热处理温度对磷渣-煤矸石微晶玻璃结构和性能的影响

The effects of heat treatment temperature on performance and structure of phosphorus slag-coal gangue glass-ceramics

以磷渣和煤矸石为原料,采用一步烧结法制备了性能优良的CaO-Al_2O_3-SiO_2(CAS)系微晶玻璃,用差示扫描量热法(DSC),X射线衍射(XRD)和扫描电子显微镜(SEM)等对其进行分析和表征,研究了热处理温度对微晶玻璃晶相组成、微观结构和宏观性能的影响规律。结果表明,固废利用率达100%,微晶玻璃性能良好;以磷渣和煤矸石为原料在1250℃下熔融2 h、于850℃热处理保温2 h可制备主晶相为假硅灰石Ca_3(Si_3O_9)的微晶玻璃,其抗折强度、显微硬度和体积密度分别为74.4 MPa,566.9HV和2.75 g/cm3。随热处理温度升高,微晶玻璃主晶相由Ca_3(Si_3O_9)相转变为硅灰石CaSiO_3相,晶体形态由球状向针状、短柱状改变,对提高微晶玻璃抗折性能有利,而显微硬度和体积密度均先增加后降低。

Phosphorus slag is an industrial waste produced in the production of yellow phosphorus by the electric furnace method.For each 1 t of yellow phosphorus produced,it is necessary to discharge 8~10 t of phosphorus slag.Coal gangue is a solid waste produced in the coal industry.It is discharged from 10%to 15%of annual coal production.It has accumulated more than 4.5 billion tons of storage,which is the largest solid waste in China.Since a large amount of unexploited solid waste occupied industrial and agricultural land,safety problems andenvironmental pressures are presented.The disposal of solid waste is an urgent task.Therefore,the effective use of the solid waste resources and turning waste into treasure have important practical significance.In recent years,the glass-ceramics based on solid waste has been widely used in building decoration field.However,the technology has not been widely used due to high cost and defects in the preparation process.In this work,the feasibility of preparing glass-ceramics by the combination of phosphorus slag and coal gangue was studied.The effects of heat treatment temperature on the crystalline phase composition,microstructure and properties of the glass-ceramics were also discussed via differential scanning calorimetry(DSC),X-ray diffraction(XRD)and scanning electron microscopy(SEM).Powder base glass was obtained by melting phosphorus slag with coal gangue at 1 250℃for 2 h.The results indicated that the sintered glass-ceramics with pseudo wollastonite Ca3(Si3 O9)as the main crystallization phase could be prepared after heat treatment at 850℃for 2 h.The flexural strength,microscopic strength and bulk density of the sample were 74.4 MPa,566.9 HV and 2.75 g/cm3,respectively.In addition,with the increase of heat treatment temperature,the main crystalline phase of the glass-ceramics changed from Ca3(Si3 O9)to wollastonite(CaSiO3),the morphology of the crystal developed from spherical to the needle-like and short column,which were beneficial for improving the flexural strength.Both the microscopic strength and bulk density increased first and then decreased with the increase of heat treatment temperature.