Flocculation and sedimentation behavior of kaolinite in acidic systems
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.
acid systemkaoliniteflocculation settlementcoagulant aid
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