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摘要:
柴达木地区盐湖镁资源储量丰富，伴随锂和钾资源的开发利用会副产大量的富镁副产物。为提高盐湖镁资源利用率，本文以MgCl2与电石渣制备的Mg(OH)2为原料，研究煅烧工艺对煅烧产物粒径、比表面积、活性MgO含量、凝结时间的影响，并以煅烧产物为原料制备MOC试件，研究煅烧温度和原料配比对MOC试件的影响。研究结果表明：随煅烧温度的升高和保温时间的延长，煅烧产物的比表面积逐渐降低，粒径呈先降低后增加的趋势；随煅烧温度升高和保温时间的延长，煅烧产物中活性MgO含量逐渐增加，煅烧产物的凝结时间逐渐延长。当原料的煅烧温度为600℃，活性MgO与MgCl2摩尔比为6，MgCl2溶液波美度为27时MOC试件抗压强度较高，且抗压强度随龄期延长而逐渐增加。
Abstract:The salt lakes in Qaidam area are rich in magnesium resources. Along with the development and utilization of lithium and potassium resources a large amount of magnesium-rich by-products will be produced as by-products. In order to improve the utilization rate of magnesium resources, this article uses Mg (OH)2 prepared from calcium carbide slag and MgCl2 as raw materials to study the effect of the calcination process on the particle size, specific surface area, reactive MgO content and setting time of the calcined product. MOC specimens were prepared from the calcined products. The effects of calcining temperature and raw material ratio on the MOC specimens were studied. The results of the study show that the specific surface area of the calcined product decreases gradually with the increase of the calcination temperature and the extension of the holding time, and the particle size tends to decrease first and then increase. With the increase of calcination temperature and the extension of holding time, the reactive MgO content in the calcined product and the setting time of the calcined product increases gradually. When the calcination temperature of the raw material is 600℃, the molar ratio of reactive MgO to MgCl2 is 6, and the Baume degree of the MgCl2 solution is 27, the compressive strength of the MOC specimen is high, and the compressive strength gradually increases with age.
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表 1 原料的化学组成/%
Table 1. Chemical composition of raw materials
名称 酸不溶物 Cl- Al3+ Ca2+ K+ Mg2+ Na+ SO42- SiO2 未洗涤 0.22 9.62 0.30 4.16 0.22 33.81 0.62 0.57 0.34 洗涤样 0.76 0.84 0.38 1.62 0.038 35.78 0.23 0.53 1.47 
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表 2 MOC试件的原料摩尔配比
Table 2. Molar ratio of raw materials for magnesium oxychloride cement specimens
编号 煅烧温度/℃ 与MgCl2摩尔比 MgCl2溶液的波美度/°Bé 1 500 6 27 2 600 6 27 3 700 6 27 4 600 5 27 5 600 7 27 6 600 6 30 7 600 6 24
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表 3 不同煅烧产物制备的MOC试件的28 d龄期物相组成及含量
Table 3. Crystalline phases and their quantity of 28 day age of MOC specimens prepared from different calcinations
煅烧温度/℃ P518 MgO Mg(OH)2 SiO2 R 500 89.09 3.36 6.59 0.97 11.325 600 93.63 - 5.22 1.15 11.742 700 93.67 - 5.46 0.87 12.490
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表 4 由不同MgO与MgCl2摩尔比制备的MOC试件的28 d龄期物相及含量
Table 4. Crystalline Phases and their quantity of 28 day age of MOC specimens prepared from different molar ratios between MgO and MgCl2
MgO与MgCl2摩尔比 P518 MgO Mg(OH)2 SiO2 R 5 98.89 - 1.00 1.11 12.386 6 93.63 - 5.22 1.15 11.742 7 90.33 8.86 1.00 0.81 12.143
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表 5 由不同波美度MgCl2溶液制备的MOC试件的28 d龄期物相及含量
Table 5. Crystalline phases and their quantity of 28 day age of MOC specimens prepared from MgCl2 solution with different baume degrees
MgCl2溶液波美度/Bé P518 MgO Mg(OH)2 SiO2 R 30 91.79 - 7.09 1.12 11.475 27 93.63 - 5.22 1.15 11.742 24 92.59 1.00 6.63 0.79 11.281
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