Harmless Treatment And Comprehensive Utilization Of High Alkali Fly Ashes Produced By Burning Black Coal-water Slurry

High alkali fly ashes produced by burning black coal-water slurry is a solid waste with high alkalescence. It can cause persistent contamination to the surrounding environment. On the basis of summarizing many technologies and comprehensive methods of solid residues, a new harmless treatment of high alkali fly ashes with coal gangue or clay brick technology is presented in the paper firstly.Feasibility argumentation was made from the following three facts:1)The modeling calculation of chemical compositions and CIPW standard minerals of brick materials added high alkali fly ashes.2)After solidifying the alkali enters steady mineral phases.In experiments, a series of high alkali fly ash-coal gangue bricks used materials with different ratios of high alkali fly ashes added to coal gangue in the productive line of coal gangue brick. Then lixiviated toxicity and stabilization of alkali in the bricks were mensurated according to methods stated in national standards. Thirdly, XRD phase of bricks were analyzed to research the changing of phases in the process of sintering . At last, acid rain eluviate experiments were carried out and results showed that lixiviated toxicity of alkali and quality of brick were up to scratch. Some conclusions were drawn as following:1.The ashes produced by burning black coal-water slurry are high alkali(especially sodium).Its important to seek and develop harmless treatment and comprehensive utilization technology to high alkali fly ashes. Through argument, safety landfill disposal is the temporary treatment before better measurements were carried out. Adding high alkali fly ashes into building materials is a better available method of comprehensive utilization, that's sintering bricks with coal gangue and clay respectively added high alkali fly ashes.2.The optimum adding percentage of high alkali fly ashes is about 12% to coal gangue and 15% to clay. XRD test reveals that feldspar, pyroxene, spinelle are formed and high alkali fly ashes enter crystal lattice in the process of sintering bricks. So high alkali fly ashes is solidified well. So high alkali fly ashes are steady and can...