ABSTRACT

The present study investigated a novel method of alkaline ferricyanide leaching to extract palladium (Pd) from a Western Australian disseminated platinum-group metal (PGM) oxide ore that bears Ni and Cu. While cyanide has been used to leach Pd, it is well known for its toxicity and large consumption in the presence of base metals. A more benign alternative, in the form of alkaline ferricyanide, is evaluated in this research to serve the combined role of lixiviant and oxidant. Various leaching parameters, such as ferricyanide concentration (1–30 g/L), dissolved oxygen level (up to 25 ppm), pH (10–12), and temperature (20–80°C), were investigated to evaluate Pd extraction. The Pd extraction was found to be the most sensitive to leach temperature with Pd extraction doubling when the temperature was raised from 20°C to 80°C. The highest Pd extraction of 76.1% was achieved at 10 g/L ferricyanide, pH 11, DO 15 ppm, 80°C, and 10% solids. The alkaline ferricyanide leaching system showed high selectivity for Pd over other metals (Pt, Co, Ni, Cu). The co-extractions of base metals (Co, Cu, and Ni) were all below 2%, and that of Pt was below 10% over the range of temperatures investigated. Although conventional cyanidation at a low cyanide consumption (1 kg/t) showed slightly better performance in Pd extraction, the ferricyanide leaching significantly improved the settleability and filterability of the leaching slurry considering the finely ground nature and high-clay content of the lateritic oxide ores. In contrast, the cyanidation leaching slurry was found to filter or settle poorly.

摘要

本研究研究了一种从西澳大利亚含镍和铜的浸染型铂族金属 (PGM) 氧化物矿石中提取钯 (Pd) 的碱性铁氰化物浸出的新方法。虽然氰化物已被用来浸出钯，但众所周知，氰化物具有毒性并且在贱金属存在下消耗量很大。本研究评估了一种更良性的替代品，即碱性铁氰化物，以发挥浸滤剂和氧化剂的综合作用。研究了各种浸出参数，如铁氰化物浓度 (1–30 g/L)、溶解氧水平（高达 25 ppm）、pH (10–12) 和温度 (20–80°C)，以评估 Pd 萃取。发现 Pd 提取对浸出温度最敏感，当温度从 20°C 升至 80°C 时，Pd 提取量加倍。在铁氰化物浓度为 10 g/L、pH 11、DO 15 ppm、80°C 和固体含量 10% 时，Pd 萃取率最高为 76.1%。碱性铁氰化物浸出系统对 Pd 的选择性高于其他金属（Pt、Co、Ni、Cu）。在研究的温度范围内，贱金属（Co、Cu 和 Ni）的共萃取率均低于 2%，Pt 的共萃取率低于 10%。尽管低氰化物消耗（1 kg/t）的常规氰化法在钯提取方面表现出稍好的性能，但考虑到红土氧化矿石的细磨性质和高粘土含量，铁氰化物浸出显着改善了浸出浆的沉降性和过滤性。相反，氰化浸出浆液的过滤或沉降效果较差。碱性铁氰化物浸出系统对 Pd 的选择性高于其他金属（Pt、Co、Ni、Cu）。在研究的温度范围内，贱金属（Co、Cu 和 Ni）的共萃取率均低于 2%，Pt 的共萃取率低于 10%。尽管低氰化物消耗（1 kg/t）的常规氰化法在钯提取方面表现出稍好的性能，但考虑到红土氧化矿石的细磨性质和高粘土含量，铁氰化物浸出显着改善了浸出浆的沉降性和过滤性。相反，氰化浸出浆液的过滤或沉降效果较差。碱性铁氰化物浸出系统对 Pd 的选择性高于其他金属（Pt、Co、Ni、Cu）。在研究的温度范围内，贱金属（Co、Cu 和 Ni）的共萃取率均低于 2%，Pt 的共萃取率低于 10%。尽管低氰化物消耗（1 kg/t）的常规氰化法在钯提取方面表现出稍好的性能，但考虑到红土氧化矿石的细磨性质和高粘土含量，铁氰化物浸出显着改善了浸出浆的沉降性和过滤性。相反，氰化浸出浆液的过滤或沉降效果较差。在研究的温度范围内，Pt 的含量低于 10%。尽管低氰化物消耗（1 kg/t）的常规氰化法在钯提取方面表现出稍好的性能，但考虑到红土氧化矿石的细磨性质和高粘土含量，铁氰化物浸出显着改善了浸出浆的沉降性和过滤性。相反，氰化浸出浆液的过滤或沉降效果较差。在研究的温度范围内，Pt 的含量低于 10%。尽管低氰化物消耗（1 kg/t）的常规氰化法在钯提取方面表现出稍好的性能，但考虑到红土氧化矿石的细磨性质和高粘土含量，铁氰化物浸出显着改善了浸出浆的沉降性和过滤性。相反，氰化浸出浆液的过滤或沉降效果较差。