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Pilot Plant Test Of Decompositing Aluminium Sulfate Into Aluminia

Posted on:2009-06-18Degree:MasterType:Thesis
Country:ChinaCandidate:R Q WangFull Text:PDF
GTID:2131360308979716Subject:Metallurgical physical chemistry
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The project extracts alumina by sulfuric acid from coal fly ash, the surplus silicon dioxide were made into white carbon black. So that the project can realize the use which is uncontaminated and have additional value. This paper did research on the technological process of making aluminium sulfate solution into metallurgy level alumina, in order to do service to get through the technological process of extracting alumina from coal fly ash.1. Worked out the technological process of preparing alumina from aluminium sulfate solution:aluminium sulfate solution→evaporation concentration→crystallization→dehydration→decomposition→alumina.2. Did laboratory studies on every process of this technological process. The main conclusions are drawn as follows:1) Did experiments on aluminium sulfate solution at atmospheric pressure and reduced pressure, and obtained technological parameters of them. Boiling temperature of aluminium sulfate solution at atmospheric pressure is 115-117℃, which is 90℃at reduced pressure, the negative pressure is 0.052MPa.2) After evaporation and concentration, cool aluminium sulfate solution to crystallization, and the crystal is Al2(SO4)3·18H2O. Retain the surplus solution to the concentration process to concentrate again.3) Studied the technology of dehydration of aluminium sulfate crystal. Did researches on the effect that temperature, time and adding aluminium sulfate powder do to the dehydration; studied the dehydration situation of aluminium sulfate solution after concentration under different time and temperature. Determine that the material is aluminium sulfate crystal, which is dehydrated directly under high temperature. The dehydration temperature is 350℃, dehydration time is 1.5 hours.4) This paper intends to prepareγ-Al2O3, so control the highest experimental temperature at 900℃, did researches on the effect of temperature and time do to the decomposition of aluminium sulfate into alumina separately, studied the formation amount of SO3 and SO2 at different temperature. Determined that the calcination temperature is 800℃, and the calcinations time is 2.5 hours. Under conditions above, most of the formation gas is SO3.3. Selected equipments for every process of the technological process above.4. Arranged the pilot plant, gave the layout plan and the equipment connection graph.5. Determine the process condition and throughput of every process of pilot test, with which did pilot tests. Then did analysis and detections to the products of the pilot test. Product alumina accords with national standard.6. Did economic benefit analysis of the process, contains material balance and energy balance.7. This process realizes the cyclic utilization of water and sulfuric acid. The waste gas released such as SO3 can meet the exhaust emission standard after treatment. Did environmental assessment to this project, there is no waste material generated, and is friendly to environment.
Keywords/Search Tags:coal fly ash, aluminium sulfate, alumina, concentration, crystallization, dehydration, decomposition, pilot test
PDF Full Text Request
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