Study Of The Preparation Of Ceramic Tiles With Cyanide Tailings

Owing to problem of resource utilization of cyanide tailings rich in CN^-and heavy metals,this paper prepared a kind of 60 wt%cyanide tailings incorporated ceramic tiles with high performance and good environmental effect.Meanwhile,the relationship between the chemical composition of billet and the performance of ceramic tiles was studied.Some analytical techniques,like X-ray fluorescence analysis?XRF?,X-ray diffraction analysis?XRD?and thermo gravimetric-differential thermal analysis?TG-DSC?,were employed to investigate the factors and mechanism affecting the ceramic tiles performance.Moreover,the relationship between the release sulfur and ceramic tiles performance was also discussed.Firstly,the chemical composition and mineral composition of cyanide tailings were analyzed,then the process properties and firing performances were studied.The results showed that the cyanide tailings mainly consisted of quartz,feldspar,and pyrite,in which the chemical composition was similar to ceramic billet.The cyanide tailings demonstrated some superior properties in fineness,flowanility of slurry,drying shrinkage,coefficient of drying sensitivity and strength of green body after drying.In this paper,a ceramic product with water absorption of 1.00%and rupture strength of 56.7 MPa was obtained after firing.It is indicated that the utilization of cyanide tailings in ceramic manufacturing could contribute to the safety and resource utilization of cyanide tailings.Secondly,the relationship between composition of billet and the performance of ceramic tiles was studied.This paper discussed the relationship between the types and content of auxiliary materials,firing system and ceramic tiles performance systematically.The results showed that cyanide tailings has a high content of pyrite which brought large ignition loss and the falling temperature,and the defects such as deformation,black core,and drum defects were appeared easily in process of high temperature firing.Adding bauxite could help to improving the firing temperature,and adding Laiyang soil and flotation tailings could help to suppress the production of black core and drum defects,then the comprehensive performance of cyanide tailings ceramic tile could be optimized.And the comprehensive performance of ceramic tiles could be further improved by reducing the firing temperature and adjusting the burning time.Finally,the causes of black core and its influencing factors were studied.This paper studied the release law of sulfur in cyanide tailings,the formation mechanism of black core and the effect of black core on the properties of ceramic products.The results showed that loose piled cyanide tailings powder has high content pyrite,and the pyrite decomposed in vicinity of 384.5 ^oC rapidly.But the decomposition of pyrite in compacted body was affected by many factors,such as molding pressure,thickness of green body,the type of auxiliary materials,firing temperature,burning time,oxygen concentration in the kiln and et al.During the actual firing process,the internal sulfur of the body was not completely released,and a part of Fe²⁺did not completely oxidize into Fe³⁺,resulting in the formation of black core and drum defects which reducing the comprehensive performance of ceramic tiles.