Development of a Sulfuric Acid Leach Process of Manganese Nodules at Moderate Temperatures

研究工作已在0.2 kg的台架试验上进行，并开发了一种新工艺，可将Ni富集为<Ni_3> <S_2>。结核（CM-17, 0.2 kg， -40 +60目，Cu 0.25, Ni 0.39, Co 0.33, Fe 11.7, Mn 18.5 wt%）在2N <H_2> <SO_4>的2L中浸出，373 K， 450rpm搅拌4hr。Cu、Ni、Co的浸出率分别为87.0、97.0、21.0%。这些数值高于烧杯量表测试的数值。浸出液中Cu、Ni和Co的浓度分别为0.22、0.35和0.07 g/L。在浸出液中逐渐加入钙质泥（Ca <CO_3> 93.6%），直至pH达到3.0,<Fe^(3+)>和<AL^(3+)>的去除率分别为98%和21%。将废铁（铁98.4%）加入到1L母液中，温度为363k。铜的回收率达99.5%，析出物中铜的含量为75%。以还原铁粉和<H_2> S为原料，在363 K条件下，以<Ni_3> <S_2>和CoS为混合硫化物回收Ni和Co的新工艺。最佳工艺条件为：358 ~ 368 K， 3[Fe]/[<Ni^(2+)>]摩尔比1.25,<H_2> S流量0.9L/[<Ni^(2+)> g/L]hr。Ni和Co在1 h的回收率分别达到99.5%和90%。

The research works have been performed on a bench-scale test of 0.2 kg and the development of a new process concentrating Ni as <Ni_3> <S_2> . Nodule(CM-17, 0.2 kg, -40 +60mesh, Cu 0.25, Ni 0.39, Co 0.33, Fe 11.7, Mn 18.5 wt%) was leached in a 2N <H_2> <SO_4> of 2L at 373 K for 4hr stirring at 450rpm. The percentages of leached Cu, Ni, and Co were 87.0, 97.0, and 21.0 %, resp. These valued were higher than those in the beaker-scale test. The Cu, Ni, and Co concentrations in the leach liquor were 0.22, 0.35,and 0.07 g/L, respectively. Calcareous mud (Ca <CO_3> 93.6%) was added gradually to the leach solution until the pH reached 3.0 and <Fe^(3+)> and <AL^(3+)> were removed 98 and 21 %, resp. without coprecipitation of Cu, Ni, and Co. Then, scrap iron(Fe 98.4 %) was added to 1L of the mother liguor at 363 K. The recovery of Cu reached 99.5 % and the Cu content in the precipitate was 75 %. A new process for the recovery of Ni and Co as a mixed sulfide of <Ni_3> <S_2> and CoS have been developed with reduced iron powder and <H_2> S at 363 K. The optimum conditions were as follows:358-368 K, 3[Fe]/[ <Ni^(2+)> ] molar ratio 1.25, and <H_2> S flow rate 0.9L/[ <Ni^(2+)> g/L]hr. The recoveries of Ni and Co reached 99.5 and 90 % at 1 hr, resp.