Abstract: In the acid pulp leaching solution of non-ferrous metals, there are often fine silicate minerals, which are charged on the surface, can form a stable system in the acid pulp, and it is difficult to settle, which leads to the extraction and electrodeposition process. Moreover, most non-ferrous metal hydroxides are insoluble in water and cannot neutralize the surface electricity of silicate minerals by adjusting pH, which also brings difficulties to the separation of silicate minerals in acidic systems. Polyacrylamide (PAM) is an effective flocculant, which is widely used in water treatment and paper making. Polyethylene oxide (PEO) is widely used in pharmaceutical industry, oil mining, light industry textile and other fields, and has been shown to be effective in flocculating silicate minerals. Polystyrene sulfonate (PSS) has a large amount of negative charge, which can effectively reduce the surface potential of silicate minerals in acidic pulp. Tannic acid (TA) can make the polymer compound associate, thereby increasing the apparent length of molecular chain and improving its flocculation performance. Therefore, in order to solve the problem of silicon removal in acid leaching pulp, the flocculation and sedimentation behavior of fine kaolinite in acid system was investigated by using -2000 mesh (6.5 μm) kaolinite as raw material in this work. The results showed that the flocculation performance of polyacrylamide was stronger than that of polyethylene oxide. Coagulant aid PSS can further improve the flocculation effect. The flocculation effect of PAM and PEO was the best when combined with 100 g/t PSS. The effect of TA on coagulation was not obvious. Using the focused beam reflectance measurement (FBRM), it was found that the size of flocs produced during flocculation was positively correlated with the amount of drug used, but the larger the flocs, the weaker the shear resistance, and the failure process of flocs was irreversible. Zeta potential indicated that PSS can effectively reduce its surface potential, which was the main mechanism of kaolinite flocculation in acidic system.

Key words: acid system, kaolinite, flocculation settlement, coagulant aid

摘要： 在处理含细泥、高硅有色金属矿物时，常出现沉降速率慢、固液分离难等问题，不利于后续的萃取-电积过程，从而影响生产的正常运转。为解决酸浸矿浆中除硅难的问题，本工作以-2000目(6.5 μm)高岭土为原料，探究了细粒高岭土在酸性体系下的絮凝沉降行为。结果表明，聚丙烯酰胺(PAM)对高岭土的絮凝性能强于聚乙二醇(PEO)。助凝剂聚苯乙烯磺酸钠(PSS)可以进一步提高絮凝效果，PAM和PEO与100 g/t PSS配合使用时絮凝作用最佳；而单宁酸(TA)的助凝效果不明显；利用聚焦光束反射测量(FBRM)发现，絮凝过程中产生絮团的大小与用药量呈正相关，但絮团越大，抗剪切能力越弱，且絮团的破坏过程是不可逆的；Zeta电位表明，PSS能够有效降低其表面电位，这是高岭土能够在酸性体系下絮凝的主要机理。

关键词: 酸性体系, 高岭土, 絮凝沉降, 助凝剂