Formation of Friedel's salt using steel slag and potash mine brine water

摘要

The increasing depth and widening scale of potash mines are suggestive of the use of mortars with greater homogeneity and fluidity properties for mine backfills. Results of the experimental investigations discussed herein indicated that the flow property and the later strength of mortars can both be satisfied through the utilization of steel slag (SS) as a binder in potash mines. Paste samples were evaluated in terms of the hydration mechanism for the mixture of brine water (liquid waste from potash mines) and SS, and were found to achieve a compressive strength of 10 and 15 MPa after 28 and 60 curing days, respectively. An analysis carried out for the microstructure of the pastes revealed C-S-H gels and Friedel's salt being the main hydration products in the system, in which active interpenetration between the substances contributes to the enhancement of the paste's strength. Impure ions in the system can be fixed to improve the stability of the filler through the formation of Friedel's salt. Overall, the findings of the present study confirmed that SS exhibits a latent hydraulic behavior and can be used as a binder in mortars for long-distance transportation in potash mines. (C) 2019 Published by Elsevier Ltd.