| 摘要 |
<p>PURPOSE:To obtain a red pigment from an industrial waste at a low cost, by decomposing a red soil slurry with a mineral acid. CONSTITUTION:A red soil slurry, a by-product produced in the extraction of aluminum oxide from bauxite, is adjust to PH <=4, preferably to PH<= 3-7.3, by adding a mimeral acid (preferably waste one), e.g., dilute sulfuric acid and it is decomposed, for example, by stirring for 1-5 minutes. The slurry is then meutralized with limestone, etc. and preferably classified to obtain finely divided particles with their diameters not more than 75mu, which are washed with water and dried to give the desired red pigment. EFFECT:Both a by-product and a mineral oil waste are used simultaneously effectively and pollution problems can be solved.</p> |
