Positive-pressure Filtration Device Specially Used For Rare Earth Products

Rare earth elements exhibit unusual luminescence properties owing to their unique atomic structures,and their corresponding products have multiple high tech uses in industries.Greater demands are being placed on the processing technology and equipment used for abstracting rare earth elements from the precious resources.As an important processing step of rare earth products from filtering or dewatering the phosphor solution,the solid-liquid separating production technology and equipment are confronting with keeping challenge and good opportunities for development.For the requirement of production being automatically processed,this paper analyzes and improves the filtration process and a set of corresponding equipment used for rare earth products according to actual application in an enterprise.In the production of rare earth products,filtration and dewatering process is the key to design proper dewatering equipment.This paper begins with a brief analysis of the rare earth phosphor process steps and production on its requirements to the product dewatered.Drying filter cake with hot air was proposed to add to the original filtering production process,and the pipeline and devices of filtration system is optically arranged in the workshop by using Pro/E software.After the performance of an existing filter cartridge was analyzed,its new configuration was presented to improve the adhesion of cake without affecting its filter efficiency.Hence,the duration of the dewatering-process with positive pressure and the blowing-process on cake with hot air is longer enough to improve the dryness of the cake.The filtration capacity of the filter,the pressure drop through the filter cloth and filter cake were calculated,and a formula used to calculate the sum of pressure drop during the process was modeled.According to the production,the pipe,valves and feeding pump in the system were chosen.The configuration of the filter vessel was designed,and its stress and strain distributions were analyzed and mapped by using ANSYS finite element software.To improve the production efficiency and to increase the reliability during the process,the production has been automatically processed by such electrical control system like programmable logic controller(PLC),which is used to control the solenoid opening and closing,or alarming according to processing parameters,such as elapsed time and working pressure values in the vessel over each sub-process.The software and hardware design,such as constructing the circuit,properly choosing components and interfaces,is discussed in this paper.After simplified the filter configuration,four flow field models with different thickness of filter cake were built.These models respectively with different boundary and filter element configuration are used to analyze the variation of the distributions of pressuredifference for different diameters of filter holes and the mean velocity of the flow at outlet of filter,and the optimum boundary conditions and filter structure were determined based on analyzing and comparing the computing results.The key technologies of rare earth phosphor filtration equipment were researched to satisfy the actual demand in the enterprise.The equipment being designed could be used to improve the filtering accuracy and to increase dehydration rate of phosphor in the production process.Both the product quality and production efficiency of the product could be achieved,and the environment around the enterprise may be kept in healthful conditions for exhausting the cleaning effluent.The project,hence,has better economical and social benefits.