During the reductive roasting of laterite ore with sodium sulfate as additive, sodium magnesium silicate and troilite are generated, this leads to high consumption of alkali and in turn environmental pollution of an alkali-rich tailing. Aiming to achieve the sustainable metallurgy by this route, oxygen pressure nitric acid leaching of laterite ore tailing was performed to recycle alkali and then heat storage material was prepared from the leached residue. The laterite ore tailing mainly consists of forsterite (Mg₂SiO₄), sodium magnesium silicate (Na₂Mg₂Si₂O₇), and troilite (FeS), of which 91.45% Na and 83.53% S were leached under the optimal conditions of leaching temperature of 150 °C and time of 60 min, HNO₃ concentration of 0.16 mol L⁻¹, and oxygen partial pressure of 0.50 MPa. The alkali can be reclaimed from the leachate after magnesium precipitation followed by evaporation and crystallization. A heat storage material with heat storage density of 243 kJ kg⁻¹ can be prepared from the leached residue. A route for the value-added utilization of this alkali-rich tailing was established.

Graphical Abstract

中文翻译：

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红土尾矿氧压酸浸：碱回收及蓄热材料制备

以硫酸钠为添加剂的红土矿石在还原焙烧过程中，会生成硅酸钠镁和硫橄榄石，导致碱消耗量大，进而导致富碱尾矿污染环境。为实现该路线的可持续冶金，对红土尾矿进行氧压硝酸浸出以回收碱，然后从浸出的残渣中制备蓄热材料。红土尾矿主要由镁橄榄石（Mg ₂ SiO ₄）、钠镁硅酸盐（Na ₂ Mg ₂ Si ₂ O ₇)和陨硫铁(FeS)，在浸出温度150 ℃、时间60 min、HNO ₃浓度0.16 mol L ^-1和氧分压的最佳条件下浸出91.45% Na和83.53% S 0.50 兆帕。浸出液中的碱可在镁沉淀后蒸发结晶后回收。浸出残渣可制备蓄热密度为243 kJ kg ^{-1的蓄热材料。}建立了该富碱尾矿的增值利用路线。

图形概要