富硼渣钠化法制备硼砂过程中的影响因素

X射线衍射分析(XRD)表明,富硼渣中的硼组分主要以Mg2B2O5形式存在,而钠化渣中的硼组分以Na4B2O5和NaBO2晶相形式析出.对钠化渣进行磨细、水浸、过滤、结晶等操作,可最终制得硼砂晶体.采用化学分析和XRD等方法研究了热处理温度、碳酸钠加入量、钠化渣细度对硼浸出率的影响.当钠化渣在温度为650℃下保温1.5h,碳酸钠加入量为理论量的2.3倍,钠化渣粒度小于74μm时,硼的最大浸出率可达76.04%.

Study on Influencing Factors on Preparing Process of Borax from Boron-rich Slag

Boron-rich slag could be separated from ludwigite by pyrometallurgical method.Na_2CO_3 was added to the melted slag to change the existing form of boron,then the Na_4B_2O_5 and NaBO_2 in crystalline phase were precipitated from the Na_2CO_3-modified slag at high temperature as shown by XRD analysis.Sodium borates thus turned into solution via the water leaehing,grinding,filtering and crystallizing of Na_2CO_3-modified slag and,as a result,borax could be precipitated from the solution at room temperature.Effects of the adding dose of Na_2CO_3,heat-treatment temperature and particle size of Na_2CO_3-modified slag on the leaching rate of boron were investigated by chemical analysis and XRD.It was found that the actual adding dose of Na_2CO_3 is 2.3 times as great as the theoretical one if the Na_2CO_3-modified slag is treated at 650℃ and held for 1.5 hr,and that the highest leaching rate of boron can be up to 76.04% if the particle size of Na_2CO_3-modified slag is less than 74 μm.