| 摘要 |
A process for maintaining an aqueous suspension of solids (of particle diameter between 0.1 and 2000 microns) in liquid, comprises: adding to the water from about 0.1 to 100 p.p.m. of a hydrolysed polyacrylonitrile having a molecular weight of from 5000 to 40,000 and having from 20-30% amide groups and from 70-80% carboxyl groups based on the total of such groups, said polymer being further characterized by its substantial freedom from flocculating properties. The process can be applied to the treatment of power-station cooling water, paper mill white water containing TiO2 and pitch, scrubbing liquids used in steel mills. The dispersing agents can be used in conjunction with detergents. Other materials which can be dispersed are clays, quartz, iron oxides, calcite, kaolinite, organic matter, illite, and montmorillonite. In examples, polyacrylonitriles of molecular weights between 490,000 and 13,000 are prepared, and partially hydrolysed using NaOH. Tests for stability of suspension or flocculation are carried out on water suspensions Fe2O3 (1 p.p.m.) and kaolin (1 p.p.m. and 2 p.p.m.). The hydrolysed polyacrylonitriles used have molecular weights, amide group content and carboxylic acid group content of (3) 137,000, 25% and 75%; (4) 19,000, 30% and 70%; (5) 19,000, 23% and 77%; (6) 19,000, 17% and 83%; (7) 131,000, 30% and 70%; (8) 553,000, 30% and 70%; (9) 5 million, 20% and 80%. Results using acrylic acid monomer, acrylonitrile monomer, causticized lignin, causticized Mangrove tannin, sulphonated naphthalene sulphonate and carboxymethyl cellulose are given for comparison. |
