Study On Autoclaving Lime Sand Brick Using Copper Tailing

How to make good use of copper tailings is a difficult problem that puzzled the society at all times. There are existed some defects in almost all the traditional disposal measures. Much research focus on the association between the techniques parameters and the performance of new type of wall material which used the copper tailing as the raw material in this paper. Main research works are as follows:First of all, recent utilization of copper tailing and the strength mechanism of lime-sand-brick were analyzed and summarized, and the feasibility of technical project was confirmed.Secondly, influences of factors that included calces breeds, A-CaO, grind sands, C/S rate, autoclaving system, molding pressure and the rate of water containing to macroscopical performance of autoclaving copper tailing lime-Sand-brick were researched by experiment. Technics parameters, which used in practical production, were confirmed based on research results. Experimental results showed that mechanical performance of samples were improved with the increase of dosage of A-CaO and grind sands, the rate of C/S. Mechanical performance of sample can be heightened effectively by improving autoclaving temperature and molding pressure properly. Ordinary admixtures such as gypsum and water glass can lightly improve the strength of lime-sand-brick. The strength of autoclaved sample raised largely by carbonizing. The confirmed final mix rate and technics parameters used in production as follows:Calces : sand power : sand : copper-tailing is equal to 1: 1: 3: 5, quality ratio);Molding pressure is 20 MPa; Speed of pressure infliction is 1~2kN/s; Autoclaving temperature is 185℃; Autoclaving time is 7.5~8.5h; Autoclaving system adopted is 2+8+2.Finally, microcosmic performance and strength-formed mechanism were studied by microcosmic analysis methods such as BET, XRD and SEM. Combined with the experimental results, strength developed mechanism was explained. Results showed that main hydration production exist mostly as the form of 1.13nm tobermorite crystal,plus with a little CSH (B) which do not have incompletely crystallization controlled with the technics foregoing. Andradite, which is the main mineral component of copper tailing, belongs to inert ingredient, lead to tailing mineral mainly as the framework-formed and filling matter in production. Generally hydration degree of copper tailing was indistinct. SEM experiments discover that small amount of quartz crystal contained in copper tailing participated in hydration reaction, but the degree is insufficient. Porosity of carbonized sample reduced in evidence and the distribution of hole changed largely, interior aperture was subdivided.