Metal oxides mineral processing

Flotation is certainly the major separation method based on the surface chemistry of mineral particles. It is, however, not the only method. Selective flocculation and agglomeration may be mentioned as other methods used commercially to a limited extent. The former is for hematite, while the latter is for coal and finely divided metallic oxide minerals. Both processes use the same principles as described for flotation to obtain selectivity. In selective flocculation, polymeric flocculants are used. The flocculants selectively adsorb on the hematite, and the hematite floes form and settle readily. Thereby separation from the sili-... 

PROBABLE FATE photolysis, not important oxidation Tl (III) present only in very oxidizing water. In reducing conditions, metallic Tl or sulfide may precipitate hydrolysis hydrolysis of tP to insoluble TI(OH)3 unimportant because of low Tr content of natural water volatilization data not available sorption Tl adsorbed strongly by clay minerals and to a lesser extent by hydrous metal oxides biological processes rapidly bioaccumulated by aquatic organisms... 

Zinc occurs most abundantly in tire mineral. Sphalerite, ZnS, which is roasted to produce the oxide before the metal production stage. The products of the roast are then reduced by carbon to yield zinc oxide and CO(g). In the older process, tire Belgian retort process, the metal oxide and carbon are mixed together in a reactor which allows the indirect heating of the charge to produce the gaseous products followed by tire condensation of zinc at a lower temperature in a zone of the reactor which is outside the heating chamber. The carbon monoxide is allowed to escape from the vessel and is immediately burnt in... 

Rather than reiterating what is well known about flotation of gold, PGMs and oxide minerals, emphasis has been placed on the separation methods which are not so effective when using conventional treatment processes. These difficult separation methods are largely attributed to problems with selectivity between valuable minerals and gangue minerals, especially in the flotation of oxide ores and base metal oxides, such as copper, lead and zinc oxide ores. 

In the deposits where oxide cobalt is present, it is common to have oxide copper minerals. The cobalt is, therefore, recovered in a bulk copper-cobalt concentrate that is processed using a hydrometallurgical technique to produce separate copper and cobalt metals. Oxide... 

Waite, T.D. (1986), "Photoredox Chemistry of Colloidal Metal Oxides", in J.A. Davis and K.F. Hayes, Eds., Geochemical Processes at Mineral Surfaces, Washington, ACS Symposium Ser. No. 323. 

Rates of reductive dissolution of transition metal oxide/hydroxide minerals are controlled by rates of surface chemical reactions under most conditions of environmental and geochemical interest. This paper examines the mechanisms of reductive dissolution through a discussion of relevant elementary reaction processes. Reductive dissolution occurs via (i) surface precursor complex formation between reductant molecules and oxide surface sites, (ii) electron transfer within this surface complex, and (iii) breakdown of the successor complex and release of dissolved metal ions. Surface speciation is an important determinant of rates of individual surface chemical reactions and overall rates of reductive dissolution. 

Weathering of snbsurface solid phases occnrs as a result of their direct interaction with liqnid phases, which may also in tnm be affected by the gaseous environment. Examples of weathering processes inclnde reactions that convert primary minerals snch as qnartz and clays into metal oxides and metal hydroxides. 

Sherman, D.M. (1985) Electronic structures of Ee " coordination sites in iron oxides application to spectra, bonding and magnetism. Phys. Chem. Min. 12 161-175 Sherman, D.M. (1987). Molecular orbital (SCF-Xa-SW) theory of metal-metal charge transfer processes in minerals I. Application to the Fe vpe charge transfer and electron delocalization in mixed-valenced iron oxides and si-licates.Phys Chem Min 70 1262-1269 Sherman, D.M. (1990) Crystal chemistry, electronic structure and spectra of Fe sites in clay minerals. Applications to photochemistry and electron transport. In Coyne, L.M. McKeever, S.W.S. Blake, D.F. (eds.) Spectroscopic characterization of minerals and their surfaces. A.C.S. Symposium Series 415, 284-309... 

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