【作者】 黄文锋；

【导师】 刘炯天；

【作者基本信息】 中国矿业大学 ， 矿物加工工程， 2010， 博士

【摘要】 细粒物料的脱水广泛应用于各行业。细粒物料脱水理论大多停留在实验室研究和一些经验和半经验公式。细粒物料的脱水装备和技术,在结构、能耗、自动化、设备维护量等方面仍存在着不足和缺陷。以经验和半经验公式为指导,结合生产现场生产实际,设计开发具有自主知识产权的细粒物料脱水新装备具有重要意义。论文分析了细粒物料脱水工艺存在的问题,对采用压滤和过滤技术的各类设备的优缺点进行了综述。论文回顾了离心脱水理论和鲁斯(Ruth)等人提出的一般过滤微分方程为基础的脱水理论,以及这些理论在实际工业生产中的应用。论文在泊谡叶公式基础上,推导出了适用于正压过滤理论的经验公式,并以此为基础,设计了正压水平过滤装置。为充分证明正压过滤的特点和优点,从理论上分析了正压过滤沉降及其粒度效应、毛细脱水和粗重颗粒的截留机理以及气压脱水机理。采用对正压水平过滤滤饼分层切片的方法,证实了正压过滤沉降在不同条件下所产生的作用和粗颗粒的截留作用。采用对正压水平过滤滤饼分区采样的方式,说明了“气排水”过程的存在,为正压过滤装置的研发提供了理论支撑。在经验和半经验公式的指导下,根据国家有关实验规范,测定了研究对象的密度、滤液的黏度、滤饼的比阻和滤饼的可压缩性,并与正压过滤理论进行了联系。比较了机械压滤滤饼和正压过滤滤饼在比阻和滤饼结构的区别,结果表明正压水平过滤滤饼具有结构上优点和较低的比阻。研究了压力、浓度、粒度组成等工艺参数变化对正压过滤过程的影响,通过正交试验研究了三个因素之间的交互作用,结果表明三因素之间没有交互作用,给料浓度越大、过滤压力越大,滤饼的水分越低,过滤处理量越大。通过工业试验验证了滤饼的结构特点和计算机拟合的结果是一致的。论文比较了正压水平过滤、加压过滤和水平带式真空过滤。论述了正压水平过滤滤饼的特点,并和目前常用的过滤技术得到的滤饼进行了结构上的比较,进而从过滤理论、工作原理和过滤结果三个方面进行了分析,总结了正压水平过滤装置过滤脱水的特点。同时,论文指出了正压过滤装置工业化过程中,在滤布选择、机体结构强度设计等方面要日臻完善。更多还原

【Abstract】 Dehydration of fine-grained materials was widely used in various industries. Technology in terms of dehydration of fine-grained materials are mostly still in the laboratory research and some empirical or semi-empirical formulas. In terms of equipment and technology on dehydration of fine-grained materials, there are some gaps and imperfections in structure, energy consumption, automation, equipment maintenance capacity etc. Under the guidance of empirical and semi-empirical formulas and combined with the actual situation of production site, it is more meaningful to design and develop new equipment for fine-grained materials dehydration with independent intellectual property rights.This research has a detailed analysis of the problems incurred during the fine-grained material dewatering process and serious revelations about the advantages and disadvantages of various types of equipment using filtration technologies This paper reviews the theories of centrifugal dewatering and dehydration theory based on a general filter differential equations by Ruth and others and explains the actual experience of the use of these theories in industrial production. The author deducted empirical formula of pressure filtration on basis of Park Su-Ye formula and then designed the positive-pressure filtration devices at the horizontality of filter medium. In order to fully explain the characteristics and advantages of positive-pressure filtration, interference settlement and its effect of grain size, capillary dehydration heavy particle retention and barometric pressure dehydration mechanisms were introduced in the discourse of the theory, which explains the filter cake structure by positive-pressure filtration and the "air drainage" mechanism more in-depth and provide strong technical support for research and development of positive-pressure filtration devices.This research confirmed positive-pressure filtration hindered settling’s effect under different conditions and the rejection of the role of coarse particle through stratified slice method to positive-pressure horizontal filter cake. Using the way of areal sampling to positive-pressure horizontal filter cake, process of“drainage by gas”was verified, and technical support was provided for researching on positive-pressure filtration equipment.Under the guidance of the past experience and the semi-empirical formula and by means of the national standards, this research measured the density, the viscosity of filtrate, cake specific resistance, filter cake compressibility and other contents, and contacted with positive-pressure filtration theory. The paper compared the specific resistances and structures of filter cakes respectively by mechanical filtration and positive-pressure filtration. The results showed the constructional advantages and lower resistivity of filter cakes by positive-pressure horizontal filtration, provided a premise for the research on Positive-pressure horizontal filtration. On this basis, paper investigated filter materials in single parameter change about different pressure, concentration and gradation composition effect on process of Positive-pressure horizontal filtration, and discussed reciprocal action of various factors. The results showed that no interaction was found between three factors. The more the material concentration and filtration pressure were higher, the more filter mass moisture was lower and treatment capacity was larger. The paper confirmed that the structural features of filter mass consistent with computer simulation result by industrial test.The research compared positive-pressure filtration, pressure filtration and horizontal belt vacuum filtration, discussed positive-pressure filter cake’s feature and compared with the filter cake’s structure using currently filtering technology. Differences in application of filtration theory, the working principle and filtering results were analyzed. Advantages of positive-pressure filtration dewatering devices can be summarized.Meanwhile, the paper pointed out that there is still much work to be done for industrial application of positive-pressure filtration equipment. The choice of the filter cloth and the design of equipment’s structure strength have to further improving.There are 72 figures, 93tables, 135 references in this paper.更多还原