中性三氯化铝浸取-EDTA-2Na测定多金属矿石中低品位萤石

Determination of Low-grade Fluorite in Polymetallic Ores by Neutral Aluminum Trichloride Extraction-EDTA-2Na

该方法适用于多金属矿中低品位萤石的测定。方法采用:试样先经含钙的稀乙酸处理,碳酸钙、其他可溶性钙与氟化钙分离,氟化钙在乙酸中溶解度极小,含钙乙酸溶解样品能够减少氟化钙在分离中的损失,残渣以中性三氯化铝溶液加热浸取,使氟化钙转化为氯化钙进入溶液中与硅酸钙盐等其他杂质分离。以三乙醇胺掩蔽铁、铝,巯基乙酸掩蔽重金属铋,用EDTA标准溶液滴定至绿色荧光消失为终点。

This method is suitable for the determination of low-grade fluorite in polymetallic ores. The sample was first treated with dilute acetic acid containing calcium, and calcium carbonate and other soluble calcium were separated from calcium fluoride. The solubility of calcium fluoride in acetic acid was extremely low, and the loss of calcium fluoride in separation could be reduced by dissolving the sample in acetic acid containing calcium. The residue was heated by neutral aluminum trichloride solution, so that calcium fluoride was converted into calcium chloride and separated from other impurities such as calcium silicate. Triethanolamine was used to mask iron and aluminum, mercaptoacetic acid was used to mask heavy metal bismuth, and EDTA standard solution was used to titrate until the green fluorescence disappeared.