| Ball mill is a universal equipment for crushing materials,however,its energy utilization rate is very low,about 3-10%.Therefore,improving the energy utilization rate of ball mill has been a subject of concern.On the other hand,the use of ball mills to grind industrial solid waste such as fly ash to a high specific surface area can greatly improve the potential activity of the waste slag.However,there are few studies on the grinding parameters of ball mills for small size of fly ash materials and few studies on grinding aids for ultrafine powders with high specific surface area(≥600 m~2/kg).Therefore,this paper mainly focuses on these two aspects to provide a basis for improving the energy efficiency of grinding small-sized materials.Firstly,the effect ofΦ30mm,20mm,15mm,10mm and 5mm on the grinding effect of fly ash was investigated,and the results showed that the optimal ball diameter was 15mm.Then,by calculating and considering the actual grinding situation,five gradations ofΦ17mm andΦ0.9mm,Φ17mm andΦ1.1mm,Φ17mm andΦ1.3mm,Φ17mm andΦ1.5mm andΦ17mm andΦ1.7mm were selected for the grinding test.The steel ball gradation of 70%Φ17mm and 30%Φ1.3mm was found to be the best match.On the basis of the above gradation study,the grinding effect of fly ash was studied when the filling ratio was 30%,40%,50%,60%,70%and 80%,and the best grinding effect was found when the filling ratio was 60%.Compared with the filling rate of 30%,increased the output by 76.6%,and reduced the electricity consumption by 12%.Secondly,for the current situation that the product is ultrafine powder with less grinding aid research,a total of 12 grinding aids,such as formic acid,ethylene glycol,1,2 propylene glycol,triethanolamine,glucose,glycerol and triisopropanolamine,were selected to study their grinding aid effect on fly ash grinding,and the results showed that glucose had the best grinding aid effect,and when its dosing was 0.04%and the grinding time was 120 min,the fly ash ratio The surface area was increased by 5.2%compared with that without grinding aid.It was also found that different grinding aids have different grinding aid effects at different grinding stages.The analysis showed that the excellent grinding aid effect of glucose was mainly derived from its high OH-content per unit mass and,therefore,its high bond-breaking bonding with the nascent surface of fly ash,which produced a significant grinding aid effect.Finally,the effects of glucose as grinding aid on cement properties were investigated,and the setting time,mechanical strength,hydration product components and microstructure of 30%ultrafine fly ash blended cement were studied based on the current situation that ultrafine fly ash blended cement under hydrothermal conditions is less studied.The results showed that glucose had no adverse effect on the performance of the cement,and its compressive strength at 3,7 and 28 days increased by 46.8%,29%and 15.1%,respectively,compared with that of pure cement cured at 20°C when the curing temperature was 85°C.Compared with the curing at room temperature of20°C,the higher curing temperature can better utilize the potential effectiveness of fly ash.Based on the comprehensive analysis of TG,XRD and SEM,the results showed that the hardened slurry with high specific surface area fly ash was more dense under hydrothermal conditions. |
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