Research On Steel Slag Used As Cement Mixture

Steel slag is a waste slag produced in the steelmaking process of steel plants.Its main chemical components and mineral phase are similar to Portland cement clinker,and have potential gelling properties.However,factors such as low early activity and poor stability limit its further development and utilization.The resource utilization technology of metallurgical slag in China’s more developed countries starts late and develops slowly,and the utilization of steel slag is particularly prominent.Due to inadequate research on the properties of steel slag and the lack of resources for utilization,the comprehensive utilization rate is less than 25%,and a large amount of steel slag is accumulated,causing huge waste of resources and severe environmental pressure.This paper mainly studies the gelation properties of steel slag and slag.The mechanical properties and related hydration mechanisms of steel slag and steel slag-slag powder are analyzed and compared,which provides a theoretical basis for steel slag as a cement mixture.The subject takes converter steel slag as the research object,and uses physical stimulation to activate the steel slag.With reference to the national standard GB175-2007,the relevant performances of steel slag and steel slag-slag powder composite powder with different dosages are analyzed.The results show:（1）Steel slag alone is used as cement mixture,and the mixing ratio should be controlled within 15%.When the mixing ratio is 5%,The 3d,7d,and 28d age strengths of the steel slag cement mortar test blocks reached 90.2%,93.7%,and 96.8%of the strength of the corresponding age-grade pure cement benchmark group.（2）Steel slag-slag re-mixing,the two can play a superimposed effect to help the development of cement strength,The total mixing ratio should be controlled within 50%,50%cement,25%steel slag,25%slag test rubber sand test block,3d,28d age flexural and compressive strength of 4.3MPa,21.2MPa,8.5MPa,55MPa,Meet the 52.5 grade slag portland cement strength requirements.（3）After scanning electron microscope（SEM）and X-ray diffraction（XRD）analysis,The steel slag-mineral cement composite micropowder is similar to cement hydration products in that the structure is different,The hydration products are flaky Ca（OH）₂,tube-shaped calcium silicate gel（C-S-H）,needle-shaped ettringite（AFt）crystals,hydrated calcium aluminate（C-A-H）and other hydration products.（4）Large amounts of steel slag（above 60%）cause poor cement stability.When the content is controlled within 25%,the steel slag can be used as a cement mixture in cement production.