利用攀枝花提钒尾渣制备蒸压砖试验研究

Preparation of Autoclaved Bricks from Residue after Vanadium Extraction in Panzhihua

以攀枝花地区的提钒尾渣、石灰与黄沙为原料,采用压制成型—蒸压养护法制备了蒸压砖,研究了升降压速度、蒸气压力与养护时间对样品抗压强度的影响,分析了样品的组成与显微结构,检测了样品的综合性能及放射性指数。结果表明:提高升压速度与蒸汽压力使样品的抗压强度先增大后减小,适当降低降压速度和延长养护时间可改善样品的抗压强度。当提钒尾渣、石灰与黄沙的质量分数分别为60%、23%与17%,升降压速度为0.7 MPa/h,蒸汽压力为2 MPa,养护时间为7 h时,制品的强度及放射性指数可满足相关的行业标准。XRD和SEM分析结果表明:经过蒸压养护后,制品中形成了针棒状的托贝莫来石,板片状的硬钙硅石与无定型水化硅酸钙等物相,上述水化产物与粗粒骨料相互交织,形成致密的结构,使制品具有较高的抗压强度数。

Autoclaved bricks were prepared from residue after vanadium extraction in Panzhihua,lime and sand by compaction moulding-autoclaving maintenance method,and the effects of rise and fall speeds of pressure,steam pressure and curing time on the compressive strength of the samples were studied.The compositions and microstructure of samples were analyzed,and the comprehensive performances and radioactivity were tested.The results show that the compressive strength of the samples increases first and then decreases with the increase in pressure-increasing speed and steam pressure,and that of the samples can be improved with appropriate decrease in pressure-reducing speed and increase in curing time.When the mass fractions of the residue,lime and sand are respectively 60%,23%and 17%,the rising and falling pressure speed is 0.7 MPa/h,and the steam pressure as well as the curing time is respectively 2 MPa and 7 h,the mechanical properties and radioactivity of the products meet the relevant industry standards respectively.The XRD and SEM analysis results show that after the autoclaved curing,needle-like tobermorite,slab-like hard calcium silicate and amorphous hydrated calcium silicate are formed in the products.The hydrated products interweave with coarse aggregate to form a compact structure,giving the products higher compressive strength and lower radioactivity index.