富硼渣常压碱解浸出液的净化及硼砂制备

以富硼渣为原料、Na OH为钠化剂,在常压碱解的基础上,考察了浸出液中杂质的产生、去除机理和去除效果.采用X射线衍射仪和扫描电子显微镜表征了富硼渣常压碱解及净化后的沉淀物和硼砂结晶产物的物相组成和显微形貌.结果表明:含硼浸出液中主要杂质是Ca2+和Si4+;Na HCO3对Ca2+的去除效果明显且Na HCO3的最佳添加量为3 g;浸出液p H值的改变对Si4+的去除效果明显,p H值为9.0时Si4+的去除率最高,可达到99%.实现"一步法"净化工艺,具有良好的去除杂质的效果.净化后的浸出液经蒸发、浓缩后获得了结晶良好的硼砂制品.

Purification of the Leaching Liquid from the Boron-Rich Slags by the Alkaline Leaching Method Under Ordinary Pressure and the Preparation of Borax

Based on the alkaline leaching method under ordinary pressure， the generation， removal mechanism and effects of the impurities in the boron leaching liquid were investigated， using NaOH as sodium treatment reagent and boron-rich slags as raw materials. Phase compositions and the morphologies of the precipitates after the purification and crystallization products of borax were analyzed by XRD and SEM. The results indicated that the primary impurities in the boron leaching liquid were Ca²⁺ and Si⁴⁺ impurity. The removal effect with NaHCO₃ for Ca²⁺ was obvious and the optimal amount of NaHCO₃ was 3g.There was great effect of the pH value of the leaching liquid on the removal of Si⁴⁺ when the pH value was 9.0， the removal rate of Si⁴⁺reached its maximum value of 99%. Thus “one-step method” purified technology which combines the process of removing Ca²⁺ and Si⁴⁺ impurity was achieved and with great removal efficiency. Well-crystallized borax was obtained from the purified leaching liquid after treatments of evaporation and concentration.