The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 02, 1985
Filed:
Apr. 30, 1984
Johan S Leirnes, Skelleftehamn, SE;
Malkolm S Lundstrom, Skelleftea, SE;
Martin L Hedlund, Ursviken, SE;
Kurt J Buren, Skelleftehamn, SE;
Boliden Aktiebolag, Stockholm, SE;
Abstract
The invention relates to a method for producing lead having a sulphur content beneath about 2%, from sulphur-containing oxidic lead raw materials contaminated with zinc and/or other readily oxidized elements, by smelting the materials in a furnace in which the furnace contents can be agitated. When practicing the method, the lead raw materials are charged to the furnace together with iron-containing fluxes and solid reduction agents. The charged materials are heated under agitation, to form a lead phase and a slag phase. The amount of reduction agent charged is selected so that at least all the lead contained in the furnace is reduced to lead metal and the amount and composition of the fluxes are selected so that a terminal slag is obtained in which the sum of the iron and zinc present is 30-40%, and so that the slag has a content of 15-25% of both SiO.sub.2 and CaO+MgO. Lead raw materials, fluxes and reduction agents are suitably introduced in a plurality of charges, with intermediate moderate heating, prior to commencing the smelting process.