Research On Preparation The Mortars And Dry Ectration Of Iron By Baogang Roller Steel Slag

Due to its advantages of low content of free calcium oxide, good grain shape and reasonable gradation, the Baogang roller steel slag can be prepared of mortars replaced to natural sand in a certain degree; Moreover, there is amount of elemental iron in the slag and part of iron can be recovered by dry magnetic separation. This research not only can reduce the impact to the environment by the roller steel slag, but also can improve the economic benefit of the steel slag.Based on the measurement and testing to the roller steel slag, the slag was used to prepare the mortars with the several strength grades M30, M25, M20, M15, M10, M5 within 20 vol.%~100 vol.% for the natural sand. Fotthermore, with the dosage of the slag increasing the performances such as the workability, soundness and compressive strength of the mortars were researched. The effects of crushing, grinding and magnetic separation on the recovery rate of iron was studied by using the particle size fraction and various process combinations.The main results are as follows:(1) The boiling soundness of the all of mortars is qualified when the dosage of the slag was 20 vol.%~100 vol.%; while the replacement rate of the slag sand can only be 20 vol.% when the stability was tested by pressure steam method. The replacement can be increased to 40 vol.%~60 vol.% after the slag was treated by 215 oC, 2.0MPa for 1h or 160 oC, 1.5MPa for 3h.(2) With the replacement of the slag sand increasing, the unit water consumption of mortars was decreased, the apparent density was increased, and the water retention and stratification were increased slightly. When the replacement of the slag sand reached to 80 vol.%~100 vol.%, the workability was deteriorated due to the bleeding phenomenon.(3) When the replacement of slag for sand within 20 vol.%~ 100 vol.%, the compressive strength of the mortars from strength grade M30 to M5 all improved than the blank samples.(4) The fine steel slag in using magnetic separation discarding tailings and direct grinding process can be obtained separation indexes, respectively. The iron concentrate products whose content is 82.21%(83.64%) and the recovery being 52.23%(57.25%); the iron middling products whose content is 63.30%(53.53%), the recovery being 24.67%(18.59%); tailings products whose content is 13.19%(13.80%), the recovery being 23.10%, and the metal iron content is lower than 0.5%.(5) The analysis of the tailings can be found that metallic iron and magnetite in the tailings disseminated range between 5 ~ 30 microns, and the content are less than 0.5%; the iron minerals of tailings limonite and siderite that disseminated range between 5 ~ 30 microns. The iron tailings are difficult to recycle.