Slag Activity Research And Numerical Simulation Of Heavy Metal Smelting Process With Short Flow

Short-flow clean smelting process is the development direction of heavy metal metallurgical technology. There have appeared some pilot programs of lead direct smelting and copper continuous smelting in the world in the past several decades, and some of them have already industrialized. But, no matter the smelting process or the metallurgical theory of the short-flow clean smelting, there are still many issues to be solve.In this paper, the slag activity research and the numerical simulation of the "lead flash smelting process" and "copper flash continuous smelting process", which have the independent intellectual property rights of china, were finished by the author. Those researches are helpful to explore the metallurgical law of those short-flow clean smelting processes, to perfect the theories of lead direct smelting and copper continuous smelting, to provide theoretical basis and practical guidance for the industrial applications of them, and also, to promote the development of those technologies. The specific research are shown as follows:According to the coexistence theory of slag structure, the activity calculation models for slag system of CaO-Cu2O-Fe2O3, Cu2O-CaO-SiO2-FeO-Fe2O3 and PbO-ZnO-CaO-SiO2-FeO-Fe2O3 were built. Then, the equal activity curves of CaO,Cu2O,Fe2O3,PbO and ZnO in those slag were drawed, and the influences of basicity and temperature on the activities NcaO,Ncu2O,NFe2O3 and the activity coefficientsγCu2o,γFeO,γPbO,γZnO were also analyzed. Results show that the calculated values are in good agreement with the reported measured values, showing that those models can wholly embody those slag structural characteristics. The research results supplemented the activity data of those new metallurgical slags, and proved the feasibility for the coexistence theory of slag structure to be applied to the field of non-ferrous metallurgy. Based on the principle of Gibbs free energy minimization, the thermodynamic model of the lead flash smelting process was built. Then, the multi-factor coupled simulation of the lead flash smelting process was carried out based on the model. By adjusting the Oxygen Volume Per Ton Concentrate (OVPTC), Oxygen Grade (OG), Temperature (T), flux quantity and concentrate composition, the integrated influences of those technology parameters on the sulfur content in bullion, the dust rate and the recovery rate of Pb were analyzed, and the change trends of equilibrium phase composition, oxygen potential and sulfur potential were studied, and the distribution behavior of Pb, Zn, Cu and Fe in each phase were also investigated. Results show that the thermodynamic model calculated values are in good agreement with the Outokumpu semi-industrial test values, and the model can wholly embody the lead flash smelting practice. It's a deliberate result for Outokumpu company, by taking into account the sulfur content in bullion, the dust rate, the recovery rate of Pb and so on, to carry out semi-industrial pilot, while OVPTC is 122 Nm3/t, OG is 95% and smelting temperature is 1210℃.The copper flash continuous smelting furnace can be regarded as a synthesis reactor of two relatively independent processes:Flash Matting Smelting Process (FMSP) and Copper Continuous Converting Process (CCCP). Based on this thinking, the multi-phase equilibrium model of FMSP and the local-equilibrium model of CCCP were built, and the integrated model of the copper flash continuous smelting process was made up by combinating the above two models with smelting intermediate materials. Then, the multi-factor coupled simulation of the copper flash continuous smelting process was carried out based on the integrated model. The influences of furnace structure, slag type and matte grade on blister formation thermodynamic condition were analyzed, and the change trends of equilibrium phase composition, oxygen potential and sulfur potential were studied, and the integrated influences of the technology parameters, including the Oxygen Volume Per Ton Concentrate (OVPTC), Oxygen Grade (OG), Temperature (T) and concentrate composition, on the sulfur content in blister, Fe3O4 behavior, copper content in slag, recovery rate of Cu, the behavior of Fe and matte were also investigated. Results show that the flash furnace, with double flues and slag partition wall, is an ideal reactor for copper flash continuous smelting, and the recovery rate of copper can be more than 97%.