复盐沉淀法分离稀土过程对硅走向的影响

对复盐沉淀法分离包头稀土精矿络合浸出液中稀土与非稀土元素过程中硅的走向进行研究。结果表明,浸出液的pH和稀土浓度对进入沉淀中二氧化硅的比率影响很小,进入沉淀中二氧化硅的比率随反应温度、反应时间和硫酸钠与稀土氧化物的质量比的增大而明显增大,溶液中悬浮的氧化硅及氟硅酸钠伴随着稀土复盐沉淀过程而共同沉淀;当硫酸钠过量时,氟硅酸钠能够与硫酸钠形成复盐而沉淀。经过复盐沉淀分离稀土与非稀土元素以后,还有80%多的硅保留在溶液中,在合成冰晶石过程中会参与合成反应。

Effect of Double Salt Precipitation Separation Process of Rare Earth on Silicon Movement

Silicon movement in complexation extraction solution during double salt precipitation separation process of rare earth concentrates was investigated. The results show that pH value of leaching liquor and concentration of rare earths have little influence on precipitation mass of silicon dioxide, and mass fraction of silicon dioxide rises with increase of reaction temperature, reaction time, and mass ratio of sodium sulfate to rare earth oxides. Suspending silicon dioxide in solution and sodium fluorine co-precipitate along with rare earth complex salt precipitation. When sodium sulfate is excessive, sodium silicofluoride precipitates with sodium sulfate to form double salts. After double salt precipitation separation of rare earth and non rare earth elements, more than 80% of silicon retaining in solution will be involved in synthesis reaction of cryolite.