Classifications

• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
  • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
  • C21C5/28—Manufacture of steel in the converter
  • C21C5/30—Regulating or controlling the blowing
  • C21C5/34—Blowing through the bath
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B13/00—Obtaining lead
  • C22B13/02—Obtaining lead by dry processes
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B15/00—Obtaining copper
  • C22B15/0026—Pyrometallurgy
  • C22B15/0028—Smelting or converting
  • C22B15/003—Bath smelting or converting
  • C22B15/0041—Bath smelting or converting in converters
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B23/00—Obtaining nickel or cobalt
  • C22B23/02—Obtaining nickel or cobalt by dry processes
  • C22B23/025—Obtaining nickel or cobalt by dry processes with formation of a matte or by matte refining or converting into nickel or cobalt, e.g. by the Oxford process
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B9/00—General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals
  • C22B9/05—Refining by treating with gases, e.g. gas flushing also refining by means of a material generating gas in situ
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B9/00—General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals
  • C22B9/10—General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals with refining or fluxing agents; Use of materials therefor, e.g. slagging or scorifying agents
  • C22B9/103—Methods of introduction of solid or liquid refining or fluxing agents

Definitions

• the invention relates to methods of treating metals in molten baths which involve injecting oxygen through the bottom of a tank containing the molten metal. This type of process is applied in particular in the refining of metals from concentrated ores for the manufacture of steel by refining of cast iron.
• the present invention provides a method of treating a metal in a molten bath according to which a reactive product with oxygen is pneumatically introduced into a bath of molten metal at the same time as injecting the oxygen in this bath, which consists of the injection of oxygen in the form of a jet adjacent to a jet of protective gas, while the reactive product is conveyed in the molten metal in sprayed form in said protective gas jet.
• the method according to the invention can be applied in this form to all kinds of metal treatments in molten baths, whether in particular refining of cast iron or treatment of ores such as lead sulfide.
• the adjacent jets can in particular be in contact with each other over their length, one of the jets being for example surrounded by the other.
• the pulverized product introduced into the molten bath may in particular be a product which oxidizes in the presence of oxygen, unless it is diluted in an inert gas such as nitrogen, or which forms an explosive mixture with any gas essentially consisting of 'oxygen.
• This product can in particular be a flux useful for a refining reaction or another product participating in the desired reaction, such as concentrates of metal ores.
• the flux or the ore and the oxygen are conveyed directly into the reaction zone with the oxygen inside the molten metal, so that the reaction can take place. perform efficiently and safely without significant erosion of the refractory lining containing the molten metal bath.
• the oxygen jet can be surrounded by the protective gas jet or the protective gas jet can be surrounded by the oxygen jet.
• the oxygen jet it is advantageous for the oxygen jet to be further surrounded by a second jet of protective gas, so as to avoid deterioration of the refractory lining.
• the protective gas can for example be constituted by a hydrocarbon, and in particular a gaseous hydrocarbon such as propane, by another gas such as sulfur dioxide, carbon monoxide, carbon dioxide, nitrogen, vapor d water or argon, or any other fluid behaving in a manner substantially inert in the oxidation reaction and not involved in the metal refining process.
• a hydrocarbon such as propane
• another gas such as sulfur dioxide, carbon monoxide, carbon dioxide, nitrogen, vapor d water or argon, or any other fluid behaving in a manner substantially inert in the oxidation reaction and not involved in the metal refining process.
• the process according to the invention applies in a very particularly advantageous manner to the production of metals such as lead, cobalt and copper from the concentrates of the corresponding sulfides, but it can also be used for the treatment of other metallic ores giving rise to too strong a reaction in an oxygen jet.
• oxygen is used in the form of oxygen diluted in air, this has the disadvantage of requiring additional heat to be consumed by the refining reaction, and therefore of adversely affecting the economic profitability of the operation.
• a lead sulphide concentrate containing the following main constituents in the indicated weight proportions: lead 72%, sulfur 15%, copper 1%, iron 3%, C0 2 3%
• the reaction requires 0, 16 m 3 of oxygen for 1 kg of concentrate for the operation to be complete.
• the concentrate is conveyed pneumatically to an oxygen reaction zone located within the liquid lead bath.
• the concentrate is entrained by the protective gas in the annular jet which surrounds the oxygen jet.
• the quantity of protective gas necessary to thus entrain 1 kg of concentrate is advantageously of the order of 0.001 to 0.05 m.
• This volume of protective gas can vary within very wide limits and the proportion used can in fact be chosen so as to maintain the desired thermal balance while remaining within the range suitable for pneumatic transport.
• the injection nozzles comprise three concentric tubes forming between them two annular intervals around the central jet.
• the internal tube is used to convey the jet of flux or metallic ore in an inert gas, in particular in a protective fluid as described above.
• the annular space between the inner tube and the intermediate tube is used for the gaseous oxygen ensuring the refining reaction and the annular space between the intermediate tube and the tube external is used to conduct a protective gas which prevents the attack of the wall of refractory material constituting the internal lining of the converter.
• the protective gas of the outer ring can naturally be of the same nature as that of the central jet. It prevents the reaction caused by oxygen in contact with the bath from occurring as soon as it leaves the nozzles.
• the metal ore concentrate To be admitted into the central jet, and as in the case of the annular jet of the previous embodiment, the metal ore concentrate must be reduced in powder form, with particle sizes generally less than 1 mm, while in prior techniques it was used in a coarser form to be introduced over the bath.
• the invention is not limited to the specific applications envisaged by way of examples. And it is understood that the method according to the invention can be applied with advantage in all cases where it is useful to admit a reactive solid product at the same time as oxygen in a molten metal bath.

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Citations (9)

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• 1979
  • 1979-10-31 CA CA000338906A patent/CA1141175A/en not_active Expired
• 1980
  • 1980-10-06 US US06/194,621 patent/US4315774A/en not_active Expired - Lifetime
  • 1980-10-31 EP EP80401551A patent/EP0028968A1/de not_active Withdrawn
  • 1980-10-31 AU AU64025/80A patent/AU6402580A/en not_active Abandoned
  • 1980-10-31 JP JP15236980A patent/JPS5681642A/ja active Pending

Patent Citations (9)

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