摘要
为实现菱镁矿尾矿的资源化回收利用,本研究使用高温焙烧与水热固化联合工艺,首先将低品位菱镁矿矿石焙烧分解为方镁石MgO以提高其反应活性,进而在高温饱和水蒸气环境中与硅灰中的活性SiO_2发生化合反应,利用结晶性水化硅酸镁如滑石类晶体的生成与聚集提高水热固化体的力学强度。经系统试验研究,焙烧活化及水热固化过程的工艺参数建议为:焙烧条件800℃、1 h,原料配比MgO掺量50%、用水量40%;水热反应温度200℃、时间6 h。在此条件下,菱镁水热固化体的抗压强度可达16.75 MPa。研究结果对低品位菱镁矿石、水镁尾矿、硼泥等工业废弃物的回收利用具有一定指导意义。
With a purpose of realizing the resourced utilization of magnesite tailings, a feasible way is proposed in this work with the combination of high-temperature calcination and hydrothermal solidification. The low-grade magnesite was preliminarily transferred from MgCO_3 into MgO with improved activity, which subsequently combined with silica fume（strengthening additive） under the atmosphere of saturated steam in elevated temperature. A remarkable strength was obtained from the hydrothermally solidified specimens, which should be attributed to the generation and aggregation of magnesium silicate hydrate in high crystallity, i.e. talc. After a systematic investigations of the preparation process, the conditions for the high-temperature calcination and hydrothermal solidification were suggested to maximize the mechanical strength up to 16.75 MPa in the as-prepared specimen, i. e. the calcination was carried out at 800℃ for 1.0 h, while the MgO content of 50 % and water content of 40 % were controlled simultaneously in the starting materials, and the hydrothermal solidification was performed at 200℃ for 6 h. The results must be helpful to accelerate the recycled utilization of such industrial wastes as low-grade magnesite, brucite tailings or boron slurry etc.
出处
《矿产综合利用》
CAS
北大核心
2018年第1期92-95,共4页
Multipurpose Utilization of Mineral Resources
基金
住房和城乡建设部研究开发项目(2014-K4-029)
关键词
菱镁矿
水热固化
焙烧
硅灰
建筑材料
Magnesite
Hydrothermal solidification
Calcination
Silica fume
Building materials
