Classifications

• • 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
  • C22B15/006—Pyrometallurgy working up of molten copper, e.g. refining

Definitions

• This invention relates to a process for removing bismuth from copper or from melts and prod,- ucts containing it,
• Bismuth is one of the most feared impurities in copper, as a bismuth content of even only a few thousandths of one per cent exerts an unfavorable influence upon the mechanical properties of the copper, and contents of more than M percent render the copper useless for most purposes.
• the present invention consists in carrying out the metallurgical process in all its stages in such a manner that a final product is obtained which is practically free from bismuth, that is to say, contains about less than 0.002%.
• the bismuth is removed by treating the melt with silicic acid or silica or substances containing the same during the metallurgical process.
• the metallurgical process is carried out in its individual stages with a quantity of silicic acid which is always sufllcient to produce a removal of the bismuth which is as extensive as possible.
• a quantity of silicic acid which is always sufllcient to produce a removal of the bismuth which is as extensive as possible.
• the silicic acid is used in a state in which it is as reactive as possible, and in fact as finely ground as possible. silicates which have been decomposed by sulphuric acid can also be employed. The addition of the silicic acid may also take place with an addition of small amounts of alkali chlorides or alkali sulphates. The addition of silicic acid or of additions containing the same should be effected as uniformly as possible and the fused mass should uniformly come in contact with the same as well.
• the minimum amount of silicic acid also depends, therefore, apart from the amount of bismuth to be removed, upon the working conditions chosen and also upon the quality or condition and reactivity of the silicic acid itself.
• the amount therefore, must be chosen at least so large that 5 the bismuth is actually removed to an extent sufficient for the purpose in view.
• the improved process according to this invention is carried out for example as follows:.
• the rate of reaction and the temperature are suitably regulated. This may be effected, for instance, by addition of carbon or coal, preferably mixed with silicic acid, and 00 by introducing the same through the blow nozzles by means of the blast.
• the current of air must always be sufiicientiy strong to be able thoroughly to whirl up the contents of the converter. If this is effected solely l 05 by the blowing in of air, as is usual, then the amount of copper in the contents of the converter rises more quickly than is desirable for the vaporisation of thebismuth.
• the gas current consists then chiefly of the carbon oxides and nitrogen. If the addition of carbon is so large as to consume the entire oxygen of the air, or if oxygen-poor air, e. g. flue gas, is used, then the copper content can be 7 maintained at the same percentage, so that the Silicic ishing blowing of the melt to copper, by further additions of silicic acid.
• ferrosilicon is used partly or wholly in place of the silicic acid.
• additions of ferrosilicon are to be regarded all additions of substances or mixtures of substances which are capable of bringing about an intermediate formation of ferrosilicon in the fusion vessels themselves.
• a mixture of silicic acid and carbon (or coal) in the presence of.iron yields ferrosilicon at comparatively low temperatures.
• the step of adding silicic acid and carbon material to the copper-containing material at the start and also at intervals during the progress of the process the amount of silicic acid added being sufficient not only to slag the impurities, e. g. iron, but also to remove the bismuth, the amount of carbon added being sumcient to delay the formation of the higher oxides of iron until after the bismuth has been removed.
• a process as defined in claim 8 in which the silicic acid and carbon material are used in admixture with each other.
• the impurities e. g. iron

Landscapes

• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Manufacturing & Machinery (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Manufacture And Refinement Of Metals (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=7987641

Family Applications (1)

Country Status (3)

• 0
  • BE BE412851D patent/BE412851A/xx unknown
• 1935
  • 1935-12-19 US US55296A patent/US2155325A/en not_active Expired - Lifetime
  • 1935-12-20 FR FR799641D patent/FR799641A/fr not_active Expired

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