The Experimental Study Of Mechanical Spraying Iron Tailing Sand Dry Mixed Mortar

With the increasing demand of mining engineering for mineral resources,more and more iron tailed ore is produced by mineral processing,and the comprehensive utilization of iron tailed ore has become an urgent topic.On the other hand,the ordinary sand in the wall plastering mortar is becoming less and less due to water and soil loss which is caused by the illegal mining of river sand and mountain sand from time to time.The solution is to mix iron tailing sand into wall plastering instead of common sand,which can not only make good use of solid waste,but also reduce the exploitation of common sand.Compared with traditional mortar,dry mixed mortar is more stable in property and better in quality.Therefore,dry mixed mortar,with its advantage of being easy to store and use,can be used to avoid waste of raw materials,conserve energy and protect the environment.At the same time,the emergence of mechanical spraying has effectively alleviated the shortage of technical workers and the instability of manual plastering.However,since this construction method has a high demand for mortar,it cannot copy the mortar proportion of manual plastering.To solve these problems,on the basis of a series of tests this paper first studies the influence of mortar raw materials on mortar performance,and then optimizes the mix proportion of mortar.Finally,mechanical spraying method of the dry mixed mortar of iron tailed ore sand with the best performance is simulated and analyzed on site,the result of which is compared with the traditional manual mortar plastering method.The main research work is as follows:(1)It is preliminarily determined that the optimal content of each component is 60% of iron tailing sand replacement rate,0.2% of cellulose ether,1% of rubber powder,and 1% of expansion agent 10%.This result is based on analyzing the influences of iron tailing sand replacement rate on the mechanical properties of mortar,cellulose ether on the water retention of mortar,rubber powder on the flexural compression ratio and tensile bond strength of mortar,and the influence of expansion agent on the dry shrinkage of mortar.(2)It is also determined that the left and right divergence of the optimal amount of each component is four levels of the amount of each component in the orthogonal test.With range analysis and variance analysis of orthogonal test,the extent of the impact of each component on mortar performance was studied.Finally,the optimal mix proportion of mortar is estimated as 1 / 3 of cement / sand,20% of cement quality as grade fly ash,0.3% of cement quality as water reducing agent,50% of iron tailing sand,0.15% of cellulose ether,1.5% of rubber powder and 10% of expansion agent.(3)After setting the mortar mix ratio,mechanical spraying and manual plastering are used to simulate the construction on site,and a comprehensive comparative analysis is made from the aspects of materials,construction methods,economy and others.The results show that the mechanical spraying plastering has high bonding strength,with obvious improvement in hollowing,cracking and falling off of plastering layer in plastering engineering.Besides,the comprehensive cost can be 1.05 yuan per square meter less than that of manual plastering.Therefore,it is worth applying widely.