| The gasification conditions of Shell gasifiers were relatively harsh,and it was currently impossible to observe the gasification state of coal particles in the gasifier all time.Therefore,this article analyzed the ash chemical and physical properties of industrial ash produced by multiple Shell gasifiers,to judge the operation of each gasification furnace,to provide a reference for optimizing the operating conditions of the gasification process;at the same time to analyzed the differences in other physical and chemical properties of the gasification slag,to provide a reference for solving the application problem of the gasification slag and achieving high-value utilization.The properties of the filter cake were modified by the froth flotation method,and the changes in the properties of the filter cake before and after the modification were compared and analyzed.Element analyzer,particle size analyzer,XRF,XRD,ash melting point tester,flotation machine,calorimeter,SEM-EDX,specific surface area tester,thermal analyzer and other instruments were used to test and analyze characterize the ash of gasification slag chemical properties,and physical and chemical properties.Alkali metals Ca and Fe were easy to accumulate and form low melting point minerals in the coarse slag,reducing the ash melting temperature of the coarse slag;the enrichment of Fe was related to the atmosphere and the content of other alkali metal elements;K,Na and Mg played a role in lowering the melting temperature of ash,but it was difficult to play a significant role because of it was low content.The ash melting temperature of the same series of ash(coarse slag,fly ash and filter cake)had a small difference,and the ash melting temperature was below 1350?.Under normal circumstances,the reaction of coarse slag and fly ash particles was relatively complete,and the carbon residue content was low,below 2%;the carbon residue content of the filter cake was relatively high,above 40%,and the reaction temperature was 100°C higher than that of raw coal.The average pore size of coarse slag,fly ash and filter cake was similar,about 3.8 nm.The filter cake contained a certain amount of wedge-shaped holes and crack-shaped holes,and there were many closed holes at one end in the fly ash and coarse slag.The specific surface area of coarse slag and fly ash was 2-4 ?/g,HZ had a higher carbon content,and the specific surface area was 8.391 ?/g;the specific surface area of filter cake was larger,greater than 16 ?/g,ALB-1 had the largest specific surface area,22.218 ?/g.The pore volume of coarse slag was generally smaller than that of fly ash,which was less than 0.02cc/g;the pore volume of filter cake was relatively large,about0.05cc/g.Coarse slag was mainly composed of particles with smooth surfaces and irregular shapes,with extremely low carbon residue content,and a small number of particles with relatively high carbon content on rough surfaces.The fly ash was composed of spherical particles and powder particles of different sizes.The surface of the spherical particles was attached with tiny particles,and the pores on the surface of the spherical particles were mostly semi-closed pores.The particle shape in the filter cake combines the characteristics of fly ash and coarse slag.It was composed of spherical particles and irregular particles,with a high carbon content.The residual carbon in the filter cake was separated by one-step flotation method.The flotation agent and residual carbon were physically combined to float to the liquid surface.The separation efficiency was above 60%.The improvement of the slurry potential can significantly improve the flotation efficiency and ash content of tailings.Figure 54 table 45 reference 89... |
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