CFB Zhungeer Coal Power Plant Ash Metallurgical Grade Alumina Extraction Process Research

The burning technique of circulating fluidized bed(CFB)is a new technique, which have the advantages of wide adaptability of fuel,high rate of burning,low quantity of NO_x senting out,wide load adjust.With the developing of electric power,the burning technique of CFB will become the main burning technique.At the same time,it will bring the new solid waste,circulating fluidized bed ash.At present,there are a few of reports about comprehensive utilization of circulating fluidized bed ash,especiallly,there is not high technique or high income research. In this paper,in allusion to the comprehensive utilization of circulating fluidized bed ash,we try to find a route of reasonable utilizationThe components,structures and properties of circulating fluidized bed ash have been investigated by XRD,laser granularity apparatus and rapid analysis instrument of silicate.The analysis results show that the CaO,SO₃ and burning loss were large for middle temperature burning and adding of limestone as desulfrize reagentat the time of burning,there were no mullite,and the Al and Si were active. For its characteristics,this paper presents a acid-the base of fly ash from fluidized bed extraction metallurgical grade alumina production processes.Entire experiment is divided into acid-soluble,concentrated crystallization, calcined,alkali-soluble,and then calcined Seed six parts.â‘ acid-soluble aluminum dissolution rate is an important indicator of part of the experiment,which will affect the final product yield,based on past research findings,impact on the rate of acid-soluble ash CFB the principal factors that have temperature,time and acid than ash.Able to associate CFB power plant ash waste as raw materials in the laboratory within the temperature,time and the acid ash than the rate of alumina dissolution test.The results showed that in the CFB gray aluminum dissolution rates increased with temperature increases.However,as the use of laboratory containers for the general dissolution of the glass bottles,not under pressure,and high temperature would lead to serious hydrochloride volatile,so small experimental test the response of the temperature controlled at 95℃within.CFB time on the acid-soluble aluminum gray in the dissolution rate of the acid-soluble time with the increase in dissolution rate also increased in the more than two hours after the time the increase of acid-soluble dissolution rate change has slowed down, and considering the cost factor,the reaction in time to control within two hours. CFB acid gray ash than in the aluminum dissolution rates of the fundamental changes little.This is due to CFB alumina contained in the ash different degrees of activity,increased activity in the good part of the acid dissolution can be sustained, even if the activity of the alumina increased less acid,we can not fully respond. Therefore acid ash than in the control 2.3 can be.CFB ash on the dissolution of the test were to be quasi-rock,ash in the CFB 850℃,950℃,1050℃,1150℃and 1250℃under the roasting conditions,the acid-soluble calcined samples.Grey fixed ratio 2:1 acid,acid temperature 95℃,acid 2 hours.Based on the reaction of alumina content and different temperature roasting CFB XRD patterns of gray,IR spectrum analysis in the acid-soluble ash obtained CFB demonstrated in the course of the activity and its high alumina calcination temperature,850℃Forging burning conditions can be higher dissolution rate of aluminum,more than 850℃aluminum activity will be reduced,when the temperature reached 12.5℃,the Central Plains CFB ash some quality kaolin meet changing nature of the stability of mullite,Al-O bond and the Al-O-Si bond activity will be reduced,leading to the dissolution aluminum.â‘¡some of the major concentration is the crystallization of continuous acid-soluble liquid residue after separation after the chloride concentration Qingshi into the tank enrichment crystallization.Concentrator for the enamel pot,ohmic heating.In order to speed up the pace of concentration crystallization using vacuum concentration.Add the condensed liquor buffer cooling tanks,with the temperature drop,crystal aluminum chloride crystal from the beginning,can be filtered crystalline aluminum chloride.Concentrated crystallization conditions:temperature 85 to concentrate 110℃,the vacuum suction 0～-0.06 MPa.â‘¢crystalline aluminum chloride burning part of its focus is to determine the complete decomposition of the calcination temperature and the decomposition of hydrogen chloride gas recovery and utilization.Through the examination of crystalline aluminum chloride samples TG-DTA curves of aluminum chloride that crystallization temperature increases gradually with the loss of water,all of the final decomposition of hydrogen chloride gas and produce alumina.In order to determine the crystalline aluminum chloride complete decomposition temperature,we had a different temperature burning test, calcination time for two hours.By analyzing different calcination temperature map of the X-ray crystal aluminum chloride in the calcination temperature of 360 to 600℃,calcination time in a static state for 2 h.â‘£alkali dissolution experiments through from Bayer alkali concentration on the basis of our study focused on the temperature on the rough dissolution rate of alumina,the temperature accordingly alkali-soluble At the same time,the composition of the red mud has done and Phase a focus on.Bayer reference to the dissolution of bauxite alkali conditions, only rough conditions for the dissolution of alumina alkali lye Na2O content concentration of 165g/L,the amount of alumina rough 170g/L,molecular ratio of 1.6,dissolution temperature 210～240℃,the dissolution time is 2 h.Based on the chemical composition of red mud and spirits of alumina in the rough that the process of alkali-soluble Fe2O3 as insoluble exist in red mud,and CaO in the process of alkali-soluble and insoluble alumina from a combination of hydrated calcium aluminate.⑤process is the kind of rough-alumina after the reaction of alkali solution of sodium aluminate solution cooling,making it a supersaturated solution,in this over-saturated solution of aluminum hydroxide added to seed, continuous mixing,a decomposition of sodium aluminate,generated aluminum hydroxide precipitation.Through the kind of aluminum hydroxide at the X-ray diffraction pattems and infrared spectra of the crystal analysis of decomposition conditions:Solution for Al2O3 content concentration 170g/L;seed coefficient of 1.5(390g aluminum hydroxide/L)at the beginning of before temperature is 75℃to terminate 35℃;Seed Time:50 h.â‘¥aluminum hydroxide will be part of calcined alumina in the high temperature hydrogen from water adsorbing water and structure,and make it crystal changes in the system of metallurgical grade alumina process.Seed will be the aluminum hydroxide in 1000℃,1100℃and 1200℃under calcination temperature conditions.Through the different samples calcined under the conditions of temperature X-ray diffraction and infrared spectra of Fig. We can see that the 1200℃calcined alumina for the crystallization of a well-Al2O3.Bayer has been with the alumina production process,we have identified hydrogen alumina calcination temperature for 1200℃,calcined for 2 h, in this temperature will be sub-species of hydrogen to a number of calcined alumina test finally GB with the goods to one of the two standards for metallurgical grade alumina products.In conclusion,this study analyzed the characteristics of fly ash CFB proposed acid-the base of fly ash from fluidized bed extraction of a metallurgical grade alumina production process.And the process conditions,product performance to a more in-depth study and discussion,as an important way to provide comprehensive utilization of fly ash...