海盐卤水脱色制备氢氧化镁的试验研究

Study on Sea Salt Brine Decolorizing and Preparation of Mg(OH)_2

以辽宁某地海盐卤水为原料,进行脱色处理,以氨水沉淀镁制备氢氧化镁。比较过氧化氢、活性炭、次氯酸钠和次氯酸钙脱色处理获得氢氧化镁产物白度,以及次氯酸钙处理镁离子回收率,并对产物进行XRD、激光粒度分布分析。结果表明,次氯酸钙脱色效果最明显,次氯酸钠其次,活性炭和过氧化氢较差。以次氯酸钙为脱色剂,通过单因素变量法分析,确定适宜的条件为:添加量为37.5 g/L卤水,以稀硫酸调节p H值为10,温度60℃,时间60 min,镁离子回收率为93.41%;以氨水沉淀得到氢氧化镁产物,D50为1.462μm,白度为96.5%,达到HG/T 3607-2007中I类标准和HG/T 4531-2013行业标准MC-1-2要求。

Sea salt brine from Liaoning province was adopted as the raw material, by decolorizing processing and precipitation with ammonium hydroxide, magnesium hydroxide was prepared. Whiteness of magnesium hydroxide product obtained by decolorizing with hydrogen peroxide, activated carbon, sodium hypochlorite and calcium hypochlorite and recovery rate of magnesium ion dealt by calcium hypochlorite was compared, and the product was analyzed through XRD and laser particle size distribution. Result shows that effect of calcium hypochlorite decolorizing is most obvious, sodium hypochlorite secondly, activated carbon and hydrogen peroxide are poorer. Decolorizing with calcium hypochlorite, through the single factor variable method, the appropriate condition is adding content 37.5 g/L, adjusting pH value to 10 with dilute sulfuric acid, temperature of 60℃, time for 60 min. then precipitate to obtain magnesium hydroxide with ammonium hydroxide, and the grain size of D50 will be 1.462 μm, and whiteness will be 96.5%, which can reaches the standard of HG/T 3607-2007 type I and the industry standard HG/T 4531-2013 MC-1-2 requirements.