Study On The Enrichment Of Ferronickel From Silicon-magnesium-type Poor Nickel Laterite Ore And The Recovery Of Magnesium From Tailings

There are two main types of nickel resources available for development worldwide:nickel sulfide ore and nickel oxide ore.Due to the increase in demand for nickel,the resources of high-grade and easy-to-handle nickel sulfide mines have decreased,and low-grade laterite mines have become the focus of research.A laterite mine in Yunnan,China has the characteristics of high MgO,high SiO ₂,and low nickel-iron content.It is a typical low-grade silicon-magnesia laterite nickel ore.Scholars at home and abroad have conducted extensive research on nickel recovery,Magnesium,as a metal with high value,currently has the disadvantages of high cost and low recovery rate for the direct extraction of magnesium from laterite ore.This paper proposes a reduction roasting-magnetic separation-sulfuric acid leaching experimental method to comprehensively recover the silicon-magnesium type laterite nickel ore Valuable metals nickel,iron,magnesium and other substances.First,the laterite mineral component contains Ni 0.82%,Co 0.033%,Fe9.67%,MgO 31.49%,and SiO₂ 35.85%.Adding 7% flux CaF₂ and 8%reducing agent anthracite to the laterite ore,under the protective atmosphere of nitrogen,the effect of four different roasting temperatures on the recovery rate of ferron ickel was investigated.The comprehensive experimental process selected roasting at 1250? for 60 min After that,wetting and magnetic separation are used to obtain nickel-iron concentrate and magnetic separation tailings.After the enrichment of laterite ore,the grade of nickel in the nickel-iron concentrate reaches 6.60%,and the grade of iron increases to 62.14%.Among them,8.65% of magnesium oxide is not completely separated.The SEM and EPMA detection and analysis of the raw ore,roasted materials and magnetic separation tailings were carried out.High temperature roasting resulted in an enrichment process of reduction,migration,aggregation and growth of nickel-iron metal.The change process at high temperature was analyzed specifically.Secondly,magnetic separation tailings were used as raw materials for magnesium extraction by subsequent sulfuric acid leaching.The effects of different leaching conditions on the leaching rate of magnesium,iron and nickel were investigated.Single factor experiments and repeated experiments were carried out to obtain the best acid leaching conditions:Leaching temperature 80?,leaching time 4h,sulfuric acid concentration 15%,liquid-solid ratio 10:1?in m L/g?,stirring speed:450 r/min.And under this condition,three sets of repeatability tests were carried out,and the leaching rates of Mg,Ni and Fe reached 96.69%,98.63% and 62.8%respectively.In order to obtain pure magnesium oxide products,a neutralization hydrolysis iron removal experiment was carried out,because the iron in laterite is ferric iron,it is not suitable to remove iron using goethite method,and it is not suitable to introduce new Na⁺,K⁺ and other impurity ions Therefore,the iron-aluminum method is not applicable.The iron content in the liquid after iron removal is only 5.38mg/L.By adding ammonia water NH₄·OH to the liquid after iron removal to adjust the pH to 9.6?9.7,ammonium carbonate?NH₄?₂CO₃ was added to it several times.After two steps of metathesis and pyrolysis,basic magnesium carbonate was obtained.It was dried in a 105? drying oven for 6 hours to obtain white powder of basic magnesium carbonate.Finally,the product magnesium oxide is prepared.The basic magnesium carbonate is ground in a T1700-LB vertical injection furnace for high temperature calcination,and the temperature is calcined at 550? for 1h.The grade of the obtained magnesium oxide reaches 98% and is higher than 96.0%,reaching the national standard GB 1886.216-2016 The standard content of food grade magnesium oxide.