钙离子对煤泥浮选效果的影响研究

A study of the influence of calcium ions on fine coal flotation

针对浮选用水中钙离子浓度过高引起的浮选精煤灰分超标的问题,以棋盘井选煤厂浮选入料为研究对象,采用X射线衍射、浮选试验等方法,研究了浮选用水中钙离子浓度对煤泥浮选效果的影响,并探索了钙离子遮蔽剂对浮选效果的改善作用。研究结果表明:随着浮选用水中钙离子浓度的升高,浮选精煤灰分、产率和可燃体回收率呈升高趋势,浮选完善指标呈先升后降的趋势;钙离子浓度在一定范围内,浮选用水中的钙离子有助于煤泥浮选,当其浓度高于一定值后,将引起浮选精煤灰分超标;硅酸钠作为调整剂不能起到降低浮选精煤灰分的作用,而柠檬酸钠和碳酸钠作为遮蔽剂则能够实现降低浮选精煤灰分的目的,且柠檬酸钠的效果优于碳酸钠。当柠檬酸钠的用量为50mg/L时浮选效果最佳,此时浮选精煤灰分、产率、可燃体回收率分别为10.95%,63.91%,73.70%。

The problem faced by Qipanjing Coal Preparation Plant is that the flotation concentrate product is often seen to go over the specified limit in ash content because the process water has an excessively high concentration of calcium ions.To tackle the problem,the flotation feed material of the plant is taken as the object to explore the influence of calcium ions on fine coal flotation and the effects that can be ob-tained in improvement of flotation process through the use of maskant,using XRD and testing methods.Study result shows that the ash and yield of flotation concentrate and recovery of combustible matter all tend to increase with the rise of the concentration of calcium ions while the flotation perfect indice shows the tendency of first going up and then dropping down;the presence of Ca^(2+)with a concentration within a certain range is beneficial to fine coal flotation,but when its concentration goes above a certain value,the ash of concentrate product is caused to exceed the specified limit;no effect can be produced for re-duction of the ash of concentrate with the use of sodium silicate as modifying agent while the use of citric acid and sodium carbonate as masking agents can produce the expected result;in terms of effectiveness,the use of the former agent is better that of the latter one;when citric acid is used at a dosage of 50 mg/L,a best flotation result can be obtained,with the concentrate ash and yield and recovery of combustible matter being in this case,10.95%,63.91% and 73.70%,respectively.