水酸化鉄と石膏の浮選分離におよぼす有機抑制剤の効果

抄録

Acid drainage from iron sulfide mine is neutralized with calcium carbonate or calcium hydroxide errous ions to ferric ions. The precipitates formed, which mainly consist of ferric hydroxide and gypsu, mafter the oxidation off ailing dam. It is important to utilize these precipitates as iron and gypsum resources, are dumped to millt. Thus, the separation of ferric hydroxide from gypsum by flotation method has been investigated. It was shown that synthetic acid mine water containing 1000mg/l of ferric ions and 6000mg/l of sulfate ions was neutralized with calcium carbonate, and gypsum thus formed was selectively recovered in the froth using dodecylammonium acetate as a collector and soluble starch as a depressant for ferric hydroxide. It was also shown that soluble starch acted as a selective flocculant as well as a depressant for ferric hydroxide.
In the present paper, in order to find some effective organic depressants other than soluble starch for the flotation senara. tion of ferric hydroxide from gypsum, flotation tests were made at the same condition as above mentioned. And the effects of Several organic depressants such as tannin, gelatin, Na-carboxymethyl-cellose (C. M. C.) and soluble starch on the separation of ferric hydroxide from gypsum were investigated. As a result, soluble starch was found to be the most effective depressant tested, followed by gelatin, for ferric hydroxide. These two depressants markedly improved the selectivit. But tannin and C. M. C. were not so ettective.
Then, sedimentation tests were conducted for the suspension of ferric hydroxide and gypsum respectively, and the effects of above reagents used as depressant on the flocculation of the suspension were investigated. It was shown that each reagent did not flocculate gypsum but strongly flocculated ferric hydroxide and this result was thought to have some effects on flotation for separating these precipitates.
Also, flotation tests were made on the separation of ferric hydroxide from gypsum using some starches and starch products such as soluble starch, corn starch, potato starch and dextrin. It was found that soluble starch gave the best selectivity tested, followed by dextrin, potato starch and corn starch in the order named.