The traditional pyrometallurgical lead smelting process has many problems, such as serious environmental pollution, difficult recovery of sulfur in raw materials, high energy consumption and low production efficiency. Since the 1950s, some countries in the world have competed to study the direct lead smelting process to replace the traditional pyrometallurgical lead smelting process. By the 1990s, industrial production or semi-industrial tests have been carried out by KIVCET-CS, QSL, ISA and flash smelting. The common feature of these direct lead smelting methods is that they do not need to undergo separate sintering and roasting treatment, and basically realize self-heating smelting. The flue gas is easy to produce acid, and the degree of environmental pollution is light. From the perspective of development, it is possible to replace the traditional pyrometallurgical lead smelting method.

Lead is initially oxidized to PbO2 during heating and melting, and then decomposed to PbO after heating, and Pb3O4 (i.e. lead) is generated when heating to 603-723K. Pb2O3 or Pb3O4 is easy to dissociate at high temperature to form stable PbO.