Currently, with the increasing demand of nickel and cobalt, more and more attention has been placed on hydrometallurgical processing to treat laterite ore. The nitric acid pressure leaching (NAPL) has several advantages. In order to solve the problems of environmental pollution and resource wastage caused by the NAPL residue, this work proposes a novel and green process for treating laterite residue to prepare high-purity iron phosphate. The laterite residue was subjected to selective leaching by 6.0 mol L⁻¹ phosphoric acid. The pregnant leach solution (PLS) was used to prepare iron phosphate by induced precipitation. The selective leaching was conducted using 6.0 mol L⁻¹ H₃PO₄ of to obtain high extraction of iron. After leaching and clarification of PLS iron phosphate was precipitated in two steps by controlling temperature and pH, to yield more than 94% iron phosphate. The reaction mechanism of the induced precipitation was analyzed, which illustrated that intermediate products were first formed from the leach liquor and then transformed to FePO_4(s). Characterization of the iron phosphate showed that the product displayed flowerlike morphology with high purity and dispersion. This process not only solves the serious environmental damage by accumulation and landfill of laterite residue, but also improve the efficiency of resource utilization for the hydrometallurgical nickel laterite industry.

目前，随着对镍和钴的需求不断增加，湿法冶金加工处理红土矿石越来越受到重视。硝酸加压浸出 (NAPL) 具有几个优点。为解决NAPL渣造成的环境污染和资源浪费问题，本工作提出了一种新型绿色处理红土渣制备高纯磷酸铁的工艺。红土残渣用6.0 mol L ^-1磷酸进行选择性浸出。富浸出液 (PLS) 用于通过诱导沉淀制备磷酸铁。使用6.0 mol L ^-1 H ₃ PO _{4进行选择性浸出}以获得高提取率的铁。PLS经浸出澄清后，通过控制温度和pH，分两步沉淀出磷酸铁，得到94%以上的磷酸铁。分析了诱导沉淀的反应机理，表明中间产物首先由浸出液形成，然后转化为FePO _4(s)。对磷酸铁的表征表明，产物呈现出高纯度和分散性的花状形态。该工艺不仅解决了红土渣堆积填埋对环境造成的严重破坏，而且提高了湿法冶金镍红土工业的资源利用效率。