2026-10-13T04:06:18Z https://www.scidb.cn/oai

10.57760/sciencedb.0119c 2026-09-03T11:11:37Z

2026-09-03 Effect of waste bischofite on low-temperature calcination of hydromagnesite and its application in the preparation of magnesium oxychloride cement doi:10.57760/sciencedb.0119c en Currently, MgO is primarily obtained through the calcination of magnesite. To ensure complete decomposition of the ore, the preparation temperature for LBMP (light-burned magnesium oxide powder) is typically maintained above 800 °C, with processing times exceeding 2 hours. This study proposes an energy-saving calcination strategy that reduces the decomposition temperature of hydromagnesite (4MgCO3·Mg(OH)2·4H2O) by incorporating trace amounts of waste bischofite. Furthermore, multiple technical approaches were employed to investigate the mechanism of this calcination strategy and its feasibility for producing magnesium oxychlorite cement. Results demonstrate that this method enables complete decomposition of MgCO3 in magnesite at 700 °C within 2 hours of calcination, yielding MgO exhibiting excellent dispersion and reactivity. During the calcination process, bischofite acts as a catalyst to promote the complete thermal decomposition of MgCO3 in hydromagnesite. Bischofite begins to decompose before the carbonate ions in hydromagnesite, creating an acidic environment inside the furnace. During the reaction between HCl and MgCO3, MgCl2 is generated, forming a thermal reaction cycle that continues until MgCO3 is completely consumed.This process effectively prevents the formation of large amounts of Mg(OH)2 induced by amorphous MgCO3 during the hydration of active MgO. Consequently, more active MgO transforms into coarse, needle-like Phase 5, filling the pores and matrix of MOC, significantly enhancing the mechanical properties of the prepared MOC. This indicates that this method can be used to prepare LBMP at lower calcination temperatures while ensuring the performance of the MOC cementitious material produced. This method not only effectively recycles waste bischofite, but the lower calcination temperature will also reduce fuel consumption, thereby reducing mineral stockpiles on the one hand and lowering carbon emissions on the other. magnesium oxychloride cement; hydromagnesite; bischofite Zhifu Zhou Lingyun An Chenggong Chang Jinmei Dong Jing Wen Weixin Zheng PUBLIC https://creativecommons.org/licenses/by/4.0/ dataset Science Data Bank