METHOD OF LEAD IMPROVING Russian patent published in 1999 - IPC

FIELD: production of lead from low-grade raw materials. SUBSTANCE: method includes bath drip smelting of lead at temperature of 400-600 C in layer of preliminarily melted slag-forming material in the form of mixture of alkali and sodium fluoride, for instance, in ratio of 9:1 in the amount of 5-10% of lead weight. Bath drip smelting may be realized in standard electroslag refining furnace with use of black lead in the form of electrode immersed with it one end into melted layer of slag-forming material. The method ensures reduction of smelting time, high stable purity of produced lead, prevention of melt mixing, absence of vapor separation in working zone and no need of use of soda and reducing agent in the form of coke and similar substances, possibility of variation of slag bath sizes depending on chemical composition of black lead and possibility of rich lead ores with lead content exceeding 45%. EFFECT: higher efficiency. 1 tbl