Experimental Study On The Preparation Of Silicon Crystal Composites Using Iron Tailings And Blast Furnace Slag

With the rapid development of China’s steel industry,a large number of mines have been mined,and the stockpiling of iron tailings has been increasing.At the same time,the steel output increased,and the blast furnace slag discharge also increased.These bulk metallurgical solid wastes are putting increasing pressure on the ecological environment,and green recycling of bulk metallurgical solid waste such as iron tailings and blast furnace slag has become a research hotspot.In this paper,silicon crystal composites were prepared by iron tailings and blast furnace slag.On the existing basis in the laboratory we use iron tailings and blast furnace slag to prepare foamed ceramic materials,and the bulk density,thermal conductivity,compressive strength and water absorption of the prepared samples were tested.Pyroxene glass ceramics with three different crystal structures were prepared by iron tailings,blast furnace slag and auxiliary materials magnesium oxide,alumina and sodium carbonate in differential thermal analysis and X-ray diffraction and other auxiliary measurement methods.The density,hardness and water absorption of the samples were tested.At the same time,the microstructure of the samples under the optimal process was analyzed by SEM.On the basis silicon crystal composites were prepared with foamed ceramic materials and pyroxene glass ceramics.The foamed ceramic materials with certain strength were prepared by adjusting the ratio of iron tailings and blast furnace slag based on the research of the existing technology and additives such as foaming agent in the laboratory When the ratio of iron tailings to blast furnace slag is 6:4,the sample performance is the best.The bulk density of the sample is 0.212g·cm-3,the thermal conductivity is 0.077W/(m·K),the compressive strength is 0.85MPa,and the water absorption is 0.42%.Pyroxene glass ceramics samples were prepared from iron tailings and blast furnace slag,and three pyroxene glass ceramics with different crystal structures were prepared with 8%MgO.At 840℃,it is[(CaMg0.75Fe0.25)Si2O6],at 900℃,it is[Ca(Mg0.7Al0.3)(Si1.7Al0.3)O6],at 940℃,we get another crystal structures,it is[(Ca0.818Mg0.792Fe0.183Fe0.086Al0.151Al0.269Si1.751)O6].The results show that the sample has the best properties when the nucleation temperature is 840℃,900℃ and 940℃,the nucleation time is 75 minutes,the crystallization temperature is 1200℃,and the crystallization time is 60 minutes.The sample density was respectively 2.68g·cm-3,2.78g·cm-3 and 2.73g·cm-3,the hardness was 150.32MPa,164.33MPa and 145.86MPa,,and the water absorption was 0.1%.The nucleation temperature is 840℃,the crystal shape is hollow flat hexagonal prism,the crystal length is 4～6μm,the degree of crystal aggregation is relatively high,and the glass phase is relatively small.The nucleation temperature is 900℃ the crystal shape is long rod type,the crystal length is about 20 microns,the crystal diameter and distribution are relatively uniform,there are many glass phases,the nucleation temperature is 940℃,the crystal shape is hollow short film,the crystal length is 2～10 microns,the crystal aggregation degree is high,and the content of glass phase is low.In addition,the growth mode of crystal should be layering and superposition.The silicon crystal composites are prepared with obtained microcrystalline glass and foamed ceramics,and the tensile strength of the silicon crystal composite with different crystal structure was studied.It was found that the silicon crystal composite with nucleation temperature of 840℃ and the sample at nucleation temperature of 940℃could meet the requirements,and the product performance was the best with nucleation temperature of 840℃,the tensile strength of the sample was 0.41 MPa,and the distance from the sintering point was 2.3cm.