Classifying – separating – and assorting solids – Fluid suspension – Liquid
Patent
1996-03-01
1998-02-24
Lithgow, Thomas M.
Classifying, separating, and assorting solids
Fluid suspension
Liquid
209167, 252 61, 252357, B03D 102, B03D 101
Patent
active
057208735
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a method of floating calcium carbonate ore containing silicates as impurities. According to the invention, flotation is performed in the presence of a quaternary ammonium compound and an alkylene oxide adduct of an amine compound, the silicate being concentrated in the float.
From U.S. Pat. No. 4,995,965 it is known to separate calcium carbonate from impurities, such as silicate, by the steps of floating the silicate and concentrating the valuable mineral, i.e. the calcium carbonate in the remainder, in the presence of amine-group containing collectors. From this patent specification appears that a number of cationic compounds, such as methyl-bis(2-hydroxypropyl)-cocoalkyl ammonium methyl sulphate, dimethyl didecyl ammonium chloride, dimethyl-di(2-ethylhexyl)-ammonium chloride, dimethyl-(2-ethyl-hexyl)-cocoalkyl ammonium chloride, dicocoalkyl dimethvi ammonium chloride, and n-tallow alkyl-1,3-diamino propane diacetate can be used as collectors in such a flotation procedure. The patent specification also states that quaternary ammonium compounds, as represented by Arquad 2C (dimethyl dicocoalkyl ammonium chloride) and a combination of Duomac T (N-tallow alkyl-1,3-diamino propane diacetate) and Ethomeen 18/16 (long-chain alkylamine+50 EO) can be used as collectors, although they yield an unacceptably high content of acid-insoluble matter in the valuable mineral.
It has now surprisingly been found that when cleaning calcium carbonate containing silicates as impurity, a very high yield and/or high selectivity (low content of acid-insoluble matter) can be achieved if reverse flotation is performed in the presence of a quaternary ammonium compound in combination with an alkylene oxide adduct of an amine compound. More specifically, the present invention relates to a froth-flotation process performed in the presence of a quaternary ammonium compound having the formula ##STR1## wherein one or two of the groups R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are a hydrocarbon group having 8-36 carbon atoms and the remaining groups a hydrocarbon group having 1-7 carbon atoms or a hydroxyalkyl group having 2-7 carbon atoms, and A is an anionic counterion, and an alkylene oxide adduct having the formula ##STR2## wherein R.sub.5 is a hydrocarbon group having 8-22 carbon atoms, A.sub.1, A.sub.2 and A.sub.3 are an alkylene oxide group having 2-4 carbon atoms, R.sub.6 is an alkylene group having 2-3 carbon atoms, n.sub.1, n.sub.2 and n.sub.3 are 3-20 and the sum of all n.sub.1, n.sub.2 and n.sub.3 is 10-40, and s is 0-3; the weight ratio of the quaternary ammonium compound to the alkylene oxide adduct being 3:2-11:1, preferably 7:3-9:1, and calcium carbonate being recovered from the remainder while contaminating silicates are removed with the float. By the method of the invention, it has now been found possible to significantly reduce the content of insoluble silicates, such as quartz, feldspar, amphibole and pyroxene. In formula (I), two of the groups R.sub.1, R.sub.2, R.sub.3 and R.sub.4 preferably consist of straight or chained, saturated or unsaturated alkyl groups having 8-22 preferably 10-16 carbon atoms, while the two remaining groups preferably are alkyl groups having 1-3 carbon atoms or hydroxyalkyl groups having 2-3 carbon atoms. A generally is a monovalent ion, such as methyl sulphate or chloride. Specific examples of compounds of formula (I) are dimethyl didecyl ammonium chloride, dimethyl dicycloalkyl ammonium chloride, dimethyl dilauryl ammonium chloride, dimethyl distearyl ammonium chloride, dimethyl ditallow alkyl ammonium chloride and corresponding methyl sulphate salts. Alkylene oxide adducts of formula (II) preferably are such where R.sub.5 is a straight or branched, saturated or unsaturated alkyl group having 10-20 carbon atoms and the sum of all n.sub.1, n.sub.2 and n.sub.3 is 12-30. Of all the alkyleneoxy groups in the alkylene oxide adduct, 70-100% preferably are ethyleneoxy groups and 0-30% propyleneoxy groups. For reasons of production technique, such compounds are generally
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Derwents abstracts, No. C90-098166/13.
International Search Report, dated Aug. 26, 1994.
Klingberg Anders
Olsson Lisbeth
Akzo Nobel nv
Lithgow Thomas M.
Mancini Ralph J.
Morris Louis A.
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