Magnesium Oxychloride Cement Prepared by the Byproduct of Li2CO3 from Salt Lake and Hydrochloric Acid

Abstract

In this study, Magnesium Oxychloride Cement (MOC) was prepared from magnesium slag, a byproduct of the production of Li2CO3 from salt lakes, and hydrochloric acid. First, the composition and activity of magnesium slag calcined at various temperatures were investigated by XRD and hydration method. Then MOC specimens were prepared with calcined magnesium slag and various concentration of hydrochloric acid. The setting time of MOC paste was measured as well as the compressive strength was conducted at 3d, 7d and 28d. The hydration products and microstructure of the specimens were analyzed by XRD and SEM, respectively. The results demonstrated that the activity of magnesium slag decreased with increasing calcination temperature. The setting time and compressive strength of MOC specimens raise first down second with increasing the concentration of hydrochloric acid. However, MOC with a high concentration of hydrochloric acid could have a high early strength. The MOC specimens prepared by magnesium slag calcined at 500 ℃ and hydrochloric acid of 6 mol·L–1 exhibited a compressive strength of 77.9 MPa and 112.8 MPa at 3d and 28d respectively