羧甲基淀粉钠提高球团强度的机理

The mechanism of improving pellet strength by carboxyl methlated amylum

对市售食用红薯淀粉进行羧甲基化 ,制备出羧甲基淀粉钠 ,并对合成反应机理进行了分析 .以羧甲基淀粉纳为有机粘结剂进行造球试验 ,冷固球团干球抗压强度达 3 2 2 .8N/个 ,落下强度为 16.18次 /m ,生球爆裂温度为 82 0℃ .此外 ,对羧甲基淀粉纳提高球团强度的机理进行了研究 ,发现当生球中加入羧甲基淀粉钠 0 4 % (质量分数 )时 ,颗粒表面张力接触角由 4 8°降至 5°,粘滞力随之提高 .光电子能谱研究表明羧甲基淀粉钠的极性基团在铁矿表面的键合使得Fe的 2p轨道能由 711eV降至 710 .2eV ;极性基团的表面化学吸附是提高球团强度的重要因素 。

The carboxyl methlated amylum was produced, the reaction mechanism was analysed. Using it as organic binder in pelletizing, the dry pellet compression can go up to 322.8 N per ball,drop number to 6.67 times per 0 5 m,green pellet shock temperature is up to 820 ℃.In palletizing, the carboxyl methlated amylum makes the contact angle of particles surface decrease from 48° to 5° and the ZeTa potential decrease from 24.5 mV to 38.5 mV. XPS analysis indicates that polar group bonded on iron ore surface make the electron energy of 2p orbit of iron decrease from 711 eV to 710.2 eV, After analysing the behavior of polar group and organic chain of the organic binder, we consider that the chemical adsorption of polar group on iron ore surface may be the most important reason for improving the strength of pellet, and the special annually netty structure of the chain contributes to improving the pellet′s strength and the green ball′s shock temperature.