Paper No.220
FLOTATION CHARACTERISTICS OF A COMPLEX COPPER ORE: A COMPARISON BETWEEN WET AND DRY GRINDING Saeed Farrokhpay1, 2,* and Hamid Reza Manouchehri1, 3 ABSTRACT It is known that the grinding condition has a major effect on the beneficiation characteristics of the minerals in subsequent processing, in particular, flotation. In the flotation process, particles surface and their condition can significantly influence collector adsorption and flotation performance. For example, particle shape and its surface roughness occurred during grinding may influence flotation characteristics of a specific ore. In fact, adsorption of different cationic and anionic species on mineral surfaces can be varied depending on the selected comminution procedure. The flotation performance of sulphide minerals can be detrimentally affected by the surface oxidation. The amount of surface oxidation may reduce the hydrophobicity of the mineral and makes adsorption of collectors less selective. Improved liberation may generally result in improved flotation recovery. However, this may result in finer grinding and slimes, and consequently, reduce the overall flotation recovery. This paper discusses the effect of wet and dry grinding on copper flotation of a complex Cu-Pb-Zn ore. Industrially, wet grinding is preferred due to its higher energy efficiency and owing to downstream processing requirements. In this study, series of flotation tests were conducted,and surface analysis (XPS and ToFSIMS) were performed after wet or dry grinding at two different P 80 values. Mineralogical study was also conducted to investigate the liberation of valuable minerals after grinding. A higher copper flotation recovery was found for wet grinding. However, the copper recovery was increased by further grinding in both conditions (wet and dry). The results showed a higher collector adsorption on copper mineral surfaces after wet grinding. The surface analysis also revealed that the ore is slightly more oxidized after dry grinding probably due to higher temperature during dry grinding. Keywords: sulphide ore, flotation, wet grinding, dry grinding, copper recovery
INTRODUCTION In ore preparation for flotation, various grinding procedures are industrially applied. These methods may affect the flotation performance due to variation in liberation, particle size and size distribution, or surface characteristics of the ore sample. For valuable mineral liberation, it has been shown that the particle composition distribution of a given size fraction after grinding is constant (for that mineral), regardless of the grinding method or the overall size distribution (Palm et al, 2010). However, it has also been shown that grinding environment and media may play a significant role in both flotation recovery and selectivity. For example, ceramic mill can produce an oxidizing environment, allowing sphalerite activation by copper ions, while steel media produces a reducing environment and prevents this action (Wei and Sandenbergh, 2007). Industrially, wet grinding is often preferred because most subsequent processes such as flotation and leaching are performed wet. However, in areas where water is scarce or where a dry process is followed after comminution, dry grinding may be preferred. It should be noted that wet grinding requires less power per ton of material ground than dry grinding. Wet grinding also does not require elaborate dust control equipment.
1. Ian Wark Research Institute, University of South Australia, Mawson Lakes SA 5095, Australia. 2. Currently: JKMRC, The University of Queensland, 40 Isles Road, Indooroopilly, Qld 4068, Australia. Email:
[email protected]. 3. Sandvik SRP AB, SE-233 81, Svedala, Sweden. Email:
[email protected].
XXVI INTERNATIONAL MINERAL PROCESSING CONGRESS(IMPC) 2012 PROCEEDINGS / NEW DELHI, INDIA / 24 - 28 SEPTEMBER 2012
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The effect of grinding mode on the efficiency of mineral separation (for pyrite and non-pyritic minerals from coal) has been investigated (Liu et al, 1993). It has reported that for
