氧化碱木质素制备高效水泥助磨剂

Evaluation of High-performance Grinding Aid for Cement Prepared {rom Oxidized Alkali Lignin

采用过硫酸铵氧化改性的方法降低碱木质素的相对分子质量（简称分子量，下同），增加其分子中的极性基团，制备改性碱木质素基水泥助磨剂GCL6-J，在添加质量分数0．1％（占熟料和混合材料的质量）时使粉磨水泥的45μm筛余值由空白的7．8％降低到5．3％，其助磨效能达到三乙醇胺的89．3％，其对水泥的后期抗折抗压强度达到或超过三乙醇胺，综合性能测定表明，GCL6-J属于一种木质素基高效水泥助磨剂。XPS能谱分析表明，氧化改性使碱木质素在水泥表面的吸附层厚度由氧化前的0．41nm增加为1102nm（以硅原子的能谱分析统计）；粉磨水泥样品的C1s质量分数由空白的38．11％降低为34．07％，而Ca2p和Si2p等高能活性点质量分数却由空白的8．51％、4．42％增加为10．29％、4．98％；证明了GCL6-J在水泥新生颗粒表面吸附和电荷屏蔽作用的助磨机理。

The ammonium persulfate is used to oxidize the alkali lignin to prepare oxidized alkali lignin withlow molecular weight and more polar functional groups. The prepared high-performance lignin-based grindingaid GCL6 - J is evaluated by grinding experiment, and the results show that the 45 pm screen residue valuesof the milled cements decrease from 7. 8~ to 5. 3~ at the dosage of 0. 1%（ the mass fraction in the total clinker and composite materials）, which is equivalent to the 89. 3% grinding effect of triethanolamine Thelong-term breaking and compression strengths of the milled cement using GCL6 - J reach or exceed those of triethanolamine. The combination property evaluation indicates that the 6CL6 - J is a kind of lignin- basedhigh-performance grinding aid. The XPS spectrum analysis shows that the thickness of the adsorption layer ofthe oxidized alkali lignin is 1. 02 nm（ calculated by the Si） , while that of the alkali lignin is 0. 41 nm The Cls content of the milled cement using GCL6 - J decreases from 38. 11% （blank） to 34. 07%, while the Ca2p and Si2p contents increase from 8. 51% and 4. 42% （blank） to 10. 29% and 4. 98%, respectively, which demonstrates the grinding mechanism of GCL6 - J in the milling process： it adsorbs on the new-born high energy active sites of the cement surface and masks the charge.