| 摘要 |
<p>Carbon is settled from aqueous suspension by the addition of polyethylene oxide having a "reduced viscosity" of at least 1. Values of 1.3-39.1 are specified. pH values of 2.38-8.35 are specified. The carbon may be in the form of coal, charcoal, carbon black, or lamp black. The polymer may be present in an amount of 1-300 p.p.m., preferably 1-100 p.p.m., of the aqueous solution. 0.5-5% of an antioxidant based on the polymer may be present. Antioxidants specified are N:N-di-(2-hydroxypropyl) - N1:N1 - di - (2 - hydroxyethyl) -, N:N:N1 - tri - (2 - hydroxypropyl) - N1 - (2 - hydroxyethyl) -, and N:N:N1:N1 - tetra - (2 - hydroxypropyl)-ethylenediamine. Other materials which may be present are sodium acetate, potassium carbonate, calcium carbonate and chloride, strontium chloride, magnesium nitrate, ferric chloride, ferrous sulphate, aluminium sulphate, and shale.</p> |
