| Gold mine tailings are solid waste produced after gold ore is orely processed.With the expansion of the development scale of gold mines,the emissions of gold mine tailings are increasing year by year.A large number of gold mine tailings are deposited as solid waste in the tailings pond,which not only occupies a large amount of land,pollutes the surrounding environment,but also causes a series of safety and environmental protection problems.Today,with the one-time resources becoming increasingly exhausted,the comprehensive development and utilization of gold mine tailings as a resource has become one of the hot topics today.In this paper,gold mine tailings are used as the main material,and clay is used as auxiliary material to prepare sintered bricks,which are used as building materials.Firstly,the basic properties of gold mine tailings and clay are systematically analyzed.Then,the optimal firing parameters of gold ore tailings sintered bricks are determined by single factor test,and the sintering process and mechanism of gold mine tailings sintered bricks are studied.Based on the response surface method,the firing parameters of the gold ore tailings sintered bricks were optimized,and the tailings sintered bricks with good performance under the best conditions were obtained.The specific research content and achievements are as follows:(1)Study on the basic properties of gold mine tailings and clay.The composition and physical and mechanical properties of the gold mine tailings taken from the mine site were tested.It was found that the gold mine tailings have the characteristics of fine particles,good plasticity,low silicon and aluminum content,and high iron and calcium content.Adding an appropriate amount of clay to the gold mine tailings can effectively improve the conditions for the use of gold mine tailings as brick raw materials to meet the purpose of preparing sintered bricks from gold mine tailings.(2)Study on firing parameters of gold ore tailings sintered brick under single factor condition.The effects of the ratio of the two raw materials,the molding moisture,the sintering temperature and the holding time on the properties of the tailings sintered bricks were studied by single factor experiments.The test results show that the compressive strength,loss on ignition and bulk density of the sintered bricks increase with the increase of clay content,sintering time and holding time.The water absorption rate gradually decreases with the increase of clay content,sintering time and holding time.The water absorption,loss on ignition and bulk density of the sintered bricks gradually increase as the molding moisture increases.Through the single factor test,under the premise of using gold mine tailings as much as possible,the best firing parameters of the gold mine tailings sintered bricks are: gold mine tailings: clay(mass ratio)is 7:3,molding moisture 25 %,sintering temperature 1000 ° C,holding time 2 h.(3)Sintering process and mechanism analysis of gold ore tailings sintered brick.The sintering process and mechanism of tailings sintered bricks were studied by differential thermal analysis(TG-DTA)and X-ray diffraction analysis(XRD).The results of TG-DTA show that in the firing process of the sintered brick,the bound water,structural water and crystal water in the blank are discharged as the temperature increases.Part of the mineral lattice of the billet re-forms a new crystalline material.Comparing the XRD spectra of raw materials with that of tailings sintered bricks,it was found that the diopside,pyrite,montmorillonite and calcite in the raw materials were decomposed in the process of burning and formed new minerals,namely hematite and anorthite.The main minerals in the sintered brick are: quartz,albite,hematite and anorthite.(4)Experimental study on optimization of firing parameters of gold ore tailings sintered brick based on response surface methodology.Taking the compressive strength and water absorption of the sintered brick as the response value,the regression model of the compressive strength and water absorption of the gold mine tailings sintered brick was applied by the response surface method.The model was analyzed by significant analysis,variance analysis and response surface graph to verify the reliability of the model.The test results show that the regression model of compressive strength and water absorption of sintered gold bricks in gold mine tailings is better and has higher reliability.The optimal firing parameters optimized by the response surface method were: clay content of 34.09%,sintered greenhouse 1030 ° C,holding time of 105 min,and molding moisture of 24.56%.The compressive strength of the tailings sintered bricks fired according to this parameter is 22.73 MPa,and the water absorption rate is 13.52%.Compared with the single factor test,the quality of the gold ore tailings sintered bricks has been further improved. |
PDF Full Text Request