Feed the lead concentrate into a sintering machine. The sintering machine heats the material below its melting point, until the particles adhere to each other.
Transfer the material, along with carbon in the form of coke, to a blast furnace. A blast furnace will smelt the lead ore, removing oxides from it in order to leave the pure lead behind. A blast furnace continuously supplies the ore, coke and fuel through the top of the machine, so that chemical reactions can take place as the substance moves downwards. Hot blast air reacts with the coke to produce carbon monoxide and heat. The carbon monoxide, in turn, reduces the metal by removing oxides from the ore, leaving lead behind. The molten lead flows to the bottom of the furnace, forming four layers: speiss (arsenic and antimony), matte (copper sulfide and metal sulfides), blast furnace slag (silicates) and lead bullion, 98 percent by weight.
Drain off all the layers except for the lead bullion.
Agitate the lead bullion in a cast-iron kettle. Cool the lead to just above its freezing point, 370 to 425 degrees Celsius. A dross consisting of elements lighter than lead, such as arsenic, antimony and copper, will float to the top of the kettle. Skim off this dross.