High purity boric acid product was prepared by complex crystallization using industrial boric acid as raw materials. Impurities were selectively separated from boric acid by using that way. Different kinds of analysis methods, such as complex formation titration.thermogravimetry (TGA) ,ICP-AES,and UV analysis were used to characterize the purity and performance of boric acid. Influences of the factors,such as kinds and dosages of oxidant and complexing agent and crystal series,on the purity of boric acid during the process of purification were investigated. Optimal conditions were obtained as follows;2% (volume fraction) H2O2 was added in saturated solution of boric acid,stirred and hot-filtrated,0. 2% (mass fraction) aminocarboxyl chelating agent (H2Y) was added in the filtrate at 80 ℃ ,and then hot-filtrated,slowly cooling to form boric acid crystal,after recrystallization and drying,the 99.99% boric acid was produced.%以工业硼酸为原料,利用络合结晶分离技术对硼酸中杂质进行选择性分离提取,制备高纯硼酸产品,通过化学滴定分析、电感耦合等离子体原子发射光谱( ICP - AES)、紫外分光光度法、热重分析(TGA)等对产物的纯度和性能进行表征.考察了氧化剂与络合剂的种类和用量、结晶的级数等因素对硼酸产品纯度的影响,确定的最佳工艺条件为:硼酸饱和溶液中加入2％(体积分数)的H2 O2,搅拌反应后热过滤,滤液中加入质量分数为0.2％的氨羧络合剂,80℃下反应,热过滤后缓慢降温结晶,经重结晶分离获得的硼酸产品的纯度达99.99％.
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