Research On Efficient Separation Technology Of Suspended Matter In The Chemical Milling Solution

After the dilution crystallization processing, the change slot milling fluid ofaviation aluminum would precipitate Al(OH)3crystal, getting established stablesuspensions. In the processing of resue change slot milling fluid, the ultrafine grainAl(OH)3crystal was needed to separation. In this paper, according to the rapidsuspension solid-liquid separation problem, used microfiltration technology research onexperiment and equipment development.By the studying of different membrane module and operation mode ofmicrofiltration process characteristics, than to choose it is concluded that the appropriatemembrane module and operation mode, and then design the micro filtration equipment,based on the experimental study on the equipment, it is concluded that the bestoperating conditions. The results of studying are as follows:（1）During the parallel flow microfiltration of flat membrane processing,membrane flux would weaken seriously for the filter cake layer of membrane surfacecontinuous thickening, filtration resistance increasing, When operating pressure for0.016MPa, slurry concentration of20g/L, the membrane flux reduced to the initial28.5%of membrane flux in60min.（2）In the cross flow of tubular membrane processing, the filter cake layer ofmembrane surface would maintain in a certain thickness and filtration resistance,eventually got a stable membrane flux, which benefited from configuration of tubularmembrane and characteristics of cross flow operation. The operating pressure was0.26MPa, slurry concentration was40g/L, the stable membrane flux was stillmaintained at318L/(m~2h), is the initial72.7%of membrane flux.（3）Using plate membrane module and tubular membrane module for suspensionsample filter, its through liquid suspended solid concentration range were2.1~2.9mg/Land2.3~3.4mg/L, less than10mg/L. the suspension of the sample suspended solidretaining rate all can achieve above99.9%.（4）Through the flat membrane flow microfiltration and tubular membranecross-flow microfiltration characteristic researching, choose draw tubular membranemodule in cross-flow operation mode for the most suitable containing superfine particlesuspension solid-liquid separation, On this basis, designed cycle intermittent operation process optimization microfiltration process, further improve the equipment design.（5）Equipment experiments showed that rising the operating pressure ofmicrofiltration process in a certain extent would improve the membrane flux effectivelyand increasing the pressure of concentrate outlet would also increase membrane flux.Through the experiment, the optimum operation condition was: operating pressure was0.26MPa, concentrate outlet pressure was0.05MPa.（6） Equipment filter turn milling fluid, through liquid suspended solidconcentration between2.5and3.3mg/L, less than10mg/L, this experiment equipmentof chemical milling fluid of suspended solid retaining rate can amount to99.93%above,these result can meet the requirements of the technical indexes.（7）Membrane cleaning experiments demonstrated that using gas and waterbackwashing of cleaning could reduce the membrane flux for membrane fouling.Membrane flux would recover for the initial95.3%, when the operating time forequipment operation and backwashing cycle time was30min, cleaning time was10s.