Properties and mechanism of steel slag based shield powder/rubber composites

Steel slag shield powder (shield powder for short)/rubber composites were prepared by rubber industry formulations based on the research results of preparing steel slag based shield powder by utilizing an ultra-fine vertical mill and steel slag. The mineral composition, chemical composition, particle size distribution, structural composition, microstructure, and thermal stability of the shield powder/rubber composite material were tested, and the relevant mechanisms of using the shield powder in rubber industry formulations were explained at the microscopic level. The results show that the shield powder has good compatibility with the rubber matrix when the proportion of shield powder replacing carbon black is 5%-10%(mass fraction, the same as below).The tensile strength of shield powder/rubber composites is 16.16-17.06 MPa, which is higher than 15 MPa. The tensile elongation is 619.8%-668.21%, which is higher than 350%. The abrasion is 130-196 mm3, which is less than 200 mm3.All values meet the requirements of national standards. When the replacing proportion is 5%, the vulcanization time of the shield powder/rubber composites is shortened and the vulcanization rate index is increased. When the shield powder/rubber composites burn, SiO2 in the shi eld powder reacts with sulfur radicals, Fe, Zn, and Al, creating the Si-Mg flame retardant system, Si-Al flame retardant system, and Si-Fe smoke-extinguishing body. Furthermore, the shield powder and the rubber system are linked to create a dense carbon layer, which inhibits the partial heat transfer and the flame spread.