两亲聚合物对湿法磷酸的助滤性能及机理研究

以实验室自制单体A、丙烯酰胺(AM)、二甲基二烯丙基氯化铵(DMDAAC)为原料,过硫酸盐氧化还原体系为引发剂,采用水溶液共聚法合成一种用于湿法磷酸助滤的两亲聚合物PADA-10。对所得聚合物的助滤性能进行研究,结果表明:磷酸料浆体系中加入PADA-10后,过滤速度提高了约4.3倍,滤饼水分降低了约10.8%。对PADA-10助滤机理的初步探究结果表明:PADA-10能在一定pH值范围内中和磷石膏表面电荷,使磷石膏微晶絮凝成团,添加PADA-10后滤饼的孔隙率增加;同时,PADA-10能增强磷石膏颗粒的疏水性,使磷酸滤液表面张力降低了5.2 mN/m,磷石膏表面接触角增大了3.4°。

Performance and mechanism of amphiphilic copolymer for filter aids on wet-process phosphoric acid

An amphiphilic copolymer PADA-10 which was applied to filtration aiding on wet-process phosphoric acid was synthesized with self-made monomer A,acrylamide(AM),dimethyl diallyl ammonium chloride(DMDAAC) as feedstock and with persulfate as initiator in aqueous solution.The filtration aiding effects of PADA-10 were studied,and the results show that the filtration rate of the phosphoric acid slurry can be increased by about 4.3 times and the water content of the filter cake can be reduced by about 10.8%,compared with the blank group.The filtration aiding mechanism of PADA-10 was preliminarily studied,and the results show that PADA-10 can neutralize the surface charge of the phosphogypsum within a certain pH range and can make the microcrystal grains flocculate to conglobation,moreover,PADA-10 can increase the porosity of filter cake.The results also indicate that PADA-10 can enhance the hydrophobicity of the phosphogypsum,the surface tension of the filtrate is reduced by 5.2 mN/m,and the surface contact angle of the phosphogypsum is increased by 3.4° with addition of PADA-10,respectively.