| Jinchuan nickel mine is China's famous polymetallic intergrowth oversize copper supplied ore,however,it mainly consists of low grade nickel ore and high content of basic gangue which leads many difficulties in flotation process.And it has high energy consumption,high emission of polluted and low recovery of valuable metals.In this paper,the ammonium sulfate with sodium sulfate is used as a roasting agent,and transformation behavior and transformation mechanism of metal elements in Jinchuan copper nickel sulfide ore were studied.The paper hopes that it can provide theoretical basis and technical supports to the economic development and comprehensive utilization of Jinchuan copper nickel sulfide ore.The copper-nickel sulfide ore belongs to high basic gangue sulfide ore which consists of Ni(4.63%),Cu(2.75%),TFe(32.23%),MgO(10.13%),which includes,pentlandite(Fe9Ni9S16),chalcopyrite(CuFeS2),lizardite(Mg3Si2O5(OH)4)magnetite(Fe3O4)and talc(Mg3(OH)2Si4O10).And nickel is mainly hosted in pentlandite and copper is mainly hosted in chalcopyrite.The thermomechanical analysis between mineral phases and ammonium sulfate showed that the reaction between the sulfides in the ore and ammonium sulfate is curred spontaneously ranging the temperature of 200?600?.The effect of roasting temperature,roasting time,particle size,mass ratio of ammonium sulfate/ore and the addition of sodium sulfate showed that the extraction of nickel and copper increased with the rise of roasting temperature and decreasing of particle size and increasing of mass ratio of ammonium sulfate/ore,and it firstly increased and then decreased with the extent of roasting time and addition of sodium sulfate.Orthogonal experiments were carried out to optimize the experimental conditions,the results showed that the optimal process conditions for extraction of Ni from copper nickel sulfide ore by ammonium sulfate roasting were powder particle size of 80?96?m,constant temperature time of 3 h,roasting temperature of 450 ?,anhydrous sodium sulfate addition of 4g(10 g ore),the ammonium ore ratio of 4:1,which extracted the more than 99%of nickel and 95%of copper.Second roasting was used to make a selective decomposition of sulfate.The result showed that it extracted 95.09%of nickel,80.43%of copper,14.96%of iron and 68.96%of magnesium at the condition of temperature of 680? and roasting time of 4 h.And the mechanism in second roasting process was studied,which showed that the decomposition pressure of ferric sulfate is higher than nickel sulfate,copper sulfate and magnesium sulfate,so we controlled the roasting temperature to realize the prior decomposition of ferric sulfate which made a controlled phase transformation.The dynamic of the calcination of ammonium sulfate in copper-nickel sulfide ores showed that the transformation processes of nickel,iron and magnesium are controlled by diffusion,the transformation process of copper is controlled by chemical reaction.The activation energy of each reaction is ENi=10.96kJ·mol-1,ECu=43.42kJ·mol-1,EFe=8.89kJ·mol-1,EMg=6.92kJ·mol-1.Dynamic equations are as follows:Ni 1+2(1-?)-3(1-?)2/3=1.40×10-2·exp(-10960/R7)t Cu 1-(1-?)1/3=2.07×10-2-exp(-43420/RT)t Fe 1+2(1-?)-3(1-?)2/3=7.4x10-3-exp(-8890/RT)t Mg 1+2(1-?)-3(1-?)2/3=1.04×10-3·exp(-6920/RT)t... |
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