Flotation properties of esters of polyhydric alcohols and carboxylic acids the flotation of apatite-carbonate ore

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SYSTEMS:UDC 622. 765,4~622.364 The rate of selective flotation of a mineral from an ore is ultimately determined by the rate of formation of mineralized foam from the flotation aggregates (aeroflocculation). In these processes great importance attaches to the structure of the foam, which depends on the compositions and structures of the flotation reagents, the grain size of the flotated mineral, the degree of dispersity of the air, and the hydrodynamic conditions in the flotation cell.In [1,2] it was shown that coalescence in the slurry of a fotation aggregate (aerofloccule) may lead to the formation of various mineralized foams, differing in their properties and morphological features. Limited structural coalescence of liquid films easily leads to the accumulation of flotation aggregates and the formation of dense foam-aggregates; and, if there is a marked tendency to this coalescence, film-structured foams will be formed.Klassen [3] discusses the conditions for the formation of a flotation aggregate in connection with active adhesion of micro-bubbles of air to the mineral surfaces, and the significance of the properties of foams of various structures in the flotation of coals.Berger [4,5] showed that the formation of aggregate foams is an effective means of selective flotation of many slightly hydrophobized minerals.Typical aggregate foams are not capable of any appreciable subsequent flocculation: this explains their long lives in closed vessels, where they may last for months without visible change. Qualitatively, their structural and mechanical properties are analogous to thixotrop~ on agitation, up to the detachment of part of the aggregate, they become very mobile and recover their original high viscosities for as long as the agitation continues.In their original states, film-structured foams are not very long-lived~ and easily decompose into their structural elements. In many cases their decomposition does not go to completion, and we are left with a foam which we must regard as flocculated. All mixed foams, consisting of regions where structural coalescence is developed and regions where it is weak, are easily subjected to floceulation and then form dense foams containing smaller air bubbles than those in the original foam. Such foams are formed, over wide dispersity ranges, in industrial cells.

Formation and properties of dispersive flotation systems: Flotation of apatite

Aleinikov¹,

Golovanov²,

Aleinikova³

1966

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Flotation properties of esters of polyhydric alcohols and carboxylic acids the flotation of apatite-carbonate ore

Aleinikov¹,

Ivanova²

1967

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ALCOHOLSUDC 622.765.06Nonionic compounds of relatvely low molecular weight and with a small number of hydrophilic groups can have a marked effect on the selective flotation of nor.sulfide minerals from ores by carboxylic acids. The range of such compounds includes hydroxyethyl carboxylic acids [1], hydroxyethyl aliphatic alcohois, alkanolamides of carboxylic acids [2], hy~oxyechyl alkyIphenols [3], and the complexes formed from these nonionic compounds and high-molecular substances [4,5].Aqueous emulsions or suspensions of such compounds can have a hydrophilizing effect when added to a pulp, owing to specific sorpton (on the surface) of hydrophobicized (orsubsequenfly hydrophobicized) minerals of u~e ore by carboxyHc acid. Owing to the different degrees of surface hydrophilization, effective selective flotation of one of the minerais becomes feasible. The dimensions of the flotatonaggreg~es(aeroflocculi) formed in the pump decrease and thek content of selectively floamble mineral increases. The mineralized froth formed has all the propertes of flocculated froths [6].Owing to the changes which they cause in dispersed flotation systems, these reagents have been called deflocculants. It has been found that deflocculants do not have selec~ve properties. At high consumptions (0.25-1 kglr we observe in some cases the appearance of froth-forming properties without a marked yield of the floatable producr. The high conmnt of hydrophUic groups in the deflocculant molecule leads to undesirable froth formation and loss of selectivity.The present paper deals with the flotation properties of nonionic compounds obtained by esterification of carboxylic acids and Polyhydric aliphatic alcohols. In a previous paper [8] we suggested that the commercially important esrerificaton product s [7] were suitable for selective flotation of apatite from ores with various mineralogical compositions.Esterificatlon was performed by heating a mixture of 1.2 moles of alcohol and 1 mole of carboxyli c acid in nitrogen at 140-170" in ~he presence of phosphoric acid as catalyst (1-2 wu~o of the reaction mass) [9,10]. Esterification was considered complete when the reaction mass had minimum acid number and the product employed directly for flotation as aqueous 1~ emulsions or suspensions; to prepare these, 30 mg of soda Per 100 ml of solution was added. Table 1 gives the esters thus obtained.From ~be values of their este~ numbers, the esteRfication products can be considered as monoesters of dehydrated alcohols or as mixtures of mono-and diesters.For the flotation experiments we used the nonmagnetic fraction of Kovdor iron ore, containing mainiy apa~m, carbonates, forsterite and mica (Table 2); it is therefore an apatim-carbonam ore [5,11]. In the nonmagnetic fracton, crushed to flotation size (Table 3), chemical and mineralogical analysis dam reveal a smady increase in the carbonate content in u~e fine classes as we go from the +0.3 to the 0.05 mm material The apatire content in u~e +0.3 and +0.2 mm mamzial is low and the other size classes contain ...

Selective flotation of phosphate-carbonate ores

Aleinikov¹,

Afanas’eva²

1971

To study the effect of complex depressants of nonionogenic compounds on selective flotation of apatite from carbonate-rich ores, we used the nonmagnetic fraction of iron ore of the Kovdor deposit. The use of such depressants was proposed in [1,2] and then developed further in [3,4].The nonmagnetic fraction, crushed to a flotation-type grain size and virtually free of intergrowths, had the grain-size characteristics shown in Table 1. The product contained about 30~ apatite, 35% calcite, 6% dolomite, 20% forsterite, and 7% mica (phlogopite and hydrophlogopite). The large size classes had a high mica content, which was also characterized by a high MgO content. The maximal content of apatite, carbonates, ~nd forsterite was observed in the -0.074 mm class; the carbonates were overcrushed and their content tn this size class reached 48 wt.%.