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The European stainless steel producers generate 20 -30 kg dust per ton of produced stainless steel.The dust formed during various stages of the production process contains valuable metals such as Cr,Ni and Mo.In general this dust is considered as a hazardous waste.If not taken care of the dust will be an environmental risk causing potential problems such as leaching of heavy metals into groundwater and pollution of land and air.By applying techniques for recycling the dust the problem is minimized and valuable metals are recovered and re-used as raw material in the steel making process,leading to a significant reduction of the consumption of natural resources to decelerate the climate change and ensure a sustainable development.One of the business segments of Befesa Zinc S.L.U.,a subsidiary company of Abengoa,is the recycling of dusts and other residues containing nickel,chromium and molybdenum from the stainless steel industry.The technologies applied are submerged arc reduction smelting(Befesa Valera S.A.S.,Gravelines,France) and plasma reduction smelting(Befesa ScanDust AB,Landskrona,Sweden).Stainless steel plant dusts,mill scale and other residues are delivered in closed containers and big bags by ship,rail or truck and stored.After a preparation of the residues and charging into the pyrometallurgical furnace,the metal compounds contained in the charge are reduced to metals in the presence of the carbon added.At Befesa ScanDust,the regularly tapped liquid metal is cast in the form of granules via the Granshot~(?) granulation process.The granulated product has many advantages such as excellent preheating properties and fast melting when added to a metallurgical process.The granules size and shape also makes it very suitable to handle with most raw material handling systems.By granulating the so-called alloyed pig iron(API) a high metallic yield is achieved ensuring maximum recovery of metal and less new dust generation compared to a crushed material.The granules are redelivered to the stainless steel producers or sold on the open market.
The European stainless steel producers generate 20 -30 kg dust per ton of produced stainless steel. The dust formed during various stages of the production process contains valuable metals such as Cr, Ni and Mo. General this dust is considered as a hazardous waste. If not taken care of the dust will be an environmental risk causing potential problems such as leaching of heavy metals into groundwater and pollution of land and air. By applying techniques for recycling the dust the problem is minimized and valuable metals are recovered and re-used as raw material in the steel making process, leading to a significant reduction of the consumption of natural resources to decelerate the climate change and ensure a sustainable development. One of the business segments of Befesa Zinc SLU, a subsidiary company of Abengoa, is the recycling of dusts and other residues containing nickel, chromium and molybdenum from the stainless steel industry.The technologies applied are submerged arc reduction smelt ing (Befesa Valera SAS, Gravelines, France) and plasma reduction smelting (Befesa ScanDust AB, Landskrona, Sweden) .Stainless steel plant dusts, mill scale and other residues are delivered in closed containers and big bags by ship, rail or truck and stored . After a preparation of the residues and charging into the pyrometallurgical furnace, the metal compounds contained in the charge are reduced to metals in the presence of the carbon added. At Befesa ScanDust, the regularly tapped liquid metal is cast in the form of granules via the Granshot ~ (?) granulation process.The granulated product has many advantages such as excellent preheating properties and fast melting when added to a metallurgical process. The granules size and shape also makes it very suitable to handle with most raw material handling systems. By granulating the so-called alloyed pig iron (API) a high metallic yield is best ensured of metal and less new dust generation compared to a crushed material. The granulesare redelivered to the stainless steel producers or sold on the open market.