Basic Research On The Preparation Of High-calcium Glass-ceramics From Yellow Phosphorus Furnace Slag

As industrial waste slag,yellow phosphorus slag is produced by the electric furnace method during the production of yellow phosphorus.With the rapid development of the yellow phosphorus industry,the discharge of yellow phosphorus slag has increased rapidly.At present,the resource utilization of yellow phosphorus slag is gradually biased towards building materials,i.e.cement,bricks,roadbed materials,etc.However,most products have low added value and low utilization rates of solid waste.Among them,the glass-ceramics prepared with yellow phosphorus slag as raw materials have high added value and excellent comprehensive performance and are widely used in the chemical industry,building materials,military industry,machinery,and other areas.In recent years,the research on yellow phosphorus slag glass-ceramics has gained wide attention in China.However,the chemical composition and content of the yellow phosphorus slag itself are different,and a large amount of minerals need to be added to adjust the basic glass components and melted at high temperature to prepare glass-ceramics.Which increases production energy consumption and cost,and further limiting the use of the high added value of yellow phosphorus slag.Based on the problems above,this paper studied the preparation process of yellow phosphorus slag high-calcium glass-ceramics,and explored the influence of the content of crystal nucleating agent on the properties.The preparation of yellow phosphorus slag and different pretreatment coal gangue high-calcium glass-ceramics was studied,and the effect of the heat treatment system on the properties of high-calcium glass-ceramics was studied by designing orthogonal experiments.In addition,on the basis of the research work above,deironed coal gangue was selected as the flux to replace silica.The acidity value was adjusted before the simulation study conducting in a high-frequency furnace with reference to the actual production system.Without affecting the yield of yellow phosphorus,the composition of the residue is designed to be close to that of the basic glass.Using molten slag as the basic glass,the high-calcium glass-ceramics are prepared by direct heat treatment.Focus on studying the effect of nucleation temperature on the structure and properties of high calcium glass-ceramics.In this paper,yellow phosphorus slag is used as the main raw material,and analytically pure Si O₂,Al₂O₃,Mg O,Ti O₂,and other substances are added to prepare the high-calcium glass-ceramics by melting method.The feasibility of preparing high-calcium glass-ceramics with yellow phosphorus slag was verified.Different pretreatment coal gangue was added and melt to prepare high-calcium glass-ceramics.An orthogonal test was designed to study the effect of the heat treatment system on the properties of high-calcium glass-ceramics.The results indicated that the high-calcium glass-ceramics with deironed coal gangue showed the best comprehensive performance.The main order of the influence of heat treatment system factors on the glass-ceramics is as follows:crystallization temperature>nucleation temperature>nucleation time>crystallization time.The optimal heat treatment system is nucleation temperature 740^oC,nucleation time 3 h,crystallization temperature 910^oC,and crystallization time 2 h.Under these conditions,the compressive strength of glass-ceramics is 766.30 MPa,bulk density is 2.87 g/cm³,and the acidic mass loss rate is 0.1%,the basic mass loss rate is 0.01%,the expansion rate is 3.73%,and the water absorption rate is 0.05%.With reference to the actual production system,a simulation study was conducted in a high-frequency furnace to prepare high-calcium glass-ceramics directly from the molten slag.The results showed that at the reaction temperature of 1400^oC,the acidity value of 1.0,the carbon excess coefficient of 1.02,and the reaction time of 1 h,the phosphorus conversion rate of the system is 93.99%.The glass-ceramics showed better comprehensive performance with the nucleation temperature of 770^oC,the nucleation time of 3 h,the crystallization temperature of 940^oC and the crystallization time of 2h.