Study On Cleaner Production Technology Of Pipe-diggestion And Horizontal Pan Filtration In Bayer Process

Cleaner production technology is advanced technology, which is based on techonic advancement and aimes at energy saving, pollutants reduction and improvement of resource utilizing efficiency. Cleaner production technology intends to protect nature resources and environment from being wasted and polluted and is the main way to achieve cleaner production. As the shortage of energy and resource, more drastically competition and more strict national environmental standards, cleaner production technology has been the life and root of company development.For a long time, alumina industry of China has been developed in the extensive mode of high pollution and consumption, low efficiency. The cause that limits alumina industry's development is that the base of alumina industry of China is weak and its'technology and equipment is laggard, which leads to energy and pollution problems and prevent aluminia industry from sustainable development. So this paper thoroughly grasped the status of domestic and foreign alumina industry and commented the development trend of domestic and foreign alumina industry. Then the paper took Shandong Xinfa Huayu alumina Co.Ltd as an example and investigated its status completely. With the guide of the theory ofcleaner production and industrial ecology and the support of alumina technology and energy saving technology, the paper studied and developed cleaner production techonologies of pipe-diggestion and horizontal pan ilter in Bayer process. The cleaner production techonologies solved the problems which is high energy consumption, environmental pollution and low resource efficiency and obtained good economic benefits and environmental benefits. So the study will have better application and popularization prospects. The central contents involve:(1) Perfect the methods of calculation of material balance and heat banlance in alumina production process. According to the basic data investigated from company, raw materials and energy consumed in alumina production process were caculated and analysised detailedly. The consumption and loss of resource and energy and production and emission of waste were caculated. The results supply detailed data and information for the research of cleaner production techonology. (2) In order to solve the problems existing in alumina production, such as higher energy consumption and lower production, cleaner production techonolgy of pipe digestion was researched. Based on the investigation of digestion process, this paper analyzed key factors that influence digestion efficiency and advanced four-pipe diggestion heat-exchanger technology through analysis of digestion fundamental and equipments. Then performance of the cleaner production technology were compared with other technologies and proved to be more advanced. This paper also gived a plan that would rebuild the network of steam heat reuses in order to increase efficiency of heat utilizing. The results show that the cleaner production technology of pipe diggestion improves greatly cleaner production level of pipe diggestion process.(3) Through investigation of state of filtration process and analysis of filtration principle, key factors which impact horizontal pan filtration were definited. This paper gave a plan of cleaner production technology of secondary-unloading whose feasibility and effect in industry production were validated through industrial experimentation and applications. Also parameters such as solid content of slurry, granularity, temperature, rotate speed of horizontal pan filter and so on were optimized through industrial debugging. Results showed that the cleaner production level was improved greatly.(4) At last, the effects and benefits of the cleaner production technology applied in industry were analyzed and the results would encourage and offer other companies more experiences.