UA106267C2 - METHOD for lead refining - Google Patents

Abstract

The invention relates to non-ferrous metallurgy, in particular to a method for lead refining. According to the method molten decoppered lead is refined in two stages, at the first stage the melt is bubbled with oxygen while stirring with a blade paddle mixer at the rotation speed of about 350-400 r./min until the required lead cleanliness from impurities of antimony, arsenic, tin, and simultaneously, to an average value of tensile strength of lead sample s equal to 13-20 N/mm, in the second stage the melt is mixed with molten alkali, which is added in a volume of 3.5- per tonne of lead, which is refined during the time according to the formula: t=(0,57⋅s- 6,4)±0,2, where s – is the average value of tensile strength of the lead sample, N/mm, t - is duration of refining, hours. At that the consumption of oxygen by bubbling is 10-20 l/min per 100 tonnes of the molten lead, lead decoppering before refining thereof from impurities of antimony, arsenic, tin is carried out in two stages, at the first stage lead decoppering is carried out by eliquation - cooling of the black lead from 800- to 600- and removing the dry slurries, re-cooling to 350- and removing fatty slurries, in the second stage with fine decoppering of black lead is carried out with the mixture of sulfur powder S with pentlandite (nickel-iron pyrite) with the pentlandite content of 3 -6 wt. %, and the rest is sulfur which is stirred into the molten lead with a mixer in an amount of 0.9- per 1 ton of the black lead at a temperature of 420-. The invention provides increasing of a lead refining efficiency, reducing the content of impurities therein.