Smelting ferrous materials
AssigneeIllawarra Technology Corporation Limited
InventorHoward K. Worner
Life of this patent
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Abstract
Finely divided ferruginous material is intimately mixed with finely divided carbonaceous material and agglomerated and formed into pellets typically of a few cubic centimeters volume to form a feedstock for a smelting operation. The carbonaceous material includes carbon in both high reactivity and low reactivity forms typically provided respectively by sewage sludge or other biosolids and by coke fines, kish graphite, natural graphite, lignite or brown coal. Smelting is conducted in a bath smelting furnace with the bath temperature of at least 1420.degree. C. and preferably 1500.degree. C. in a manner controlled to destroy any organic compounds present, to use carbon as a source of fuel, to carburise the iron to around 4% carbon or higher and to provide an off-gas which can be processed to collect any volatilized metal values.
Claims19
A method of smelting in a continuous process, comprising intimately mixing ferrous material in particulate form with a mixture of a high reactivity carbonaceous material and a low reactivity carbonaceous material in particulate form, and wherein the low reactivity carbonaceous material is at least 5% by weight of the mixture forming a pelletised feedstock from an agglomeration of the ferrous material, the pelletised feedstock tolerating as minor components non-ferrous metal values, and carbonaceous material, said carbonaceous material having at least 5% by weight low reactivity form carbon, supplying the feedstock to an electric arc bath smelting furnace, with counter flow of slag and metal configured to operate in a counterflow of slag and metal fashion, and operating the furnace to maintain an iron bath temperature of at least about 1420.degree. C. and to use the carbonaceous material to reduce iron compounds in the feedstock, to provide a source of fuel for maintaining the selected elevated temperature in the furnace and to carburise molten iron in the bath, and processing of gases from the reduction furnace to retrieve any metal values in the off-gas, the pelletized feedstock being supplied to the furnace in a controlled manner and the high reactivity form carbonaceous material in the pelletised feedstock being a sufficient proportion to maintain an iron bath temperature of at least about 1420.degree. C. and the proportion of low reactivity carbonaceous material in the pelletised feedstock being sufficient to carburise the iron.
A method of producing cast iron comprising the continuous process of taking particulate ferruginous materials, and carbonaceous materials formed into an intimate solid mixture in agglomerated form, the mixture having both a high reactivity carbonaceous material and a low reactivity carbonaceous material, and wherein the low reactivity carbonaceous material is at least 5% by weight of the mixture, the method tolerating as minor components non-ferrous metal values, and conducting an electric arc bath smelting operation in a furnace to produce cast iron, the method being characterised by (a) incorporating in the agglomerates carbonaceous material in suitable forms to provide a significant proportion of relatively low reactivity carbon to high reactivity carbon, the carbonaceous material being principally other than sewage sludge and the agglomerates including trace elements, contaminants, organic material, non-ferrous metallic components and (b) feeding the agglomerates into the furnace in a controlled manner whereby adequate carburising of the molten iron occurs from some of the carbonaceous material and other carbonaceous material burns as a fuel to maintain required high temperature processing conditions such that any organic compounds are destroyed and any other non-ferrous metal values are discharged through a flue and can be collected in a collection system.
Dependencies are inferred from the claim text.