Research On Extraction Process Of Rare Rarth From Fly Ash In Guohua Jungar Power Plant

Twenty-first Century is an era in which rare earth elements are widely used in high and new technology,rare earth metals and their oxides have been widely used in many fields such as petroleum industry,photoelectric technology,chemical industry,metallurgy,textile,ceramics,glass,permanent magnet material and so on.With the progress of science and technology and application technology,the value of rare earth metal and its oxide will be more and more important.The United States,Japan and EU countries have listed REE as the national strategic resources of rare earth.Rare earth has risen to the national strategic resources.Therefore,the extraction of rare earth from fly ash can be regarded as a kind of technical reserve for the national strategy.At the same time,the extraction of REE from fly ash can also increase the added value of fly ash comprehensive utilization.In this study,the fly ash of Guohua Jungar power plant is taken as the research object.The content of alumina in the fly ash reached 40.5% and the molar ratio of aluminum to silicon was 1.18 by XRF.The main minerals in the fly ash are quartz,mullite,calcite and gismondine by XRD.The phase morphology of the fly ash was observed by SEM-EDS.It was found that the fly ash was irregular in shape,loose in surface,less typical in glass beads,and precipitated in aluminosilicate with crystal structure.Single factor and orthogonal experiments were used to optimize the leaching process of rare earth elements in fly ash.The best scheme for Leaching Rare Earth from fly ash was put forward in order to improve the leaching rate of rare earth elements,low cost and no pollution.Leaching condition: 1mol/L hydrochloric acid,the temperature is 40?,the solid-liquid ratio is 1:10,time is 2h.The process of removing impurity from acid leaching liquor was studied.First,the extract was evaporated and concentrated to 1/5,filter,washing precipitation,precipitation is mainly silicic acid and its adsorption chloride.The filter fluid is then evaporated and concentrated to 1/2,REE enrichment solution was obtained by filtration.Washing precipitation,precipitation is calcium sulfate.The best process for precipitation of rare earth: The mixture of oxalic acid acetone solution and REE enrichment liquid is mixed according to a certain proportion,heat the mixture until it is slightly boiling,the pH value is adjusted to 1.5-2 by a certain concentration of ammonia water.Keep the temperature above 70-80 for more ?than 1 hours.Cool down to room temperature,aged 30 min,filter with slow quantitative filter paper,transfer the precipitation to the slow quantitative filter paper.Wash precipitation 8-10 times with a specific concentration of oxalic acid solution(adjust pH value 1.5-2 with ammonia water).The precipitation in the muffle furnace burning 850 ?after washing.Remove the precipitate and ground to the powder,then remove the calcium oxide with distilled water and then cook again.Finally,the mixed rare earth oxide with purity above 70% was obtained.The extraction of REE from fly ash by this method is simple operation,less material needed.The high added value of fly ash is fully realized.