Study On Extraction Technology Of Valuable Metals In Laterite Nickel Ore

As the growing demand for the nickel and cobalt and dwindling of sulfide ore,reasonable exploitation and utilization of cobalt nickel laterite nickel ore extraction become the research focus.Nickel laterite is an important processes have attracted more and resource,and its metallurgical more attentions.Aimed at the shortages of traditional sulfation roasting process,such as high energy consumption and equipment corrosion,the method of ammonium sulfate roasting-water leaching was presented to explore the feasibility of low-temperature roasting ammonium sulfate.And the process that direct leaching the nickel laterite with hydrochloric acid-ammonium chloride solution system was presented to explore processing low content of nickel laterite ore chloride by wet process.The process of ammonium sulfate roasting water leaching laterite nickel ore was researched to study the factors of leaching rate,which includes ammonium sulfate dosage,roasting temperature,roasting time,leaching temperature,leaching time and solid-liquid.The results indicated that about 90.8%Ni,85.41%Co,86.74%Mn and 9.98%Fe,which achieves selective leaching of valuable metals.The thermodynamics of ammonium sulfate roasting was researched to analysis the effect of roasting temperature.The result shows that raising the temperature is beneficial to the reaction of serpentine ore and ammonium sulfate,and is not conducive the reaction of magnesioferrite and ammonium sulfate,which inhibits the sulfation of part of Fe.The XRD and SEM-EDS analysis of ammonium sulfate roasting products shows that the most of mineral phases are?NH₄?₃Fe?SO₄?₃,?NH4?2Mg2?SO₄?₃,Fe₂O₃,and SiO₂.Valuable metal exists in the form of sulfate,which leached into the aqueous phase.The iron mainly exists in the form of iron oxide that is water-insoluble.Through selective leaching of laterite nickel ore with ammonium chloride solution of valuable metals research,the results show that using ammonium chloride,leaching temperature is 100?,hydrochloric acid concentration is 2mol/L,solid-liquid ratio is 1:5,leaching time is 1.5 h.The result shows that the leaching rate of nickel is 89.45%,the leaching rate of cobalt is 88.56%,the leaching rate of manganese is 90.23%,and the leaching rate of iron is only 19.30%.The leaching mechanism of laterite nickel ore in chlorine salt solution is discussed by analysingthe XRD and SEM-EDS of leaching residue.The result shows that the aluminum salt solution is beneficial to dissolution of goethite in nickel laterite.The dynamic of the leaching process is researched to analysis the reaction process.The result shows that the leaching conforms with a new shrinking core model,in which both the interfacial transfer and diffusion through the product layer affect the reaction rate and the leaching activation energies of Ni,Co and Mn is 4.01 kJ/mol,3.43 kJ/mol and 1.87kJ/mol.The OLI systems software was used to simulation the hydrogen ion activity and the bubble of the solution of ammonium chloride-hydrochloric acid.The simulation results show that the ammonium chloride enhanced the hydrogen ion activity highly in hydrochloric acid solution and enhance the bubble of the solution.The hydrogen ion activity of hydrochloric acid-ammonium chloride solution with different concentrations was simulated.The result shows that when added 3 mol/L ammonium chloride to 2mol/L hydrochloric acid solution,the solution of hydrogen ion activity increased to 2.3 times,which get to 5mol/L hydrochloric acid hydrogen ion activity close.Increasing the bubble of the solution is beneficial to increase the temperature of the leaching reaction.The two different processes of leaching nickel laterite were presented in this paper.The process of ammonium sulfate roasting-flooding is an effective method for the treatment of nickel laterite and it is of significant importance to exploitation and utilization of low grade nickel laterite ore with high efficiency to extract nickel,cobalt and manganese closed circulation and good environment compatible.The process of hydrochloric acid-ammonium chloride solution system direct leaching nickel laterite can reduce energy consumption,and reduce the corrosion of the equipment which provide an idea of wet processing nickel laterite.The two processes have advantages and disadvantages,which is suitable for handing different nickel laterite ore and provides more selective process for the leaching of nickel laterite ore.