Agglomeration of Hematite Concentrate by Starches

Starches of varying solubilities were investigated as a partial and full bentonite replacements. They were found to be suitable for the pelletization of iron ore concentrate. When utilizing starches of varying solubility as a direct bentonite replacement, dry compression strengths increased by nearly 300 N, as compared to bentonite alone, with the highest solubility starch. This implies that on an equivalent mass basis, starch is a far superior binder than bentonite prior to 500 °C. Above this temperature bentonite became the dominating binding factor as starch had combusted and the strengths due to starch were los(t. As a partial bentonite replacement, starch again shows increasing compression strength. The highest strengths were observed where the highest solubility starches were used. Further study has indicated that starch is comprised of insoluble starch granules and soluble starch chains, the latter being the only viable binding agent.     

高炉用Al_2O_3－C砖的研制

本工作研究了高炉用Ａｌ２Ｏ３－Ｃ砖的化学组成、烧成温度对试样性能的影响，并借助光学显微镜和扫描电镜对减侵蚀后的Ａｌ２Ｏ３－Ｃ和高铝试样进行了分析，讨论了Ａｌ２Ｏ３－Ｃ砖抗碱性优于高铝砖的原因。     

铝碳材料与稀土钢夹杂物的反应

炼钢时添加稀土是提高钢材品质的有效途径,但在浇铸过程中浸入式水口容易发生堵塞。通过SEM、EDAX、XRD分析浇铸稀土钢后铝碳质浸入式水口的显微结构以及附着物的相组成,发现附着物以稀土铝酸盐和钙黄长石为主。低熔点液相的形成以及Ca2 与刚玉的反应对附着的发生起促进作用,并对附着发生的机理进行了分析。     

铝碳滑板的高温力学性能研究

采用高温弯曲应力-应变试验方法和水冷法研究了3种含碳滑板(2种铝碳质,1种铝锆碳质)在不同温度下的应力-应变关系、抗折强度以及不同热震温差下的抗热震性能。结果表明1)含碳滑板材料在室温~1400℃的应力-应变关系分为弹性变形和塑性变形两个阶段在弹性变形的温度段,其断裂方式是典型的脆性断裂;在塑性变形的温度段,其断裂方式呈现韧性断裂特征;2)随着温度的升高,含碳滑板材料的热态抗折强度首先略有增大,到达转折温度(800℃)后开始减小,1400℃时试样的热态抗折强度约为13MPa;3)在ΔT=1200℃(水冷)条件下,铝碳滑板热震后的抗折强度保持率为43%,引入ZrO2可以改善其抗热震性,而用特级高铝矾土熟料部分替代刚玉会降低其抗热震性。     

Al和Al-Si加入量对Al2O3-C材料高温性能的影响

在板状刚玉颗粒、板状刚玉细粉、α-Al2O3微粉和石墨含量(质量分数,下同)分别为65%、27%、6%和2%的Al2O3-C材料中,分别以5%、8%和11%的Al粉或Al-Si复合粉(8%Al 1.5%Si和8%Al 3%Si)替代等量的板状刚玉细粉,外加3.5%的热固性树脂混练均匀,成型后于800℃埋炭热处理3h。在埋炭条件下检测试样400~1400℃的热态抗折强度、200~1400℃的应力-应变、常温~1500℃的热膨胀率以及试样的抗热震性和抗氧化性,并对部分试样进行了XRD、SEM和EDS分析。结果表明(1)随着温度的升高,试样的热态抗折强度表现出先降低,后快速升高,最后慢速升高的变化趋势;温度≥1000℃时,试样的热态抗折强度随Al粉加入量的增多而提高;在加入Si粉后,试样的热态抗折强度进一步提高。(2)试样在低温时即产生塑性变形,一直到1400℃仍处于塑性变形阶段。(3)试样的抗热震性随Al粉加入量的增多而提高,在加入Si粉后继续小幅提高。(4)试样的抗氧化性随Al粉加入量的增加而提高,加入Si粉后由于形成致密的氧化层结构,抗氧化性进一步提高。