Effect of ore dressing on flotation of copper and arsenic minerals in sulphide ore processing

Monomineral flotation results showed that the use of a new reagent S-cyanoethyl N, N-diethyldithiocarbamate enhances the flotation activity of chalcopyrite, in contrast to flotation with butyl xanthate, and reduced the flotation ability of arsenopyrite, which makes this reagent promising for its use in the selective flotation of complex sulfide ores.

STUDYING OF CONNECTION OF HYDROCARBON FRAGMENT OF COLLECTOR WITH ITS FLOTATION ACTIVITY

High flotation activity of collector when additional hydrophilic group is implemented in its structure of hydrocarbon fragment does not have explanation in thermodynamic description of the elementary act of flotation. An assumption is made that the presence of hydrophilic group promotes connection establishing of energetic links between hydrocarbon fragment of reagent and water molecules. As a result, speed of spreading of physical form of reagent sorption on “gas-liquid” interface, when flotation complex forms, increases. Connection between flotation activity of collector, its structure and composition and power of surface flow of its physically sorbed forms is established.

RATIONAL PROCESSING OF REFRACTORY COPPER-BEARING ORES

The paper presents the results obtained when studying material compositions of four samples of refractory copper-bearing ores from the Uzelga deposit along with technological solutions to improve their processing parameters. The refractoriness of ores is associated with a thin dissemination (up to a micron size) and close intergrowth of ore and rock minerals. Ferrous sulfides are represented by a wide range of minerals: pyrite, marcasite and their variety melnikovite, arsenic pyrite and arsenopyrite; sooty melnikovite has a higher flotation activity. The reduction of iron sulfides from 89 to 29 % is followed by a proportional increase of easy-floatable rock minerals to 45 % and clay to 9 %. These properties make these sulfides difficult to process (float) and maintain ore refractoriness. The content of copper sulfides in ore samples varies from 3,32 to 7,29 %; the relative fraction of copper sulfide in a form of tennantite in different deposit samples varies from 29 to 93 %. Copper is also present as chalcopyrite and bornite. The best flotation activity of tennantite can be seen in neutral and weak acid media in contrast with standard flotation mode for chalcopyrite and bornite with butyl xanthate in a high-alkaline calcareous medium. Free grains of copper minerals can be selectively extracted into the intermediate flotation copper concentrates when grinding maximum 60 % of the –71-μm class. The technology of flotation in a low-alkaline medium is developed for refractory copper-bearing ores with variable tennantite content using the M-TF selective sulfhydryl collector in intermediate copper flotations and copper concentrate upgrading cycle; aeration used to suppress melnikovite flotation activity makes it possible to achieve 80 % copper recovery into conditioned copper concentrate. Bornite, tennantite, chalcopyrite and sphalerite disseminated in pyrite make it rational to obtain copper-pyrite, copper-zinc-pyrite products with their yield up to 12 % for pyroand hydrometallurgical processing.

Synthesis and flotation activity of reagent-collectors based on dithiocarbonyl and phosphoryl derivatives of amino alcohols

Research has been carried out to study flotation activity of new surface active substances among dithiocarbonyl and phosphoryl derivatives of monoethanolamine and diethanolamine on the gold-bearing sulphide ore of the Bestobinskoye deposit of Kazakhstan. Among the synthesized compounds, effective collectors for selective enrichment of sulfide polymetallic gold ores were found. Sodium N-octyl-N-2-hydroxyethyldithiocarbamate (AA-41) and sodium O-2-(dimethoxyphosphoryl- 2-hydroxyethylamino)ethylxanthate (GF-2) were proposed as new flotation reagents. They were tested in flotation of gold-bearing polymetallic ore as additional collectors contributing to an increase in percentage of gold extraction in the collective concentrate in comparison with the factory basic regime in which a mixture of butyl xanthate (BX) and ditiophosphate butyl ether or butyl airoflot (BAF) was used. The results of flotation tests indicate that collective ability of GF-2 in combination with BAF provides a higher gold recovery to the concentrate – 90.8%, than gold recovery with BX and BAF is (87.7%). It should be specially emphasized that consumption of GF-2 in comparison with BX is lower on 33%. Synthesis methods of the AA-41 and GF-2 flotation agents were developed, and evidence of their structure was given by IRS and NMR 1Н, 13С. The principal technological scheme of GF-2 obtaining was developed. In synthesis of collector AA-41, one of the principles of “green” chemistry “catalytic systems and processes (as selective as possible) are in all cases better than stoichiometric ones” was used. The use of tetrabutylammonium iodide as catalyst in synthesis allows shorten the reaction time, reduce reaction temperature and increase the selectivity.