Chemical Enhancement to Magnetic Separation in Kaolin Beneficiation
The value creation with kaolin clays depends on removing the colored impurities which manifests in to higher brightness-one of the most sought after properties on applications such as paper coating, paint and others. The processes for removing impurities include magnetic separation, froth flotation and selective flocculation. While the flotation and selective flocculation processes exploit the physico-chemical differences between the surface properties, the magnetic separation uses the bulk magnetic susceptibility differences between the diamagnetic clay and ferro- and para-magnetic nature of the impurities. The major advantage with magnetic separation remains high yield and no or low reagent usage. However, the magnetic separation technology suffers from low separation efficacy when finer colored impurities (＜1 μm) are encountered in the feed. Use of stronger magnetic intensities during magnetic separation showed limited success; nonetheless the adverse effect due to finer size range remains a dominant effect even at 5 Tesla magnetic field. Furthermore, the presence of diamagnetic colored impurities irrespective of their sizes can not be removed.Cytec Industries has recently developed a bolt-on chemical enhancement technology for magnetic separation that essentially embraces the best product performance attributes of flotation and selective flocculation while keeping the chemical usage to a minimum level and using the readily available magnetic separation equipment. The paper will outline the technology and illustrate optimization work at pilot plant magnet on a wide variety of crude accommodating the process needs and plant limitations. The major advantages of chemical enhancement technology to magnetic separation include: 1) simple extension to existing magnetic separation technology, 2) ability to produce comparable product in quality with cost effectiveness compared to flotation and selective flocculation, 3) removal of impurity minerals over wide size range, 4) removing non-magnetic impurities,5) providing robust process with high process yield and 6) operation-friendly nature. Furthermore,chemical enhancement technology for magnetic separation has also emerged as a platform for removing impurities at low levels in other mineral systems as well.
Magnetic Separation Chemical enhancement Kaolin Beneficiation Brightness Coloured impurities Separation
S.A. Ravishankar A. Gorken J. Villegas
Cytec Industries Inc., Stamford
国际会议
XXIV International Mineral Processing Congress(第24届国际矿物加工大会)
北京
英文
702-710
2008-09-24（万方平台首次上网日期，不代表论文的发表时间）