The Properties And Research Of Pyrometallurgical Smelting Of Waste Automobile Exhaust Catalyst Slag

In this paper,aiming at the main components of the catalyst of waste automobile tail gas,the slag viscosity and melting temperature of the catalyst of waste automobile tail gas were accurately tested by using the RTW-10 melt physical property comprehensive measuring instrument.The composition range of molten slag is Al2O3:10%-15%,CaO/SiO2:0.7-1.1,MgO:6%;Focus on exploring the law of slag viscosity,melting temperature,degree of vitrification with CaO/SiO2,slag viscosity,melting temperature,and degree of vitrification with A12O3 content.And on this basis,further study the influence of different contents of B2O3 and Na2O on the viscosity,melting temperature and degree of vitrification of molten slag.,Based on the above research results,the composition of several groups of slag was determined,and the reduction smelting experiment and toxic leaching experiment were carried out to investigate the influence of slag composition of different components on the collection rate of platinum group metals in the catalyst of waste automobile tail gas,as well as the heavy metal leaching of smelted vitrified slag.According to the principles of low melting temperature,low viscosity,high metal collecting efficiency,easy separation of slag and gold,and strong vitrification of slag,the composition of slag components suitable for pyrometallurgical smelting of waste automobile tail gas catalyst was finally determined.The experimental results show that:For CaO-SiO2-Al2O3-MgO quaternary slag system,the viscosity of slag decreases with the increase of temperature.When the content of Al2O3 and MgO is fixed,the slag viscosity decreases first and then increases with the increase of CaO/SiO2 when the content of Al2O3 is 10%.When the content of Al2O3>is 10%,the slag viscosity decreases gradually with the increase of CaO/SiO2.The melting temperature of slag decreases first and then increases,and the glass degree of slag becomes worse and worse.The crystallinity is getting better;When MgO content and CaO/SiO2 are fixed,the slag viscosity decreases first and then increases with the increase of Al2O3 content.When CaO/SiO2=0.8,the melting temperature of slag increases continuously with the increase of Al2O3 content.When CaO/SiO2>0.8,the melting temperature of slag increases first and then decreases.The glass degree of slag becomes worse and worse with the increase of Al2O3 content.Na2O and B2O3 are commonly used slag viscosity reducers.According to the previous research results,the basic composition of slag is determined to be 46.67wt%SiO2-37.33wt%CaO-10wt%Al2O3-6wt%MgO.The influence of adding different amounts of Na2O and B2O3 on slag properties is explored,and the following conclusions are reached:With the increase of Na2O content,the slag viscosity decreases at first and then increases,the melting temperature increases at first and then decreases,and the glass degree becomes worse at first and then improves gradually.With the increase of the content of B2O3,the slag viscosity increases firstly and then decreases,the melting temperature of slag decreases continuously,and the glass degree of slag is good.With the increase of Na2O+NNa2B4O7 content,the slag viscosity firstly increases and then decreases,and the melting temperature continuously decreases.The glass transition degree of the slag is good.Based on the comprehensive research results,it was determined that 46.67wt%SiO2-37.33wt%CaO-10wt%Al2O3-6wt%MgO,45.74wt%SiO2-36.58wt%CaO-9.80wt%Al2O3-5.88wt%MgO-6.00wt%B2O3,The slag of 41.07wt%SiO2-32.85wt%CaO-8.80wt%Al2O3-5.28wt%MgO-6.00wt%Na2B4O7-6.00wt%Na2O was used for smelting test and toxic leaching test.It is found that under the same melting temperature and time,the collecting rate of PGMs is related to the melting point and melting temperature of the slag.The lower the melting point and melting temperature of the slag,the higher the collecting rate of PGMs.The leaching rate of heavy metals in the slag after leaching solution treatment is related to the glass degree of the slag,the better the glass degree of the slag,the lower the leaching rate of heavy metals in the slag.According to the above research,the reasonable melting slag type of the catalyst for smelting waste automobile tail gas is finally selectedCaO-SiO2-Al2O3-MgO-B2O3 five-element slag system,its basic composition:CaO/SiO2=0.8,36.58%CaO,45.74%SiO2,9.80%A12O3,5.88%MgO,6.00%B2O3.The results of this study can solve the problems of low capture rate of PGM,incomplete separation of slag and gold,and environmental pollution caused by catalyst of waste automobile exhaust,and have practical guiding significance for effectively reducing industrial production cost and increasing economic benefits.