Research On Slag Physicochemical Properties And Copper Content Regulation Mechanism During Double Bottom-Blown Copper Smelting Process

The oxygen bottom blowing process is a new type of copper smelting method with independent intellectual property rights in my country.In recent years,it has been widely used in China,but there are technical problems of high copper content in slag and low direct yield of copper.Therefore,based on consulting a large number of related literature,the research on the physicochemical properties of slag in double-bottom smelting copper process and the regulation mechanism of copper content in the slag were carried out.The physicochemical properties of the chemical composition,mineral form and viscosity was clarified.And the process regulation mechanism for controlling copper content in smelting slag and converting slag was explored.The main research contents and results are as follows:（1）The chemical composition,mineral form,viscosity and other physicochemical properties in bottom blowing salg were researched by XRF,XRD,SEM,EDS and BPMA.The results showed that smelting slag and converting slag of bottom blowing are mainly composed of iron olivine,ferrite and other main phases.Copper mainly exists in the form of matte in the smelting slag.And it was wrapped by iron olivine,glass and ferrite phases.Copper mainly exists in the form of metallic copper in the converting slag.It is closely associated with calcium,iron and silicon phases and ferrite.Both types of slag have high viscosity,which is not conducive to the separation of slag and copper.（2）Taking double-bottom blowing smelting copper process smelting and converting process as the object,the mathematical model of the double-bottom blowing was established based on principles of mass balance,thermal balance,chemical balance by metallurgical calculation desk（MetCal）.The practice data verifies that the calculation model of the double bottom blowing smelting copper process can basically reflect the double bottom blowing production practice.（3）For the bottom blowing smelting process,excessively high ore oxygen content per ton is unfavorable to the copper content in the smelting slag,and the content of Fe₃O₄ increases significantly.The loss of copper in the form of Cu₂S and Cu₂O increases significantly.It should be controlled below 140 Nm³/t.The high ratio of iron to silicon has little effect on the copper content of smelting slag,but it is helpful to the reduction of smelting slag,which should be controlled at about 2.0.Too High melting temperature is detrimental to reducing copper content in the slag.Under the premise of ensuring good fluidity of the smelting slag,it is approprite to control it at 1473 K.（4）For the bottom blowing converting process,when the oxygen content per ton exceeds a certain value（160 Nm³/t under the conditions of this research）,copper is mainly chemically dissolved and lost in the converting slag in the form of Cu₂O.Properly increasing the ratio of iron to silicon is beneficial to reduction of bottom blowing converting slag,but the copper content in the slag will increase,and it is appropriate to control it at about 1.1.It has little effect on copper content of the converting slag as for the converting temperature,and has significant effect on reducing the content of Zn and Sb in the slag.Considering factors such as energy consumption,furnace life and viscosity,etc.it is advisable to control it at about 1573 K.The research results have certain theoretical value and guiding significance for controlling the copper content in the slag and promoting the sustainable development of the double-bottom blowing smelting copper industry technology.