生产食品级和药用氯化钾主要采用工业级产品通过进一步纯化的方法制备得到。盐湖工业氯化钾制备方法是采用浮选剂进行浮选制备,因此存在浮选剂残留和部分重金属超标的情况。经测定所用盐湖工业氯化钾样品中,铵和铅的质量分数分别为1.698×10^-4和1.63×10^-5。为了制备食品级氯化钾,采用猪骨为原料,以磷酸为活化剂制备得到了比表面积为147.26 m²/g、碘吸附值为297.5 mg/g的活性生物猪骨炭,实验结果表明,用10 g的活性猪骨炭和商品炭分别对1 L的氯化钾溶液做吸附处理,活性猪骨炭吸附后溶液中各离子含量均符合GB 25585—2010《食品添加剂 氯化钾》的要求,成功制备了食品级氯化钾。

Food grade and medicinal potassium chloride are mainly prepared by further purification of industrial grade potassium chloride products.The industrial potassium chloride from salt lake is prepared by flotation agent,so there are some problems of residual flotation agent and some heavy metals exceeding the standard.By determination of industrial potassium chloride samples from salt lake,the mass fractions of ammonium and lead are 1.698×10^-4 and 1.63×10^-5.In order to prepare food grade potassium chloride,the activated biochar with the specific surface area of 147.26 m²/g and the iodine adsorption value of 297.5 mg/g was prepared by using pig bone as raw material and phosphoric acid as activator.Then,1 L potassium chloride solution was adsorbed by 10 g activated pig bone biochar and commercial carbon,respectively.Results showed that after the adsorption of activated pig bone biochar,the contents of all ions in the solution met the requirement of Food Additive Potassium Chloride,GB 25585—2010,and food grade potassium chloride was prepared successfully.