Experimental Study On Comprehensive Utilization Of Mixed Discharged Ash From A Heat Source Plant In Damao County

In recent years,there are still a large number of single heat source plants in most counties and rural areas in northwest my country,which produce a large amount of ash due to heating every year.However,the local flags and counties directly pile up these mixed ash and slag,and do not carry out effective and reasonable comprehensive utilization,which has caused huge damage to our environment.Increasing the comprehensive utilization of mixed ash and slag can not only solve local environmental problems,but also replace ordinary sintered clay bricks,bringing certain economic benefits to the local area.This paper takes the mixed ash and slag of the heat source plant as the main research object,and uses the mixed ash,cement and quicklime of the heat source plant as the test raw materials to prepare the new building material test block.The proportion of test blocks was firstly formulated,and the effects of ash and slag content,curing days,water-solid ratio and other variables on the compressive strength of building materials test blocks were studied,and the proportion group with better performance was initially selected.The ratio was optimized again,and then the mechanical property test and durability performance test were carried out,and then the optimal ratio of the high-strength building material test block was determined,and the reasons for its strength increase were analyzed by observing its morphology characteristics by scanning electron microscope.Finally,the economic feasibility of promoting mixed ash and slag to prepare new wall materials in Damao County is investigated and studied,and the industrialization of comprehensive utilization of mixed ash and slag is promoted to improve the comprehensive utilization rate of ash and slag.The conclusions are as follows:(1)The compressive strength of the ash and slag building materials test block will increase with the decrease of the ash and slag content,but when the ash and slag content is reduced to 80%and 70%,the increase rate of the compressive strength of the test block slows down;The compressive strength of the ash-slag building material test block will increase first and then decrease with the increase of the water-solid ratio.(2)By optimizing and improving the proportion of test blocks,two groups of optimal proportions of building materials test blocks were obtained.In group CG2,when the water-solid ratio is 5%,mixed ash:cement:quicklime=80%:10%:10%.In group EG2,when the water-solid ratio is 7%,mixed ash:cement:quicklime=70%:20%:10%.The compressive strength of the two groups of CG2 and EG2 can reach 16.67 and 23.46MPa respectively after vibrating molding and natural curing for 28 days,and other properties meet the national standards.(3)The morphological characteristics of the ash and slag building materials were observed by scanning electron microscope,and it was found that under the combined action of quicklime and cement,more calcium hydroxide could be produced,the OH~-concentration of the mixed ingredients was increased,and the pozzolan mixed with slag was stimulated.It can promote the ash and slag to participate in the hydration reaction for many times,so as to generate more ettringite crystals and improve the strength of the test block.The final study shows that promoting the industrialization of ash and slag building wall materials in Damao County can not only obtain huge economic benefits,but also bring huge environmental benefits,and solve the problem of long-term natural accumulation and unavailability of mixed ash and slag.strong feasibility.