影响。结果表明,对于Mo 15 g/L,P 1.14 g/L钼酸钠溶液,控制CaO/P摩尔质量比为15,Ca_(2)CO_(3)/CaO摩尔质量比为0.6,沉磷反应温度308 K,反应时间120 min,反应初始pH值为9.5,反应搅拌速度120 r/min时,P和Mo沉淀率分别为99.04%,0.33%,沉磷渣中主要含Ca、O、C、P元素,主要物相为CaCO_(3)、Ca(OH)_(2)、Ca_(3)(PO_(4))_(2)。热力学计算数据可知,CaO-Na_(2)CO_(3)在钼酸钠溶液中高选择性沉磷过程,降低了CaMoO_(4)的生成几率,减少了Mo的共沉淀损失。

Calcium oxide-sodium carbonate was used to selective precipitation phosphorus from sodium molybdate solution.The effects of CaO/P molar ratio,Na_(2)CO_(3)/CaO molar ratio,reaction temperature,reaction time,reaction initial pH value,stirring speed,phosphorus concentration and molybdenum concentration on precipitation rate of phosphorus and molybdenum were investigated.The result showed that with sodium molybdate solution(P 1.14 g/L and Mo 15 g/L),the optimal conditions were further determined as follows:CaO/P molar ratio 15,Na_(2)CO_(3)/CaO molar ratio 0.6,reaction temperature 308 K,reaction time 120 min,initial pH value 9.5,stirring speed 120 r/min.Under above-mentioned conditions,the precipitation rate of phosphorus and molybdenum were 99.04%,0.33%,respectively,the precipitation residue mainly phase were calcium carbonate,calcium phosphate,calcium hydroxide,and mainly contains element were Ca,O,C,P.The analysis of thermodynamics calculation data known that calcium oxide-sodium carbonate is playing an important part in lowering chance to generate calcium molybdate for precipitation phosphorus processes.