摘要:

The activation of sulphide minerals by heavy metal ions in acidic pH solutions has been reviewed from an electrochemical point of view. It is shown that the well-documented ion-exchange model is oversimplified. Surface oxidation of the mineral and reduction of the activator metal ions occur during the activation processes. Activation in an oxygen-deficient system leads to the formation of a sulphur-rich surface and results in activation-induced flotation. The overall process of activation is controlled by a mixed-potential mechanism.

ISSN:0882-7508    

DOI:10.1080/08827508908952635

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The activation of sulphide minerals by heavy metal ions at medium to alkaline pH solutions is reviewed. The pH-dependent characteristics of adsorption are identically indicated by adsorption isotherms, surface potential and flotation responses. The mechanisms involved are explored. It is found that the initial adsorption process is controlled essentially by surface precipitation of the activator hydroxide. The real activation of flotation is obtained during the second stage—the surface conversion step. The industrial practice of activation and flotation with a highly alkaline solution highlights the proposed model and mechanisms. The mechanism underlying the intermediate pH depression of flotation of the activated mineral is discussed.

ISSN:0882-7508    

DOI:10.1080/08827508908952636

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The present paper briefly describes the methods of gold ore processing and the associated problems are grouped into mineralogical, chemical and physical. The processing of low grade gold ores by heap leaching is an important technological development. But a major drawback in heap leaching process is low recovery of the precious metals. The problems that generally lead to a low gold recovery and the possible solutions are discussed.

ISSN:0882-7508    

DOI:10.1080/08827508908952637

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Laboratory scale autoclave leaching of Uludag scheelite flotation concentrate containing 24.5% WO3obtained from Etibank Corporation of Turkey was carried out. The effects of experimental parameters—amount and initial concentration of Na2CO3, temperature, particle size and time—on the recovery of WO3were studied. The concentrate had to be heated to around 650°C initially to drive off the organic flotation chemicals. To achieve 99% WO3recovery four limes the stoichiometric amount of Na2CO3was necessary within four or five hours at 220°C. Lower temperatures and lower Na2CO3amounts decreased the recovery. Highest recoveries were obtained with around 200 g/𝓁 initial Na2CO3concentration. It was possible to leach the concentrate with +93% WO3recovery using three times the stoichiometric Na2CO3amount at 220°C when particle size was reduced. Iso-extraction contour diagrams were drawn to illustrate the effects of various parameters on leaching.

ISSN:0882-7508    

DOI:10.1080/08827508908952638

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

This paper is concerned with a review of published literature on the processing of difficult-to-treat ferrous and nonferrous ores that have very fine liberation size and have constituent minerals with similar properties for which the conventional mineral processing techniques are ineffective. By altering mineralogy either pyrometallurgically or hydrometallurgically, the low cost methods of mineral processing could be applied on ores which are complex and refractory in character.

ISSN:0882-7508    

DOI:10.1080/08827508908952639

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Flotation of microorganisms is reviewed while at the same time recent developments in use of these organisms to concentrate heavy metal ions arc noted. Consideration is given to the nature of the organisms' surfaces and how these surfaces should influence their flotation characteristics. Past work on the electrokinetic properties of microorganisms is reviewed. The potential effect of heavy metal ions on surface and flotation properties of the organisms is discussed. Although work has not been performed to date on combining microorganism concentration of metal ions with froth flotation, the combination may prove to be an attractive means of treating metal containing waste streams.

ISSN:0882-7508    

DOI:10.1080/08827508908952640

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor