Evaluation and processing of andalusite mineral from Terengganu, Malaysia
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Date
2015-11-01
Authors
Seng Sophea
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Abstract
In this research, two andalusite bearing rock samples from Sungai Cerul and Kemasik, Terengganu areas were studied. Coarse andalusite crystals in range of 2 cm to 5 cm in length were found embedded or cemented with phyllite in sample from Sungai Cerul. Whereas, the presence of andalusite crystal in the andalusite bearing rock sample from Kemasik was hardly to be observed. Grade of andalusite bearing rocks from Sungai Cerul indicated that it is contain approximately 49.13% Al2SiO5 and analysis on the andalusite crystal found that it contains up to 73.35% Al2SiO5. Due to the high percentage of andalusite, this deposit has the potential to be exploited for its value. The samples from Kemasik occurred in similar geological environment as in Sungai Cerul which is disseminated in phyllite as host rock. Though, the occurrence of andalusite mineral in Kemasik was affected by high weathering and alteration. Compared to samples from Sungai Cerul, the andalusite bearing rock from Kemasik have no specific andalusite crystal shape in host rock and the grade of Al2SiO5 is about 40.81% Al2SiO5. Due to the physical properties of andalusite from Kemasik is comparatively difficult to be processed by physical methods this deposit was considered not viable for the time being. The experimental works on grinding performance on andalusite bearing rock from Sungai Cerul indicated that the optimum rotational speed of the rod mill to liberate the andalusite mineral from the host rock is at 20 rpm for 40 minutes. The liberation and separation of andalusite from the host rock managed to improve the grade of andalusite approximately 13.14 % Al2SiO5. With the microwave treatment, the liberation has been improved and increased the grade of andalusite up to 17.44 % Al2SiO5. Grinding time was also reduced from 45 minutes to 15 minutes with better liberation from 60% to 70% when microwave treatment was applied. In addition, the microwave treatment with low temperature in wet condition show a good result of the breaking the andalusite crystal interface.