Study On Reaction Mechanism Of Sulfidation Roasting And Orientation Reconfiguration Of Ore Facies Of Low Grade Copper-nickel Sulfide Ore

With the gradual consumption of high grade ore resources,it is of great practical significance to accelerate the exploration of high efficiency processing technology of low grade minerals.In this paper,Jinchuan low-grade copper-nickel sulfide ore is used as raw material,adding sulfur,carbon powder and sodium carbonate,and adopting the step sulfidation roasting process,the Co,Cu and Ni in the ore with oxidation phase and silicate phase are transformed into sulfide phase.The feasibility of the vulcanization reaction was verified by thermodynamic calculation and the thermodynamic conditions for the stable existence of vulcanization phase were analyzed.The mineral composition and content of low-grade copper-nickel sulfide ore were studied by process mineralogy,and the occurrence states of Co,Cu and Ni in ore were analyzed.The influence of process conditions on the curing rate of Co,Cu and Ni was investigated,and the curing roasting kinetics model was established.The main research results are as follows:(1)The main metallic minerals in Jinchuan low-grade nickel-sulfide copper deposit include magnetite,nickel-pyrite,pyrite,quartzite,chalcopyrite,chromite,etc.The main non-metallic minerals are serpentine,chlorite,talc,enstatite,hornblende,olivine and so on.The metal sulfide minerals in raw ore have low dissociation degree and fine particle size,which are dispersed and distributed in the ore.The mineral symbiosis is complex,dissemination size of minerals is fine,sulfide minerals and gangue minerals are closely symbiosis to form multi-ore facies aggregation.Ni occurs mainly in the form of sulfide phase in nickelpyrite and quartzite,some cobalt exists in the form of isomorphic substitution in these two minerals,and there are similar Ni and Co in gangue minerals and magnetite.Cu occurs mainly in chalcopyrite and vallerite;(2)The sulfide phases of Co,Cu and Ni can exist stably in the range of0-1000 ℃,and the occurrence of Me S(Me=Co,Cu,Ni)is beneficial to the increase of sulfur partial pressure and reaction temperature.In the process of step sulfidation roasting,Ni O,Co O and Cu O react with carbon powder and sulfur preferentially to generate Me S(Me=Co,Cu,Ni).Sodium carbonate can react with the silicate of Co,Cu,Ni,destroy the silicate structure,generate the corresponding oxidation phase,and then through the vulcanization reaction,improve the sulfide rate of valuable metals;(3)The amount of sulfur,carbon powder,sodium carbonate,roasting temperature,roasting time,mineral particle size and other technological conditions can have a regular effect on the vulcanization rate of Co,Cu,Ni.Fe,Ni and Co form stable sulfide solid solution at high temperature during the step sulfidation roasting process,which is conducive to the enrichment of valuable metals.The apparent activation energies of Co,Cu and Cu are 22.99 k J/mol,8.69 k J/mol and 10.63 k J/mol,respectively.