【作者】 黄小波；

【导师】 吕学伟；

【作者基本信息】 重庆大学 ， 冶金工程， 2011， 硕士

【摘要】 在全球经济发展的低迷形势以及国内高增速经济发展的放缓等因素的影响下,中国粗钢产量已经趋近弧顶饱和阶段。为提高企业竞争力,国内钢铁企业对生产质量、工艺技术的关注会越来越高。作为最大物料处理量和最高能耗的冶金工艺过程,高炉炼铁生产环节通过提高工艺操作水平,改善入炉炉料性质等措施达到较好的技术经济效益,仍然具有较强的可行性。在中国目前的高炉炉料结构条件下,烧结矿质量的优劣对高炉生产指标有着决定性的作用。混合料的制粒效果决定着烧结料层的透气性和烧结均匀性,从而对烧结矿的产量、质量产生显著的影响。湿容量作为物料的吸水特性参数,其测试数据反映了物料吸水过程的一些重要性质,并与混合料制粒的最佳含水量有直接关系。研究湿容量在优化烧结混合料制粒工艺中的应用具有重要的理论意义与实践价值。本文研究了不同配料条件下加水量对制粒效果的影响,建立了制粒最佳配水量的预测关系式,并分析了原料性质与制粒效果的关系。得出以下结论:①在一定范围内,随混合料含水量的增加制粒的烧结生料层透气性变好,超过某一适宜含水量后料层透气性急剧恶化。即是说在较宽含水量范围内,含水量对混合料透气性指数JPU的影响呈倒“V”型;制粒后3-7mm含量及相应的制粒效率η随含水量的变化有相似的规律。②混合料从较低含水量变化到较大含水量的过程中,制粒颗粒中细粉颗粒被逐渐消耗掉,大颗粒含量增多,制粒颗粒群的粒度组成呈长大、均匀、集中化。在本文研究的9组配料方案下混合料的制粒适宜含水量在6.5～7.3%之间,对应的制粒混合料>3mm粒级含量大于均87.16%,0.7～3mm粒级的含量在6.0～12.70%之间,<0.7mm的颗粒含量小于0.2%。③随含水量的增大,制粒颗粒的分形维数呈线性减小趋势,反映了制粒颗粒群向均匀、集中化、粒径粗大化发展的趋势;粘附成球指数GIO随含水量的增加迅速达到极大值,各组混合料细粉粘附成球性都比较好;料层堆密度也随含水量的增加大多呈V型变化规律,在适宜含水量下制粒料堆密度在1.47～1.65g/cm3之间;混合料平均粒度随含水量的增多而单调递增。④混合料湿容量与适宜含水量呈线性关系,相关系数R2>0.86,表明湿容量与适宜含水量有比较显著的相关性。结合物料的分形维数、吸水特性等性质,制粒适宜含水量的预测表达式为: -129.36 38.72 (%) 2.04 2(%) 0.96 (%) 0.34-0.14 - 3.80 2 3(%)相关系数R2>0.99,该式表明除原料化学成分外,物料的吸水特性对最佳含水量也有明显的影响。⑤混合料的物理、化学性质与最佳料层透气性指数JPU的关系式为: 197.30 52.58 2 3(%) 1.04 ( )50.37 4.82 (%)23.92 (%)Al O M c k DfLO相关系数R2大于0.97。混合料的颗粒级配(Df)、化学成分、吸水特性决定了制粒的最佳透气性。更多还原

【Abstract】 Under the influence, such as the downturn of the global economic development and the slowdown of Chinese high growth of economic development, crude steel production in china will soon reach the saturation stage. To improve the competitiveness, domestic steel plants will pay more and more attention on the production quality and technical progress. As the biggest mass treatment of material and the highest energy consumption procedure, iron making process, especially the blast furnace process (BF) still has a great promotion potential in economic and technical benefit, via methods like improving operation level and the properties of charging burden into BF. Under the current BF burden structure in China, the quality of sinter ore plays a key role in the quality of BF production.Granulating effect of sinter raw materials determine the permeability of the sintering green bed and the homogenization of sinter reaction, thus has a great impact on efficiency, yield and quality of sintering process. As a typical hydrophilic feature between water and powders, moisture capacity shows an obvious impact on granulation process, whose testing curve reflects some important features during water absorption process, which determined the optimal moisture content of granules. It can make a significant meaning in theoretical study and practical application by doing some research on the effect of moisture capacity on improving granulation results of sinter mixture.The effect of moisture content on granulation results were studied under different ingredients. A predictive formula of the best moisture content in granulation was found. Relationship between raw material properties and granulation output was also discussed. Several conclusions were shown as follow:①within a certain range of moisture content, permeability of the green bed of granules will be improved by increasing moisture content of the blends. But when moisture content is greater than a threshold value, the permeability behaves dramatically worse. It means that there is an inverted type of“V”relationship between moisture content and permeability index JPU, at a broad range of moisture content. Similar phenomena were also got for mass fraction of 3-7mm after granulation and granulating efficiency.②When increase moisture content in mixture during granulation process, size composition in the granules group of mixture grows up even and centralized, due to that fine particles in mixture were gradually consumed, while the fraction of big particles increased. Optimal moisture content in this paper ranges from 6.5% to 7.3%, with a mass fraction bigger than 87.16% for size >3mm , a weight percent between 6.0% to 12.70% for size of 0.7mm～3mm and a little content of adhesion particles(<0.2%).③Fractal dimension of granules decrease linearly as the increase of moisture content. This means that the granule particle group turns out to be grown up, centralized and uniform. The adherent pelletizing index-GIO will reach a maximal value quickly by increasing water content, it seems that all mixtures in this paper show good result of GIO. Relationship between moisture content and bulk density of granules is a V type curve, the lowest bulk density for different mixtures ranges from 1.47～1.65g/cm3; Average particle size of granules increases as moisture content increases.④A linear relation between moisture content and moisture capacity was found, the correlation coefficient is bigger than 0.86, which show a significant correlation between them. Combined fractal dimension and properties of water absorption, a prediction expression for optimal moisture content is shown: The correlation coefficient R2 is bigger than 0.99, which indicated that besides chemical component, water absorption also has an influence on optimal moisture content.⑤Relationship between physical chemical properties and the best permeability index JPU of green granules bed can be illustrated by: 197.30 52.58 2 3(%) 1.04 ( )50.37 4.82 (%)23.92 (%)Its correlation coefficient R2 is greater than 0.97. The best permeability of green bed would be determined by the feature of particle size distribution (Df), chemical composition and water-absorbing properties.更多还原