油酸钠作捕收剂时变性淀粉对赤铁矿及石英可浮性的影响

摘要

以油酸钠为捕收剂,以木薯原淀粉、取代度为0.026和0.21的羧甲基淀粉、取代度为0.0065和0 055的磷酸酯淀粉作为抑制剂,考察了赤铁矿和石英的可浮性重点研究了变性淀粉基团取代度对其抑制性能的影响浮选试验结果表明,原淀粉与变性淀粉对赤铁矿的抑制作用规律一致,提高变性淀粉的取代度可增强其对赤铁矿的抑制能力;对于Ca2+活化的石英,在较低的Ca2+用量时,原淀粉和变性淀粉均没有明显的抑制作用,但是随着Ca2+用量的增加,变性淀粉表现出一定的抑制作用、且取代度越高越显著.这种抑制作用与油酸钠、Ca2+及变性淀粉三者的用量有关.Ca2+以Ca(OH)+的形式吸附于石英表面,油酸钠或变性淀粉再与Ca(OH)+作用,如果油酸钠用量较大,全部Ca( OH)+优先与油酸钠作用,则石英被捕收;如果油酸钠用量相对较小,变性淀粉与剩余的Ca(OH)+作用,则对石英产生抑制作用 控制Ca2+和油酸钠的用量在最佳范围,增加变性淀粉的取代度可提高其在赤铁矿脱硅反浮选中的抑制性能.%Using sodium oleate as collector and cassava starch,carboxymethyl starch with degree of substitution of 0.026 and 0.21,and phosphate ester starch with degree of substitution of 0.0065 and 0.055 as depressant,the floatability of hematite and quartz were investigated,and the effect of degree of substitution of modified starches on capability of depression was mainly studied.Results of flotation tests show that the depressing effect of modified starches on hematite is similar with that of native starch,and the higher the degree of substitution of the modified starches,the stronger the depression capability.For quartz activated by Ca2+,both native starch and modified starches have no obvious depression at lower Ca2+ dosage,but with the increase of Ca2+ dosage,modified starches show a certain depression which increase with the degree of substitution.The depression was related to the dosages of the three reagents viz.sodium oleate,Ca2+,and modified starches.Ca2+ was adsorbed on the surface of quartz in the form of Ca (OH) +,then sodium oleate or modified starches reacted with Ca(OH) + If the dosage of sodium oleate is enough to react with all Ca(OH) +,quartz would be collected.If the dosage of sodium oleate is relatively small,quartz would be depressed by modified starches which reacted with the other Ca(OH) +.If sodium oleate and Ca2 + are added in optimum dosage range,with the increase of the degree of substitution modified starches would have more effective depression in reverse flotation of removal quartz from hematite.