Chemistry of inorganic compounds – Treating mixture to obtain metal containing compound – Radioactive metal
Patent
1983-03-07
1987-01-06
Terapane, John F.
Chemistry of inorganic compounds
Treating mixture to obtain metal containing compound
Radioactive metal
423 15, 423 55, 423 87, C22B 6002, C22B 3004
Patent
active
046345795
DESCRIPTION:
BRIEF SUMMARY
The present invention concerns a process for the selective removal of arsenical material in the form of magnesium arsenate in the course of a continuous process for the oxidising attack on a uraniferous and/or molybdeniferous ore containing arsenic as an impurity, by means of an aqueous liquor containing alkali metal carbonate and bicarbonate in solution, under conditions of concentration, temperature and pressure causing solubilisation of the uranium and/or molybdenum present in the ore.
It has long been known for the alkaline attack on uraniferous ores containing alkaline-earth metal carbonates such as calcium and magnesium carbonates in substantial quantities to be effected preferentially by means of an aqueous liquor of sodium carbonate and bicarbonate, the concentration of those two components in the liquor being increased in proportion to increasing refractoriness of the ore.
The attack operation is generally carried out in an oxidising medium which is produced for example by blowing free oxygen into the hot reaction medium in order to permit oxidation of the uranium and/or molybdenum and solubilisation thereof, but also to ensure oxidation of the sulphides of impurities, which are present in the ore.
However, it may happen that the uraniferous and/or molybdeniferous ores contain arsenic, which is a particularly troublesome impurity, a fraction of the arsenic being solubilised in the attack operation in the form of alkali metal arsenate, while the other fraction which occurs in a refractory arsenical form is unaffected by the attack operation and is removed with the sterile matter.
Hence, the absence of any treatment for removing the arsenic which is solubilised during the ore attack operation gives rise to major disadvantages which may have a detrimental effect on the quality of the materials produced.
In fact, the suspension resulting from the attack operation, when subjected to a separation operation, provides for recovery of liquid and solid phases.
The solid phase which is formed by sterile matter and the undissolved arsenical fraction is impregnated with the uraniferous and/or molybdeniferous liquor containing the arsenic resulting from the attack operation, and is then washed by means of water or an aqueous recycling liquor to recover the impregnation liquor.
The liquid phase which contains in solution alkali metal carbonate and bicarbonate, uranium and/or molybdenum, and arsenic which is solubilised in the attack operation, constitutes the production liquor which, when mixed with the liquor resulting from the operation of washing the solid phase, is subsequently treated by means known to the man skilled in the art to extract therefrom the uranium and/or molybdenum, before the liquor, after having had its uranium and/or molybdenum content removed in that way, is possibly recycled to one of the steps in the ore attack procedure.
The effect of recycling the liquor with its reduced uranium and/or molybdenum content to the ore attack operation, as referred to above, is a continuous and progressive increase in the proportion of arsenic in all the steps in the process for producing the uranium and/or molybdenum as a useful product, and in particular in the production liquor which is intended to extract the element or elements which are to form the useful product.
Accordingly, the proportion of arsenic in the uraniferous and/or molybdeniferous precipitate increases in a correlated manner and may be such as to prevent exploitation of the concentrate of the element or elements which are to form the useful product.
Hence, it is found necessary to carry out a process for the selective extraction of arsenic in such a way that uraniferous and/or molybdeniferous ores which contain that impurity in particular can be the subject of industrial exploitation.
Various treatment processes which are known to the man skilled in the art have been suggested in an effort to overcome the problem which arises by virtue of the presence of arsenic in the uraniferous and/or molybdeniferous production liquors.
A first proces
REFERENCES:
patent: 2079805 (1937-05-01), Judd
patent: 2951741 (1960-09-01), Sill
patent: 4272490 (1981-06-01), Sefton et al.
patent: 4366128 (1982-12-01), Weir et al.
patent: 4406864 (1983-09-01), Weir et al.
patent: 4423010 (1983-12-01), Maurel
Lamerant Jean-Michel
Maurel Pierre
Pallez Francois
Aluminium Pechiney
Caress Virginia B.
Terapane John F.
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