硼精矿活化焙烧与加压碳化过程机理研究与工艺优化

发布时间：2018-05-06 18:31

  本文选题：硼精矿 + 活化焙烧　； 参考：《天津科技大学》2017年硕士论文

【摘要】：硼化合物是重要的化工原料,广泛用于冶金、建材、农业、纺织、国防等领域。在我国硼资源中,用于生产硼化合物产品的原料主要为硼镁矿和硼铁矿,但长期的开采导致含硼量较高的硼镁矿资源匮乏,品位较低的硼铁矿资源逐渐成为生产硼产品的主要原料。合理地开采和利用低品位硼铁矿资源,对解决我国硼资源短缺以及推动硼工业发展有着重大意义。针对我国硼化工现行生产过程存在的硼收率偏低,硼精矿活化焙烧机理不明确,浸出液碳解过程条件苛刻等问题,本文以硼铁矿经磁重选后的硼精矿为研究对象,系统开展了硼精矿活化焙烧与浸出液加压碳化过程机理研究和工艺优化。本文取得的主要创新性进展如下:1、系统地考察了温度、时间、焙烧气氛等焙烧条件对硼精矿反应活性的影响,发现硼精矿的反应活性的提高可以通过调节焙烧温度和时间,以及使用添加剂来实现,焙烧气氛对其影响较小。当焙烧温度在670～700℃,控制粒度d0.5为69.1μm左右,加入5g添加剂碳酸钙5g,空气气氛下焙烧2.0h反应活性可达到84.00%。2、利用TG-DSC、XRD、SEM、EDS等测试方法,对硼精矿焙烧过程中含硼组分和非含硼组分的物理化学变化进行了研究,结果表明,硼精矿中含硼组分主要以硼镁石和硼镁铁矿的形式存在,矿石的晶体结构复杂,硼镁石和硼镁铁矿共生关系密切。焙烧过程中,磁铁矿被氧化,硼镁石脱水分解生成易于浸出的遂安石,蛇纹石脱水分解生成镁橄榄石,白云石分解为氧化物,这些物相的反应促使矿石颗粒变得疏松,比表面积显著增大,因此硼精矿的反应活性提升。3、对焙烧后的硼精矿(熟硼矿)进行碳解浸出,系统考察了温度、时间、液固比等焙烧条件对硼精矿反应活性的影响。结果表明,加入钠盐的类型对反应的浸出率无影响,钠盐的加入量、反应温度和液固比对碳解反应影响较小,CO2是碳解反应的主导因素。碳解100g矿粉过程中,液固比为1.7: 1,反应时间为1Oh,加入Na2CO3的质量为12.8g,反应温度为135℃,通入浓度98%、压力为0.8MPa的C02气体,加入添加剂活性炭5g,浸出率达到峰值,为85.82%。4、研究了硼精矿碳解浸出过程机理。结果表明,碳解浸出过程中,熟硼矿中仅有遂安石反应,其余组分基本不参与发生反应。在Na2CO3溶液中高温高压浸出,通入CO2气体下,遂安石水解,硼进入溶液相与Na+反应生成硼砂,而镁与C3O2-反应生成MgCO3和4MgCO3·Mg(OH)2·4H20进入残渣相中达到分离硼镁目的。在碳解过程中影响浸出率的关键因素为CO2的反应速率。
[Abstract]:Boron compounds are important chemical materials, widely used in metallurgy, building materials, agriculture, textile, national defense and other fields. Among the boron resources in China, the raw materials used to produce boron compounds are mainly borite and boron iron ore, but the long term exploitation results in the shortage of boron mineral resources with high boron content. The low grade boron ore resource has gradually become the main raw material for the production of boron products. The rational exploitation and utilization of low grade boron iron ore resources is of great significance to solve the shortage of boron resources and promote the development of boron industry in China. In view of the problems existing in the present production process of boron chemical industry in China, such as low boron yield, unclear activation roasting mechanism of boron concentrate and harsh conditions of carbon hydrolysis process of leachate, boron concentrate after magnetic gravity separation is taken as the research object in this paper. The mechanism and process optimization of activation roasting of boron concentrate and pressure carbonization of leaching solution were carried out systematically. The main innovative progress in this paper is as follows: 1. The effects of calcination conditions such as temperature, time and roasting atmosphere on the reaction activity of boron concentrate are systematically investigated. It is found that the increase of reaction activity of boron concentrate can be achieved by adjusting the calcination temperature and time. The effect of roasting atmosphere on it is small. When the calcination temperature is 670,700 鈩，

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