两性聚丙烯酰胺乳液选矿剂的合成及絮凝作用

Synthesis and Flocculation of Amphoteric Polyacrylamide Emulsion Used as Mineral-dressing Agent

采用反相乳液聚合法合成了特性粘数最高可达26．7dL／g的两性聚丙烯酰胺乳液。扫描电子显微镜观测聚合后乳胶粒子尺寸为0．6—8μm；红外光谱测定证实了共聚物中AM、NaAA、DAC链节的存在。研究了阳／阴离子单体原料配比，聚合物特性粘数及其用量等对铝土矿赤泥絮凝性能的影响。这种速溶的两性聚丙烯酰胺乳液对铝土矿赤泥的絮凝效果显著：当APPAME质量分数为0．005％时，沉降时间仅需3min，沉淀区厚度〈40％，上层液透光率可达65％；其与泥浆粒子之间可通过电荷中和作用和吸附架桥作用的协同效应，而提高絮凝效果。

Amphoteric polyacrylamide emulsion, which has an intrinsic viscosity up to 26. 7 dL/g, was synthesized by inverse emulsion copolymerization, with latex particle size of 0. 6 - 8μm based on SEM. By means of FTIR measurement, it is demonstrated that the synthesized amphoteric polyacrylamide is composed of chain units of acrylamide （ AM ）, sodium acrylate （ NaAA ）, and acryloyloxyethyl trimethylammonium chloride （DAC）. The effects of DAC/NaAA feeding ratio, polymer intrinsic viscosity and dosage on the flocculability of bauxite red mud were studied. The amphoteric polyacrylamide emulsion is quickly dissolved in water, and the flocculating efficiency of it to the bauxite red mud is obvious. When the mass percent of the APPAME was 0. 005% , the precipitating time was only 3 min, with the deposited thinkness less than 40% , and the transmittance of fall-off liquid could reach 65%. Synergetic effect of electrostatic interaction and adsorption-bridging action between amphoteric polyacrylamide and slurry particles can further improve flocculating efficiency.