Iron Ore Pellet Dustiness Part I: Factors Affecting Dust Generation

Iron ore pellets abrade during handling and produce dust. This study was conducted to determine what factors affect pellet dustiness, and whether dustiness can be related to the abrasion index. Factors studied included bed depth within a straight grate furnace; pellet chemistry; firing temperature; coke breeze addition; and tumble index. Abrasion indices for all pellet samples ranged from 1.9–5.0% (20 samples) and from 7.1–27.5% (5 samples). Pellets were dropped in an enclosed tower, which enabled the collection of airborne particles generated during pellet breakdown. The quantity of airborne particles generated by each pellet type was 10–100 mg/kg-drop, or 50–500 mg/kg over five drops through the tower. Pellet dustiness was predominantly affected by pellet chemistry and by pellet firing temperature. Results showed a nearly 21% increase in dustiness for every percent decrease in firing temperature – this was based on a typical firing temperature of 1280°C. Pellet dustiness was regressed to the pellet abrasion index (for AI < 5%), which yielded a correlation coefficient of 0.22. These results show that, although AI is one of the best indicators of fired pellet quality and can indicate high levels of dust, it could not explain the dustiness of good quality pellets.

The second paper (Iron Ore Pellet Dustiness Part II) explains the relationship between AI and dust for good-quality pellets; and compares fines generation between pellets fired in Straight-Grate (Traveling Grate) and Grate-Kiln furnaces.     

Microstructures and Corrosion Resistance of Al2O3—C Based Refractories to the Melts Containing Titania

The corrosion resisance of the Al2O3-C based refrac-tories in melts containing titania has been studied by quasi-station immersion and rotary immersionThe corrosion rate is decreased with the addition of graphite carbon and ZrO2 in the refractories.The corrosion mehanism of Al2O3-C refractories is the oxidization of graphite carbon by the oxides of the melts and the formation of deteriorate layer,For the Al2O3-C-ZrO2 refractories,the corrosion behavior is due to the interaction between melts and refrac-tories,The new compounds of FeO.SiO2,SiZrO4,Feo.3CaO,2CaO.SiO2 and CaO.SiO2 are formed in the deteriorate layer.     

铝炭复合材料的机械性能

对影响铝炭复合材料机械性能的诸因素，如气孔率、结合剂种类及用量、焙烧温度、石墨用量等进行了实验研究。     

钢水的钙处理与连铸用耐火材料发展的新趋势

用化学热力学和相图原理，分析了ＣａＳｉ处理钢水中钙对连铸用Ａｌ_２Ｏ_３－Ｃ质耐火材料的化学蚀机理；指出在Ａｌ_２Ｏ_３－Ｃ质控制元件的关键部位用ＭｇＯ－Ｃ质材料进行复合，是钙处理钢水连铸用耐火材料发展的新趋势。     

铝炭滑板的高温强度、断裂行为和氧化过程与添加物Al、Si的关系

Ａｌ、Ｓｉ添加物均能显著改善滑板的性能，其作用主要通过化学反应而产生的相变化来实现。分析了铝炭滑板的断裂行为。     

聚酯熔体热水中造粒传热过程的模拟

为开发聚酯熔体热水中造粒与结晶集成技术,建立了聚酯熔体在热水中的传热模型,采用Matlab语言编程进行了求解。计算结果表明,切片内的温度呈中心温度高、四周温度低的对称式温度分布,切片的直径和在热水中的停留时间是影响切片内温度分布的敏感因素;在93～99℃,热水温度对切片内温度分布的影响不明显。对于切片直径4.0mm、热水温度95℃、切片停留时间2.5s,切片内的平均温度约为199℃,可实现后续聚酯固相缩聚所要求的切片最佳结晶温度。     

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。     

Aqueous Ions in Process Water and Cake Moisture During Iron Ore Filtration

In mineral beneficiation plants, aqueous ions from the process water concentrate within the filter cake moisture. These high concentrations of ions can lead to operational issues during downstream processes. This paper examines the ionic content of iron ore slurry before it was filtered at an operating hematite beneficiation plant and compared it with the ionic content of the moisture in the resultant filter cake. Water analyses were conducted to determine the sodium, potassium, calcium, magnesium, fluoride, chloride, nitrate, nitrite, carbonate, sulfate, and phosphate concentrations in both filter feed slurry and filter cake moisture. Results have shown that all tested ions within the process are more concentrated within the filter cake moisture than in the filter feed slurry. This has been attributed to the physical and chemical interactions of these ions with the iron ore particle surfaces. Of these ions, phosphorus concentrates most with the filter cake moisture content having a phosphorus content that is 24.67 times that of the filter feed slurry.     

矾土基锆刚玉对铝碳材料性能的影响

以电熔白刚玉、熔融石英(粒度≤0.5 mm)为骨料,鳞片石墨(粒度≤0.15 mm)、电熔白刚玉粉(粒度≤0.088 mm和≤0.045 mm)、矾土基锆刚玉(粒度≤0.088 mm)为基质,热固性酚醛树脂作结合剂,压制成125 mm×25 mm×25 mm的试样,经200℃固化24 h后,在埋炭条件下经1 200℃保温2.5 h烧制成碳质量分数为28%的铝碳材料。研究了用质量分数分别为3%、6%、9%、12%的矾土基锆刚玉等量替代铝碳材料中的石墨对其常温物理性能、热态强度和抗氧化性的影响,并采用SEM分析烧成后试样的显微结构。结果表明:(1)随着矾土基锆刚玉加入量的增加,试样的显气孔率下降,体积密度增加,常温和高温抗折强度升高,抗氧化能力增强;(2)矾土基锆刚玉的加入量超过6%,试样的抗热震性显著下降;矾土基锆刚玉取代碳的量不宜超过6%。