Depressing capability of modified starches in the reverse flotation of quartz from hematite with cationic collectors
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摘要: 以十二胺為捕收劑，木薯原淀粉、取代度為0.026和0.21的羧甲基淀粉和取代度為0.0065和0.055的磷酸酯淀粉作為抑制劑，考察了赤鐵礦與石英的可浮性，重點研究了基團取代度對變性淀粉抑制性能的影響.結果表明：原淀粉、取代度0.026的羧甲基淀粉和取代度0.0065的磷酸酯淀粉對赤鐵礦有良好的抑制作用，而取代度0.21的羧甲基淀粉和取代度0.055的磷酸酯淀粉對赤鐵礦的抑制能力較弱；原淀粉和取代度0.026的羧甲基淀粉對石英有較強抑制作用，其他3種淀粉對石英抑制能力較弱.可見，低取代度的磷酸酯淀粉，在赤鐵礦陽離子反浮選脫硅中可作為較高選擇性的抑制劑.Zeta電位測定結果表明，特征基團取代度相對較高的變性淀粉，與赤鐵礦和石英作用后，礦物Zeta電位負值較大.變性淀粉的取代度越高，其伸展向溶液中荷負電的基團越多，使陽離子捕收劑通過靜電作用吸附于礦物表面，減弱了變性淀粉的抑制能力.Abstract: The floatability of hematite and quartz were investigated using dodecylamine as collector and cassava starch, carboxymethyl starches with degree of substitution (DS) of 0.026 and 0.21, and phosphate ester starches with DS of 0.0065 and 0.055 as depressants. The effect of DS on the depressing behavior of modified starches was studied. The flotation results show that native starch, carboxymethyl starch with DS of 0.026, and phosphate ester starch with DS of 0.0065 can strongly depress hematite, whereas carboxymethyl starch with DS of 0.21 and phosphate ester starch with DS of 0.055 weakly depress it. The native starch and carboxymethyl starch with DS of 0.026 can strongly depress quartz, whereas the other three starches are investigated possessed less depressing capabilities for quartz. The results reveal that a low-DS phosphate ester starch is a highly selective depressant in the reverse flotation of silica-containing iron ore with cationic collectors. The Zeta potential measurements exhibit that modified starches with higher DS can lead to lower Zeta potentials of minerals. Thus, the weakened depressing capabilities of modified starches might adsorb cationic collectors on the mineral surface via electrostatic attraction with negatively charged groups stretching into the solution.
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參考文獻
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