Editing Lead (section)

==== Direct process ====
In this process, lead bullion and [[slag]] is obtained directly from lead concentrates. The lead sulfide concentrate is melted in a furnace and oxidized, forming lead monoxide. Carbon (as coke or [[coal gas]]{{efn|Gaseous by-product of the coking process, containing [[carbon monoxide]], hydrogen and [[methane]]; used as a fuel.}}) is added to the molten charge along with [[flux (metallurgy)|fluxing agents]]. The lead monoxide is thereby reduced to metallic lead, in the midst of a slag rich in lead monoxide.{{sfn|Davidson|Ryman|Sutherland|Milner|2014|p=17}}

If the input is rich in lead, as much as 80% of the original lead can be obtained as bullion; the remaining 20% forms a slag rich in lead monoxide. For a low-grade feed, all of the lead can be oxidized to a high-lead slag.{{sfn|Davidson|Ryman|Sutherland|Milner|2014|p=17}} Metallic lead is further obtained from the high-lead (25–40%) slags via submerged fuel combustion or injection, reduction assisted by an electric furnace, or a combination of both.{{sfn|Davidson|Ryman|Sutherland|Milner|2014|p=17}}