Kivcet Flash Smelter

The Kivcet furnace requires complex piping for cooling water. At the top of the stairs is the area where lead bullion is tapped from the furnace to the Drossing Plant.

In addition to the thumbnail there is a larger schematic.

From the Handling Plant, concentrates and feed material pass to the Kivcet Flash Smelter. The Kivcet is a smelting furnace which produces lead bullion and slag.

The Kivcet Furnace is often described as a "flash" smelter because the sulphur in the dry lead concentrates and the fine coal burns instantaneously to form a 15% sulphur dioxide gas. Lead sulphide is converted to a lead oxide in this flash burn. A mixture of lead-zinc-iron oxides and flux agents form a semi-fused slag which collects under a layer of coarse coke called a "coke checker" in the first compartment of the furnace, called the smelting shaft. As this coke sinks through the slag, the lead oxide is reduced to lead bullion. This mixture of bullion and zinc-iron slag then passes under a separation wall from this first compartment to the second compartment where heat is applied by large carbon electrodes. With additional retention time, the lighter slag separates from the bullion to form two distinct layers of product. From this compartment, slag is tapped to the slag furnace and bullion is tapped to the Drossing Furnace.

About 1200ºC gas from the smelting shaft is cooled to 700ºC in the radiation boiler and further cooled in a convection boiler before passing through the gas cleaning equipment. The final volume of 22,000 m³/h cleaned sulphur dioxide gas is piped directly to the Sulphuric Acid Plants located in Zinc Operations.

There are a number of benefits associated with the new smelter and slag fuming plant. Compared to the old sintering and blast furnace operation shut down in 1997, the Kivcet smelter has reduced particulates (smoke) in the community by 90% and the metals emissions by 70% to 90%.

A more detailed explanation of the Kivcet flash smelter is also available.

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