Abstract: A process and an apparatus are disclosed for improved recovery of metal from hot and cold dross, wherein a dross-treating furnace is provided with a filling material with capacity to store heat. This filling material is preheated to a desired temperature by injection of an oxidizing gas to burn non-recoverable metal remaining in the filling material after tapping of the recoverable metal contained in the dross and discharging of the treatment residue. When dross is treated in such furnace, the heat emanating by conduction from the filling material is sufficient to melt and separate the recoverable metal contained in the dross, without addition of an external heat source, such as fuel or gas burners, plasma torches or electric arcs and without use of any salt fluxes. Furthermore, the recovered metal being in the molten state can be fed to the molten metal holding furnace without cooling the melt.

Abstract: The invention relates to a method for reducing and/or refining a metal-containing slag. The aim of the invention is to improve reduction of the slag. For this purpose, calcium carbide (CaC2) is added to the slag as the reducing agent.

Abstract: A method for processing converter slag produced in copper smelting includes feeding the converter slag into a reducing furnace, reducing zinc and copper contained in the converter slag by heating and removing the reduced zinc through volatilization in a reducing furnace. The slag discharged from the converter is transformed into a raw material for iron making.

Abstract: A method and apparatus for substantially smoke free separation and recovery of zinc from galvanizing skimmings and for refining the resulting ash to a by-product form. An essentially closed housing defining a skimmings receiving chamber and a skimmings processing chamber with a bottom opening is placed on or above a galvanizing kettle and extends into the molten zinc of the kettle so that molten zinc is present with a skimmings processing chamber. A motor driven agitator shaft having paddles is rotated within the skimmings processing chamber so that the ends of the paddles enter the molten zinc during each shaft revolution and enhance melting and recovery of the zinc.

Abstract: A recycling process for zinc-rich solid waste containing zinc oxide, Cu oxides and impurities normally present in brass, in which a mixture is formed containing the waste with a finely divided solid reducing agent and a binder, and the mixture is compacted as agglomerates with open pores. The agglomerates are added into a treatment reactor containing a bath of liquid copper or brass metal, in which the zinc and copper oxides are reduced, to obtain in the treatment reactor after the reduction, a new brass in liquid form and a new waste. The new liquid brass is transferred into a fusion and casting furnace, in which its composition is optionally adjusted, and the new liquid brass is cast to form a product. Any waste present in the treatment reactor and the casting furnace are recycled using this process.

Abstract: A process and apparatus are disclosed for recovering a non-ferrous metal, preferably aluminum and aluminum alloys, in molten coherent form from a charge of material to be processed containing the metal. The charge is introduced into a sealable furnace which is then sealed. The charge is agitated. A control parameter indicative of conditions inside said furnace is monitored and compared to a pre-determined first condition for the parameter. A heat source is operated to heat the charge until the control parameter reaches the first condition. The operation of the heat source is then stopped. A controlled amount of oxidizing agent and an inert carrier is then introduced into the furnace. The control parameter is monitored and compared to a predetermined second condition for the parameter. The flow of the oxidizing agent and the carrier is controlled to maintain the control parameter at about the second condition. The molten metal is subsequently removed from the furnace.

Abstract: A method for submerged injection of materials into a liquid pyrometallurgical bath by means of a lance, characterised in that a first gas consisting of or containing oxygen is conveyed to said bath along a first path within the lance, a combustible fluid is conveyed to said bath along another path within the lance, and a further gas consisting of or containing oxygen is conveyed to said bath along a further path within the lance, the first path being arranged so that the first gas acts as a coolant for the lance.

Abstract: The invention relates to a method for utilizing zinciferous waste from metal smelters, such as steel smelters, so that the transmission of fluorides to the highly zinciferous secondary dusts is prevented during the treatment of the gas obtained from the waste smelting furnace. Fluorides are extremely harmful for the zinc process, and therefore it is important to prevent them from entering the process. By adjusting, according to the invention, the temperature and composition of the exhaust gases created in the smelting treatment of zinciferous dusts and other waste, the fluorides and the highly zinciferous fraction are obtained in different end products. Other valuable metals are recovered from the metal layer created on the bottom of the furnace.

Abstract: Zinc is recovered from zinc sulphide material by introducing such material at a feed station into a molten copper sulphide matte which is circulated in a closed loop path through said feed station, a zinc recovery station and an oxidizing station. The matte is heated electrically directly by resistive heating. Oxygen in the absence of other gases is introduced at the oxidizing station. Sulphur dioxide is removed in a sulphuric acid plant. The method is operated to keep the activity of copper in the total matte at less than unit activity. Virtually zero gas emission is possible.

Abstract: A method and apparatus for treating zinc concentrates in order to recover zinc. The method includes an oxidizing and smelting stage (10) and, subsequent to the smelting stage, a fuming stage (20) in which the zinc-oxide-containing slag formed in the smelting stage is so reduced as to remove the metallic zinc with the exhaust gases (28). Part of the reduced slag is discharged during the fuming stage, another part (32) is recirculated to the smelting stage. In accordance with a preferable method, the slag is reduced in two successive fuming stages (20, 40). In an apparatus according to the invention, the slag circulation between the fuming and smelting stages is facilitated by overflows arranged in the partition walls (19) between the various stages.

Abstract: A method and apparatus for treating zinc concentrates in order to recover zinc. The method includes an oxidizing and smelting stage (10) and, subsequent to the smelting stage, a fuming stage (20) in which the zinc-oxide-containing slag formed in the smelting stage is so reduced as to remove the metallic zinc with the exhaust gases (28). Part of the reduced slag is discharged during the fuming stage, another part (32) is recirculated to the smelting stage. In accordance with a preferable method, the slag is reduced in two successive fuming stages (20, 40). In an apparatus according to the invention, the slag circulation between the fuming and smelting stages is facilitated by overflows arranged in the partition walls (19) between the various stages.

Abstract: Spent oxidic catalyst, such as vanadium pentoxide from a sulphuric acid manfacturing process, is rendered into an environmentally acceptable non-leachable form suitable for disposable by incorporation into a vitrified amorphous slag formed of oxidic slag forming agents such as CaO, SiO.sub.2, FeO and Al.sub.2 O.sub.3. The vitrified slag may be formed as part of a conventional ferrous or non-ferrous smelting process, or may employ a pre-existing slag from such a process.