A. Ahlstrom Corporation

A. Ahlstrom Osakeyhtio

Outokumpu Engineering Contractors Oy

Rm Metal Consulting Ky

Rolf E Malmstrom

Stig Petersson

Hans I Elvander

Pekka O Ritakallio

Method and apparatus for treatment sulphidic concentrates

Method for reducing material containing metal oxide in solid phase

A method for roasting sulphide ores or ore concentrates containing precious metals is practiced in a furnace, typically in a fluidized bed. The ore and a sulphur-binding lime-containing material are supplied to a roasting furnace in which the ore is roasted with the emission of heat and sulphur dioxide. The lime-containing material--such as calcium hydroxide--is mixed into the cooling water for the roasting furnace and sprayed into the furnace as a lime-containing aqueous slurry. Roasting occurs at about 600-850.degree. C. (e.g. 650-750.degree. C.). Roasted material is discharged from the furnace and acted upon to recover gold, silver and copper metal.

Method for roasting sulphide ores

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.

Apparatus for treating zinc concentrates

A catalyst bed for conducting exothermal reactions between gases and/or other fluids is disclosed. The catalyst bed includes at least two cooling elements arranged in parallel relationship with each other. A space is thereby defined between the two cooling elements, and one opening at each opposite end of the cooling elements is also defined by the arrangement of cooling elements. The space created is adapted to receive a catalyst mass through either of the openings. The cooling elements cool the gases and/or other fluids, as well as the catalyst mass to keep the reaction temperature low enough to maintain a desired state of equilibrium.

Catalyst bed for exothermal reactions between gases and/or other fluids

Method and apparatus for treating zinc concentrates

The invention relates to a method of improving the heat recovery in a waste head boiler, in which gas, produced in high-temperature processes and containing molten and/or solid particles and/or evaporated components, is cooled. In a waste heat boiler, a slowly cooling zone, i.e. a hot 'tongue' is generally formed in the gas flow. To improve the cooling of the hot 'tongue', gas and/or solid particles and/or vaporizing liquid, such as circulating gas or circulating particles separated from the process and cooled, are introduced into the hot zone or 'tongue'.

Method of recovering heat from hot process gases

Method and apparatus for producing matte and/or metal from sulphidic fine-grained ore or ore concentrate. The ore or ore concentrate is smelted in a flame chamber in such a way that at least part of the solid material in the flame chamber melts and flows downward into a smelt bath furnace, on top of which the flame chamber is disposed. Volatile metallic and sulphuric components are conducted upward from the flame chamber to a fluidized bed reactor to be utilized as fluidizing gas, the gases being rapidly cooled down in the fluidized bed.

Method and apparatus for producing matte and/or metal

A method and apparatus for producing, in a reactor, a suitable prereduced product for final reduction from material containing metal oxide. The material is preheated in a fluidized bed by means of hot gases from a subsequent prereduction stage. The hot material is smelted and prereduced in a flame chamber utilizing hot reducing gases from a subsequent final reduction stage. The prereduced material is completely reduced in the final reduction stage.

Method for reduction of material containing metal oxide using a

The invention relates to a process for the refining of sulfidic concentrates which contain arsenic, antimony and bismuth, wherein a suspension of the sulfidic concentrate and oxygen or oxygen-enriched air is introduced into the upper part of a reaction zone, in the lower part of which the direction of the gases is deflected sidewards in order to cause the molten and solid particles traveling along with the gases to impinge against the surface of the melt below the reaction zone. In order to form a molten or semi-solid phase, concentrate, oxygen or oxygen-enriched air, and a carbon- or sulfur-containing fuel are introduced into the reaction zone in such proportions that in the upper part of the reaction zone there is formed an atmosphere containing sulfur and sulfur dioxide and having a temperture above 900.degree. C. and a maximum oxygen pressure of 10.sup.-6 atm in order to volatilize the arsenic, antimony and bismuth, and possibly the lead and zinc. During the same stage, air or oxygen-enriched air is fed into the lower part of the reaction zone in order to oxidize the concentrate to the desired metal concentration.

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Helsingfors, Finland

Rolf E Malmstrom