Study On The Energy Analysis Of The Suspended Lead Smelting Process And The Measurement Method Of Slag Oxygen Potential

The suspended lead smelting technology with the feature of strong raw material adaptability and less pollutant emission is a kind of direct lead smelting technology. A domestic enterprise have introduced the technology and developed the technology to deal with the dip zinc slag, what’s more, technical personnel have devoted themselves to exploring the operation and control of the technology. In this paper the test and calculation for the thermal balance of suspended lead smelting system was launched and the composition and morphology of the slag sample were detected and analyzed by various detection methods. Based on the test results, the component activity model of smelting slag was built combining the mathematics with computer technology. The theory oxygen potential was achieved by the lead oxide activity obtained by the component activity model. Finally the oxygen potential of smelting slag in production conditions was tested and analyzed using rapid oxygen measurement, and the results were compared with the theory oxygen potential. The main conclusions are summarized as follows:1) The main components of the lead smelting slag are element lead, zinc silicate, franklinite, ferrous oxide and zinc calcium silicate; The produced zinc iron spinel increases the viscosity of the smelting slag which makes the elemental lead whose diameter below40μm hard to flow, thus making the convergence and settlement of lead difficult to proceed, therefore the lead is entrapped in the slag. All mentioned above is the main reason of the lead loss in the smelting slag.2)The thermal efficiency of the suspended lead smelting system is74.72%and carbon unit consumption is42(kg/t crude lead), which are close to the design value; Cooling water take away31.1%of the thermal energy, slag take away15%of the calories.3)The activities obtained from the five element (PbO-ZnO-CaO-SiO2-FeO) slag system model accord well with the measured data,which can accurately reflects the slag nature. According to the slag composition, the activity of PbO in five element slag system is calculated to be0.0025,then the theory oxygen potential is reckoned to be-10.5from the Equilibrium diagram for Pb-Fe-O.4)The oxygen sensor eqquiped with oxygen concentration cell can be used for the measurement of oxygen potential in smelting slag, the range of the oxygen potential logarithm is from-11.37to-10.32, in other words the oxygen pressure is from10-6.37to10-5.32Pa, which is in accordance with the theory oxygen potential; the response time of the potential and temperature signals are from10s to15s, and the measuring time can be controlled within15s-25s.