• Mineral and Industry
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• v.26
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• pp.13-21
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• 2013

This study is carried out experiments on various factors for improving the grade of low grade scheelite by Knelson concentrator prior to the main beneficiation process. Even though there are several gravity separators such as Jig, Spirals and etc. for rougher concentrate, the KC3 Knelson Concentrator was adopted to get better separation efficiency and beneficiating effects for pre-concentration of the low grade scheelite ore. The feed samples was prepared to minus 1mm in size by crushing and grinding. The important factors in the KC3 Knelson Concentrator test were examined in terms of the variations such as number of treatment, feed rate, rotation speed of bowl(G force), water flow rate, pre-removal of magnetic minerals, feed size and feed grade. According to the result of experiment, it shows that the important technical variations are limited in terms of number of treatment, feed rate, feed size and feed grade. The final result shows that the KC3 Knelson Concentrator obtains the scheelite pre-concentrate of about $3%WO_3$ grade and 90% recovery, respectively, from the feed containing about $0.8-1.0%WO_3$ grade.

• Resources Recycling
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• v.25 no.1
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• pp.24-30
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• 2016

The study to obtain tantalum concentration from electronic components (ECs) on Printed circuit board assembly (PCBA) of laptop was conducted. Electronic components on laptop PCBA were detached from boards by using self-developed experimental apparatus. The detached electronic components were sieved and 93.2 wt.% of tantalum capacitors were concentrated from the size interval from 2.80 mm to 6.35 mm. The tantalum capacitors were pulverized by hammer mill and electrodes (anode and cathode) were removed from the grinding products by using magnetic separators under the magnetic force of 300 Gauss. Finally, tantalum concentrate was concentrated from the magnetic separator products by using Knelson concentrator, and the maximum efficiency of 76.9% was achieved under the operating condition of bowl rotating speed of 200 rpm, and fluidizing water flowrate of 7 L/min. The grade and recovery of Ta concentrate under the condition were 81.1% and 78.8%, respectively.