Two of the main challenges presented by the implementation of nickel laterites atmospheric acid leaching are: (i) high acid consumption and (ii) high final iron concentrations in the PLS. In the current work, a novel process was devised by applying pyrometallurgical and bio-hydrometallurgical operations. The experimental set-up comprised the reduction of a nickel limonitic ore with hydrogen gas in a rotary kiln, at 900 °C, until all the goethite was converted to metallic iron. Subsequently, the reduced sample was bioleached by mesophilic microorganisms grown on Fe²⁺ (Acidithiobacillus ferrooxidans) at 5% solids, 32 °C, and pH < 3. The results showed that an increase in the Eh values, promoted by the bacteria, resulted in the leaching Fe, Ni and Co, therefore a dissolution of 92% of the nickel and 35% of the cobalt was observed in experiments carried out with 35 Kg H₂SO₄/(ton of the reduced ore). The iron concentration in the liquor generated under these experimental conditions was below 5 mg/L owing to the fact that Fe³⁺ precipitated as jarosite. The experimental conditions applied also resulted in low acid consumption and the final total iron concentration was also reduced in the leach liquor (< 200 mg/L), which were considerably lower than the values reported for the HPAL process.

实施镍红土进行大气酸浸提所面临的两个主要挑战是：（i）高酸消耗和（ii）PLS中的最终铁浓度高。在当前的工作中，通过应用火法冶金和生物湿法冶金设计了一种新颖的工艺。实验装置包括在900°C的回转窑中用氢气还原镍铁矿，直至所有针铁矿都转化为金属铁。随后，还原的样品被在Fe ²⁺（酸性氧化硫杆菌）上生长的嗜温微生物生物浸出。）在5％的固体，32°C且pH <3的情况下。结果表明，细菌促进的Eh值增加，导致Fe，Ni和Co的浸出，因此溶解了92％的镍在35 Kg H ₂ SO ₄ /（还原矿石吨）进行的实验中观察到了35％的钴。在这些实验条件下产生的液体中的铁浓度低于5mg / L，这是由于Fe ³⁺沉淀为黄铁矿。所应用的实验条件还导致了较低的酸消耗，并且浸出液中的最终总铁浓度也有所降低（<200 mg / L），这大大低于HPAL工艺报告的值。