Research On The Composite Reforming Of Copper Slag And Silicomanganese Slag

The metallurgical slag discharged by enterprises in the production of copper,silicon-manganese alloy and other metal materials contains a large number of valuable elements,but the utilization level has been low for a long time.Piles of placed slag not only occupy land,pollute the environment,and waste resources,but also the latent heat of metallurgical slag has not been reasonably utilized.On the one hand,if the latent heat of the slag can be used up will greatly reduce the CO₂ emissions of the metallurgical industry;on the other hand,due to the physical and chemical properties of iron olivine in copper slag is very stable,so it is difficult to recover the iron element;on the other hand,silicomanganese slag contains a certain amount of free state CaO,MgO and MnO,the existence of free state CaO and MgO leads to its poor stability and difficult to be The presence of free CaO and MgO makes it difficult to be used in building materials due to its poor stability,while free MnO also inhibits the early hydration of cement.To address the current problems in the recycling and application of copper and silicomanganese slag,this paper proposes a composite modification process for hot molten slag and cold slag,in which the iron olivine in copper slag and（Ca,Mg,Mn）O in silicomanganese slag react to transform into the strongly magnetic spinel phase（Mn,Mg,Fe）Fe₂O₄ in a high-temperature oxidizing environment,while the remaining elements in the slag are solidly dissolved into the silicate phase.in the silicate phase.The spinel and silicate phases can be used as raw materials for the production of copper-containing antibacterial stainless steel and construction materials.In this way,the latent heat of the metallurgical slag is utilized,the valuable elements are recovered and the free CaO,MgO and MnO are stabilized.In this paper,the effect of the composite modification process on the mineral phase and microstructure morphology of the modified slag is studied,and the thermodynamic theory in the modification reaction is demonstrated,and the main experimental contents are summarized as follows:（1）The role of CaO,MnO and MgO in the modification process was explored by simulating the thermodynamic parameters such as dominance diagram,phase diagram,Gibbs free energy diagram and multivariate multi-phase equilibrium diagram during the modification reaction to optimize the chemical components of the slag,and the results showed that:the transformation of weakly magnetic iron olivine to strongly magnetic spinel was most efficient when 10%CaO was added on top of copper and silicomanganese slag in equal proportions,and the latter could be separated by the magnetic separation process;CaO could reduce the viscosity of the system,and MnO and MgO could promote the formation of spinel phase.The latter can be separated by magnetic separation process;CaO can reduce the viscosity of the system,MnO and MgO can promote the formation of spinel phase,however,when its content is too high,a large amount of silicate phase will be generated to turn and inhibit the spinel phase.（2）The effect of roasting conditions on the mineral phase type,grain morphology and size was investigated on the determined composition,and the effect of cooling mode on the mineral phase formation was explored.The results showed that:the heat treatment process of roasting at 1400℃ for 60 min and then cooling at a rate of1℃/min to 1150℃ with immediate air cooling was favorable to the growth of spinel and silicate phases,at which time the granular spinel was uniformly distributed in the silicate matrix phase;the glass phase produced by water cooling hindered the formation of spinel phase,furnace cooling had the hidden danger of excessive oxidation,and air cooling promoted the formation of spinel and silicate phases.（3）In view of the problem of low iron grade,the influence of different magnetic separation processes on the beneficiation effect was investigated,and the beneficiation effect before and after the modification was compared,and the results showed that:the iron recovery decreases with the decrease of particle size,while the iron grade gradually increases and approaches saturation;increasing the magnetic field strength is beneficial to improve the iron recovery but the iron grade is relatively low;the concentrate obtained at 74μm/325mT can be used for the production of copper containing Antibacterial stainless steel raw materials used,when the iron recovery and iron grade are 86%and 34%,respectively.In addition,the tailings can also be used as raw materials for the production of ceramic materials and microcrystalline glass for secondary use.