Show 6 The Story of Milling and Smelting at Midvale O 7 c M J v Ty jf L 1 J i ii II I r i r I y r 49 42 s Not unlike huge soup bowls the lead kettles at Midvale Utah plant represent one of the last steps In Inthe inthe d the production of lead bullion The soup fed Into these huge kettles is molten lead and here Impurities imd Im im- are removed before the lead Is Es cast into anodes i Editors Editor's Note This Is the thc fourth of a series of five fhe articles article on the story of milling milling millins mill mill- ing ins and smelting of lead zinc lead zinc ore at Mid Midvale The previous ious article of oC this series described briefly flotation notation of lead lead- zinc ores At its Midvale ale Plant United States Smelting Refining and Mining Mining Min Min- ing company annually treats thousands thousands thou thou- sands of or tons of lead zinc lead zinc milling ores in its modern fully equipped custom flotation mill and additional thousands of at tons of at siliceous and of- of direct smelting smelling ores In lu its large smelter smeller A substantial portion of this tonnage tonnage- comes from numerous Independent mining Companies In ing g Arizona California Colorado jis Idaho Montana Oregon and other outside points Yes Midvale is an nn important spot on the milling and smelting map of or the tho world The smelter situated adjacent to the flotation mill discussed In previous article treats concentrates concen from iron the mill and direct smelting ores from company and custom mines In Utah and out out out-of- of state points After Arter weighing and sampling these materials are placed Into bins to be withdrawn later for roasting or sintering Weighed amounts of certain concentrates ores roaster calcines other materials and fluxes are sintered In order to combine the fine materials into a sinter cake This sinter cake together with oxidized lead ores limo rock scrap Iron and furnace coke make makeup up a charge for the blast furnace The entire charge chargo is b by bythe bythe the intense heat of the furnace The lead trickles through the charge to the bottom of ot the furnace collecting the gold and and silver and some of the other metals The molten lead Is drawn oft off Into Immense immense immense im Im- mense kettles where somo some of the Impurities are eliminated before the lead bullion slabs are cast for shipment shipment shipment ship ship- ment to the lead refinery In the refinery the lead bullion Is refined producing a R high grade lend lead and certain byproducts byproducts by hy products also gold and silver er This electrolytic refining rennin Is similar to the well known electroplating pro pro- process cess THE FIFTH OF THESE ARTICLES WILL APPEAR SOON I I J I |