| 摘要 |
<p>PURPOSE:To recover sulfuric acid having high concn. and low Ni content by adding a specified amount of seed crystals of CaSO4.2H2O to a copper-freed electrolytic soln. contg. a specified amount of sulfuric acid, allowing the soln. to stand at a specified temp. or below for a specified time or more, filtering it, and diffusing and dialyzing the filtrate with an ion exchange membrane. CONSTITUTION:To a copper-freed electrolytic soln. having >=300 g/l free sulfuric acid after the electrolytic refining of copper are added 0.2-10 g/l seed crystals of CaSO4.2H2O, and the soln. is allowed to stand at <=25 deg.C for >=2 hr to precipitate Ca as gypsum. The soln. is then filtered, and the filtrate is fed to a diffusion dialytic vessel provided with an ion exchange membrane to carry out diffusion dialysis. Thus, sulfric acid having low Ni concn. and high purity and a dialyzed soln. having high Ni concn. are obtd. The resulting sulfuric acid is repeatedly utilized in an electrolytic cell.</p> |
