Document Details
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Document Type |
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Project |
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Document Title |
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Production of Sodium Aluminate From Local Clays انتاج الومينات الصوديوم من خامات الطفله السعوديه |
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Subject |
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Chemical and Materials Engineering Department |
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Document Language |
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Arabic |
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Abstract |
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Sodium aluminate is not produced locally in the Kingdom. It is imported to satisfy local industry requirements and for other applications. The principal source for manufacture of sodium aluminate is bauxite ore, a mineral containing about 40-60% alumina and less than 7% silica. Limited reserves of bauxite have been discovered in the Kingdom's land.
This study was carried out to investigate the possible manufacture of sodium aluminate to satisfy local demands from local Saudi clays that are extremely abundant in the Kingdom' land, rather from the much scarcer bauxite, using the lime sinter process. Local kaolinitic clay containing 29.4% Al2O3 was activated by calcination at 700oC for one hour, the activated clay was then sintered with calcium carbonate, followed by leaching the sintered mass with sodium carbonate solution to solubilize alumina in the clay as sodium aluminate.
In the sintering step, the effect of the following parameters on alumina extraction was investigated, sintering temperature, from 1200 - 1400oC , duration of sintering, from 0.5 - 3.0 hour, and mole ratio of CaO / Al2O3 + SiO2, from 2.5 - 4.0, and fixed leaching conditions of 70oC, 0.5 hour and 2.2 for temperature, period of leaching and Na2O / Al2O3 mole ratio respectively. The results obtained from the bench scale experiments indicate an increase in alumina extraction at a temperature range of 1250 – 1350oC, followed by a decrease with increasing temperature to 1400oC. The effect of period of sintering on alumina extraction from local clay is found to depend on both sintering temperature and the mole ratio CaO / Al2O3 SiO2 used. The results obtained indicate that as the mole ratio CaO / Al2O3 + SiO2 increases , the recovery of alumina from local clay increases up to a sintering temperature of 1300oC. This effect is more pronounced by increasing both temperature and period of sintering. The recommended conditions for the sintering step are: 1350oC, one hour and 2.5 for sintering temperature, sintering period and CaO / Al2O3 + SiO2 mole ratio, respectively. The percent alumina extraction under these conditions is 48.32.
The results obtained from the leaching step indicate relatively slight effect for increasing leaching temperature, leaching period and Na2O / Al2O3 mole ratio on alumina extraction. The maximum alumina extraction from local clay achieved is 55% at leaching conditions of 90oC, 3.0 hour, and 3.0 for leaching temperatures, leaching period and Na2O / Al2O3 mole ratio, respectively. These relatively low results suggest evaluation of other processes such as the lime-soda sinter process for production of sodium aluminate from local clay rather than the lime sinter process. |
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Publishing Year |
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1425 AH
2005 AD |
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Added Date |
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Saturday, November 7, 2009 |
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Researchers
| عبدالرحيم أحمد الزهراني | Al-Zahrani, AbdulRahim Ahmad | Investigator | Doctorate | |
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