Abstract Electric-arc furnace (EAF) slag is a waste generated in large quantities by the steelmaking industry. This waste contains high levels of Ca, Fe, Mn and Si. In the present study, an improved hydrometallurgical process was demonstrated for efficient recovery of Mn from EAF slag. Firstly, the EAF slag was dissolved in a mixture of nitric and hydrochloric acids to remove the insoluble Si-containing mixture. The generated leaching acid contained 6 g/L Mn, 26.9 g/L Ca, 15.9 g/L Fe and small amounts of other impurities. Secondly, Ca precipitated into anhydrite when concentrated sulphuric acid was added, and the residual Ca ion concentration was 213 mg/L. Thirdly, after Ca was precipitated, nearly 100% Fe was removed as hematite nanoparticles with 67.7% of Fe during the hydrometallurgical processes by adding methanol at an Mmethanol/Mnitrate ratio of 0.75, the retention rate of Mn was higher than 98.5%. Without adding methanol, only 54.8% of Fe was precipitated as an irregular hematite block. Fourthly, the residual Mn content is 5.8 g/L, which was recovered as hausmannite with Mn content of 60.3% when solution pH is adjusted to 8. Hydrolysis of Fe was not observed at 80 °C but accelerated when temperature was higher than 140 °C. Ethanol exhibited removal efficiency of Fe similar to that of methanol, but the optimal Methanol/Mnitrate molar ratio was 0.3, which was 2/5 that of methanol. By using the improved method, high-purity hausmannite product and hematite by-product were effectively recovered from the EAF slag without generating secondary waste.

中文翻译：

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从电弧炉渣中回收锰的湿法冶金工艺改进

摘要 电弧炉炉渣是炼钢工业产生的大量废弃物。这种废物含有高水平的钙、铁、锰和硅。在本研究中，证明了一种改进的湿法冶金工艺可以有效地从电弧炉渣中回收锰。首先，将电弧炉渣溶解在硝酸和盐酸的混合物中以除去不溶性的含硅混合物。生成的浸出酸含有6 g/L Mn、26.9 g/L Ca、15.9 g/L Fe和少量其他杂质。其次，加入浓硫酸后，Ca沉淀成硬石膏，残留Ca离子浓度为213mg/L。第三，在 Ca 沉淀后，几乎 100% 的 Fe 作为赤铁矿纳米颗粒被去除，67。在湿法冶金过程中通过添加甲醇以0.75的甲醇/硝酸盐比添加7%的Fe，Mn的保留率高于98.5%。不加甲醇，只有54.8%的Fe以不规则的赤铁矿块状沉淀。第四，残留的Mn含量为5.8 g/L，当溶液pH调至8时，回收为锰含量为60.3%的锰铁矿。在80°C下未观察到Fe水解，但在温度高于140°时加速C。乙醇对Fe的去除效率与甲醇相似，但最佳甲醇/硝酸盐摩尔比为0.3，是甲醇的2/5。采用改进后的方法，可以有效地从电弧炉渣中回收高纯度铁铝石产品和赤铁矿副产品，且不产生二次废物。Mn的保留率高于98.5%。不加甲醇，只有54.8%的Fe以不规则的赤铁矿块状沉淀。第四，残留的Mn含量为5.8 g/L，当溶液pH调至8时，回收为锰含量为60.3%的锰铁矿。在80°C下未观察到Fe水解，但在温度高于140°时加速C。乙醇对Fe的去除效率与甲醇相似，但最佳甲醇/硝酸盐摩尔比为0.3，是甲醇的2/5。采用改进后的方法，可以有效地从电弧炉渣中回收高纯度铁铝石产品和赤铁矿副产品，且不产生二次废物。Mn的保留率高于98.5%。不加甲醇，只有54.8%的Fe以不规则的赤铁矿块状沉淀。第四，残留的Mn含量为5.8 g/L，当溶液pH调至8时，回收为锰含量为60.3%的锰铁矿。在80°C下未观察到Fe水解，但在温度高于140°时加速C。乙醇对Fe的去除效率与甲醇相似，但最佳甲醇/硝酸盐摩尔比为0.3，是甲醇的2/5。采用改进后的方法，可以有效地从电弧炉渣中回收高纯度铁铝石产品和赤铁矿副产品，且不产生二次废物。当溶液 pH 值调至 8 时，回收为锰含量为 60.3% 的锰铁矿。在 80°C 时未观察到 Fe 的水解，但当温度高于 140°C 时会加速。乙醇对Fe的去除效率与甲醇相似，但最佳甲醇/硝酸盐摩尔比为0.3，是甲醇的2/5。采用改进后的方法，可以有效地从电弧炉渣中回收高纯度铁铝石产品和赤铁矿副产品，且不产生二次废物。当溶液 pH 值调至 8 时，回收为锰含量为 60.3% 的锰铁矿。在 80°C 时未观察到 Fe 的水解，但当温度高于 140°C 时会加速。乙醇对Fe的去除效率与甲醇相似，但最佳甲醇/硝酸盐摩尔比为0.3，是甲醇的2/5。采用改进后的方法，可以有效地从电弧炉渣中回收高纯度铁铝石产品和赤铁矿副产品，且不产生二次废物。是甲醇的 2/5。采用改进后的方法，可以有效地从电弧炉渣中回收高纯度铁铝石产品和赤铁矿副产品，且不产生二次废物。是甲醇的 2/5。采用改进后的方法，可以有效地从电弧炉渣中回收高纯度铁铝石产品和赤铁矿副产品，且不产生二次废物。