摘要
采用强化焙烧-浸出法处理超低品位硅酸镍矿,考察了各影响因素对镍和镁浸出效果的影响,获得了最佳工艺条件,并通过X射线衍射(XRD)、傅立叶变换红外吸收光谱仪(FTIR)及扫描电镜(SEM)等方法揭示了氟化钙提高镍、镁浸出率的机制,结果表明:在焙烧温度为1100℃,焙烧时间为60 min,氟化钙用量为10%,浸出终点p H为1.5,浸出温度为50℃,浸出时间为5 h的条件下,镍浸出率可达74.9%,镁浸出率可达84.3%;氟化钙提高镍和镁浸出率的机制在于:在焙烧过程中氟化钙解离出的氟离子取代O2-进入矿物晶格中,造成矿物中稳定的桥氧键断裂,使得硅氧四面体坍塌,强化了对矿物晶体结构的破坏,进一步释放镍和镁;此外,在浸出过程中氟离子与镍离子、镁离子易形成溶于酸的六氟化镍配合物和氟镁络合物,增加镍、镁离子在浸出液中的稳定性,且氟离子更容易渗透到硅酸盐结构内部,降低氢离子迁移造成的电势差,促进氢离子在硅酸盐内部扩散,强化氢离子对硅酸盐中镍和镁的置换脱附作用,同时氟离子在酸性条件下能够腐蚀硅酸盐矿物,释放矿物中吸附的镍、镁离子,在综合作用下,提高了镍和镁的浸出率。
Nickel as an important strategic metal,is widely used in military manufacturing and new energy fields,due to the rapid development of new energy,the price of nickel is gradually rising,and the competition for nickel resources is becoming increasingly fierce.With the depletion of easily processed and highly valuable nickel ore resources,difficult to treat nickel ore resources,especially nickel silicate ore resources,are gradually receiving attention.Nickel silicate ore is a relatively difficult to treat nickel ore,especially low-grade nickel silicate ore,the current methods for treating nickel silicate mainly include nickel matte smelting,nickel iron smelting,reduction roasting ammonia leaching method,chlorination separation roasting magnetic separation method,high-pressure acid leaching method,etc.The first two methods mentioned above are suitable for treating nickel ores with high nickel iron content,while the reduction roasting ammonia leaching method and chlorination separation roasting magnetic separation method are suitable for treating nickel ores with a nickel grade of about 1%.Although the high-pressure acid leaching method has a high nickel recovery rate,but it is mainly suitable for nickel oxide ores with low silicon and magnesium content,and there are problems such as high investment costs and equipment corrosion.At present,the nickel in the tailings of many nickel beneficiation plants is mainly nickel silicate,which is difficult to separate and can only be stacked in tailings ponds,causing waste of nickel resources,if the nickel silicate in the tailings of nickel beneficiation plants can be utilized,it will create significant economic benefits.In order to extract nickel from nickel silicate,an efficient method had been developed,the ultra-low grade nickel silicate ore was treated by using enhanced roasting leaching method in this paper.The influence of various factors on the leaching effect of nickel and magnesium was investigated,and the optimal process conditions were obtained.The mechanism of calcium fluoride improving the leaching rate of nickel and magnesium was revealed through X-ray diffraction(XRD),Fourier transform infrared spectrometer(FTIR)and scanning electron microscope(SEM).The results showed that,under the conditions of roasting temperature of 1100℃,roasting time of 60 min,calcium fluoride dosage of 10%,leaching end point pH of 1.5,leaching temperature of 50℃,leaching time of 5 h,nickel leaching rate could reach 74.9%,magnesium leaching rate could reach 84.3%,the use of enhanced roasting leaching method could effectively extract nickel and magnesium from ores.It could be found from the experiment that the roasting of calcium fluoride could improve the leaching rate of nickel and magnesium in the roasting stage and leaching stage.The mechanism of calcium fluoride improving the leaching rate of nickel and magnesium was as follows:during the roasting process,fluoride ions dissociated from calcium fluoride replace O^(2-)and entered the mineral lattice,causing the stable bridging oxygen bonds in the mineral to break,causing the collapse of silica tetrahedra,strengthening the destruction of mineral crystal structure,and further releasing nickel and magnesium.In addition,in the leaching process,fluoride ion,nickel ion and magnesium ion were easy to form acid soluble nickel fluoride complexes and magnesium fluoride complexes,and increasing the stability of nickel and magnesium ions in the leaching solution.Moreover,fluoride ions were more likely to penetrate into the interior of the silicate structure,reducing the potential difference caused by hydrogen ion migration,promoting the diffusion of hydrogen ions within the silicate,and strengthening the displacement and desorption effect of hydrogen ions on nickel and magnesium in the silicate.At the same time,fluoride ion could corrode silicate mineral under acidic conditions,release nickel and magnesium ions adsorbed in minerals,and improve the leaching rate of nickel and magnesium under the combined action.The study explored the treatment of low grade by enhanced roasting leaching method from the perspectives of experimental results and mechanism,and it also provided a theoretical basis.Enhanced roasting leaching method could serve as a technical reserve,and as nickel prices gradually rose,the applicability of this method gradually became apparent.This study could provide certain reference and reference for the treatment of nickel silicate ore,and had important reference significance for nickel extraction in complex nickel ores,at the same time,it could also promote the development of nickel resource comprehensive utilization technology.
作者
文堪
王朝
李耀山
刘远
解万文
王铧泰
Wen Kan;Wang Zhao;Li Yaoshan;Liu Yuan;Xie Wanwen;Wang Huatai(Western Mining Group Technology Development Co.,Ltd.,Xining 810006,China;Qinghai Provincial Key Laboratory of Plateau Mineral Processing Engineering and Comprehensive Utilization,Xining 810006,China;Qinghai Nonferrous Mineral Resources Engineering Technology Research Center,Xining 810006,China)
出处
《稀有金属》
CSCD
北大核心
2024年第12期1815-1822,共8页
Chinese Journal of Rare Metals
基金
青海省创新平台建设专项(2022-ZJ-Y09)资助。
关键词
强化焙烧
硅酸镍
酸浸
镍回收
氟化钙
enhanced roasting
nickel silicate
acid leaching
nickel recovery
calcium fluoride
作者简介
文堪(1993.12-),男,陕西商洛人,硕士研究生,工程师,研究方向:稀贵金属综合回收,E-mail:m18710482285@163.com;通信作者:刘远,高级工程师,电话:15308485186,E-mail:444151102@qq.com。
