Research On The Properties Of Wind Quenched Steel Slag Used As Cement Admixture

Steel slag is the byproduct of steelmaking.Nowadays, in China, only 20% steel slag is recycled. Piles of steel slag not only takes up large amounts of land, but also pollutes the environment as well. In the New Industrial Park of Maanshan Iron & Steel Group, the annual output of steel slag reaches as much as 0.5million tons. This thesis systematically study the prospects of wind quenched steel slag used as cement adimixture,aimed at solving the technical difficulties of using steel slag as useful resources.Using XRD、laser particle size analysis and other testing technology, in-depth, the author studies the mineral composition of steel slag and the particle distribution of the cement. Experimental results show that in the same hydration age period, the steel slag and shale admixture has higher filling effects than the single-doped steel slag or the single-doped shale, that is, both have good stacking effect.Similarly the even with the similar composition of cement because of different particles size, cement-mortar strength dramaticly changes.Based on the technology research, the author found that the wind quenched steel slag has poor grindability when grinded with clinker、shale and plaster. Choosing suitable grinding aid play a key role to solve the question of wind-quenched-steel-slag’s poor grindability.The author studies the effect on the quality of cement which is produced with steel slag and steel slag with shale complex doped. The research results show that steel slag adapts to shale very well. The dual-doped methods can greatly improve cement’s working properties, that is to say, not only is the corresponding early stage strength kept, but also the late stage strength growth rate is improved.The author succeeded in the orthogonal test design by selecting proportioning optimization to carry out industrial experiments inΦ3m×11m cement mill. The experimental results show that:With the production going on, the back coarse powder material increased apparently,cyclic load enlarged by a wide margin, selective grinding appears to bring the difficulty to normal production; choosing suitable additive can reduce adverse effects caused by poor grindability; rational design of formulations can produce high-grade cement. If the wind quenched steel accounts for 5-10% of total mass of cement instead of the blast furnace slag, the Grade 42.5 ordinary portland cement can be produced in line with the requirements of GB 175-2007 " Common Portland Cement"; If the wind quenched steel accounts for 10-20% of total mass of cement instead of the blast furnace slag, the Grade 32.5 composite cement can be produced in line with the requirements of GB 175-2007 "Common Portland Cement".