一里坪硫酸镁亚型盐湖钾镁混盐转化-浮选中物相行为

加水比例及物相行为研究对硫酸镁亚型盐湖钾镁混盐转化制备软钾镁矾工艺具有重要意义。以柴达木盆地一里坪盐湖钾镁混盐为对象,采用“转化-浮选”法制备钾盐镁矾,研究了钾镁混盐初始及转化产生的物相行为。结果表明,初始物相光卤石、水氯镁石溶解速率最快,分解得到新物相氯化钾。初始物相钾盐镁矾及其转化得到的新物相软钾镁矾,溶解转化速率次之,加水比例高于0.40时,速率趋于平缓。初始物相氯化钠溶解速率始终最低。转化过程中,氯化钾只发生溶解行为,并未与软钾镁矾反应生成新物相硫酸钾。转化实验结果与理论计算结果吻合度高,相对误差低于4%,利用介稳相图理论计算能够指导钾镁混盐转化。同时,正浮选捕收剂对含钾物相的捕收吸附能力强于反浮选,钾的总收率达到66%。

Phase behavior of K-Mg mixed salt during transformation-flotation from Yiliping magnesium sulfate-type salt lake

Study on water-salt mass ratio and phase behavior during the K-Mg mixed salt transformation from magnesium sulfate-type salt lake is important for preparing Pic (Picromerite). Pic was prepared from the K-Mg mixed salt of Yiliping salt lake in Qaidam Basin by means of transformation-flotation. Phase behavior was researched which was the initial and new produced by transformation. The results showed that the dissolution rate of the initial phase Car (Carnallite) and Bis (Bischofite) was the fastest, and the new phase KCl (Sylvite) was obtained by decomposition. The dissolution and transformation rate of the initial phase Kai (Kainite) and the new phase Pic transformed from Kai was second, and while the water-salt mass ratio was higher than 0.40, the rate tended to be flat. The dissolution rate of the initial phase NaCl (Halite) was always the lowest. During the transformation, KCl only dissolved, didn’t react with Pic to form a new phase SOP (potassium sulfate). Experimental results of the K-Mg mixed salt transformation were in good agreement with theoretical calculation results, the relative error was less than 4% between them, the theoretical calculations of the metastable phase diagram could be used to guide the K-Mg mixed salt transformation better. Finally, the obverse flotation collector had stronger capacity for collecting and adsorbing the K-containing phase than the reverse, the total yield of K had been reached 66%.