Study On Preparation,structure And Performance Of Quartzose Jade Tailings Glass-ceramics

In recent years,with the exploitation and utilization of large-scale quartzose jade mines in China,large numbers of quartzose jade tailings have emerged.Quartzose jade tailings belongs to Al-Si solid waste,which contains a large number of main raw materials for preparing glass-ceramics such as SiO₂,MgO,Al₂O₃,and CaO.At the same time,it also contains a small amount of heavy metals such as Fe,Mn,which will endanger the safety of the environment.At present,the preparation of glass-ceramics using quartz-based jade tailings as the main raw material has not been carried out.In addition,at present,there are two major methods for preparing solid wastes,namely melting and sintering,but all of them need to be subjected to a high-temperature melting stage,resulting in greater energy consumption,and no method for directly sintering without high-temperature melting step is currently studied.Therefore,the feasibility of preparing glass-ceramics by different methods such as melting method,sintering method and pretreatment-sintering method is studied in this paper.XRD,fluorescence analysis,Raman analysis,DSC analysis,FESEM and other test methods were used to study the thermal properties,chemical composition and phase composition of quartzose tailings glass-ceramics.The appropriate dosage and heat treatment system for quartzose tailings in the preparation of glass-ceramics using different methods are clarified;the influence of changing the pre-treatment system on the sintering activity of quartz-based jade tailings raw materials is studied,and the micron quartz tailings micro-emulsion is studied.Research shows:1)When using quartz hematite as the main raw material,adding MgO and Na₂O to adjust the composition,and using TiO₂ and ZrO₂ as nucleating agents,the MAS system glass-ceramics with cordierite as the main crystalline phase can be prepared by the melting method.MAS glass-ceramics.Under the heat treatment conditions of800?/2 h and 1160?/2 h,the content of cordierite in glass-ceramics increases with the increase of the content of quartz jade tailings.The microstructure of the glass-ceramics exhibits long columnar crystals of 1-2?m in size.The suitable content of quartz jade tailings is 10 wt%-50 wt%,and the performance of glass-ceramics reaches the optimum value at 20 wt%,density 2.73 g/cm³,acid and alkali chemical stability 0.1%,Vickers hardness up to 885.2 Hv.2)Quartz-based jade tailings and CRT waste glass can be sintered to prepare CMAS-based glass-ceramics with feldspar crystals as the main crystalline phase.The suitable sintering system for glass-ceramics is:1100?/4 h.At the suitable sintering temperature,as the content of waste glass of CRT increases,the main crystallizing phase of the glass-ceramics is transformed from the anorthite to the sanidine.When the addition of CRT glass is 20 wt%,part of the granular pyroxene crystalline phase is precipitated,the size is about 100 nm,and the feldspar-like crystals are needle-like and have a size of 3-4?m.At the same time,the physicochemical properties of glass-ceramics reach the best value:2.62 g/cm³,the water absorption rate is 0.11%,and the chemical stability of acid and alkali resistance is 0.02%,which is better than natural marble,granite and other natural stone.3)Quartzose jade tailings were pretreated with different pretreatment processes,and CMAS glass-ceramics with the main crystalline phase of sanidine could be prepared by direct sintering with the pretreated tailings and CRT glass as the main raw materials.The use of HF solution as a pretreatment agent to pretreat the quartzite tailings can improve its sintering activity and crystallization ability.With the increase of HF concentration and pretreatment reaction time,the sintering activity of quartz jade tailings first increased and then decreased.With the increase of pretreatment temperature,the sintering activity of quartz jade tailings decreased.The best pretreatment process is:25?,8%HF,2-4 h,and the physicochemical properties of the glass-ceramics prepared under this regime are similar to those of the traditional sintered glass-ceramics.