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本文通过溶液化学的讨论,定量解释了黑钨矿表面在纯水中荷负电的原因,是由于Mn~(2+)、Fe~(2+)的优先溶解。根据溶液平衡计算,绘出了钨酸锰和钨酸铁的溶解度对数图,由此得出MnWO_4理论上的等电点为2.8,FeWO_4理论上的等电点为2.0。实验测定天然钨锰矿的等电点与MnWO_4的理论值一致,天然黑钨矿的等电点为2.5,处在FeWO_4与MnWO_4的理论等电点之间,并且,数值大小与Mn/Fe有关。根据绘出的浓度对数图,还讨论了在pH=6.0～9.5,黑钨矿表面ζ电位出现近零电点区域的原因。最后认为,靠静电力吸附的阴离子型捕收剂及通过与铁、锰离子键合化学吸附的阴离子型和络合型捕收剂,都将在黑钨矿近零电点区域实现最佳浮选。
In this paper, through the discussion of solution chemistry, the reason why the surface of wolframite is negatively charged in pure water is explained quantitatively because of the preferential dissolution of Mn ~ (2 +) and Fe ~ (2+). According to the solution balance calculation, the logarithm diagram of the solubility of manganese tungstate and iron tungstate is plotted, which shows that the theoretical isoelectric point of MnWO 4 is 2.8 and the theoretical isoelectric point of FeWO 4 is 2.0. The isoelectric point of natural wollastonite is in agreement with the theoretical value of MnWO_4. The isoelectric point of natural wolframite is 2.5, which lies between the theoretical isoelectric points of FeWO_4 and MnWO_4, and its value is related to Mn / Fe. Based on the logarithm plot of the concentration plotted, the reason for the near zerode zero point in the zeta potential of wolframite at pH = 6.0-9.5 was also discussed. Finally, it is concluded that the anionic collectors adsorbed by electrostatic force and the anionic and complex collectors chemically bonded by iron and manganese ions will all achieve the best floatation in the near-zero point region of wolframite selected.