Research On The Structure And Performance Of Porous Aluminum Filter Materials

Compared with non-metallic porous filter materials,porous aluminum filter materials have the characteristics of high strength,high temperature resistance and recyclability.They are expected to be used in industrial gas filtration at normal-high temperature?0²50°C?.In this paper,mixed powder processing-dissolution method is used to prepare porous aluminum with a porous aluminum porosity of 50-60%and pore size of 20-80 um.The anodizing and corrosion resistance,room temperature and normal-high temperature?0²50°C?compression properties,gas permeability coefficient and filtration performance,hydrophobicity of porous aluminum were studied.Based on the above research,the porous aluminum filter material and its filter structure were designed.The main research results are as follows:?1?Porous aluminum anodizing and corrosion resistance studies have shown that:The optimum oxidation parameter for porous aluminum is as follows:H₂SO₄ concentration 160g/L,current density 2A/dm²,oxidation time 30min when using the mass loss rate of porous aluminum after immersion in 1%H₂O₂+3%NaCl solution for 96h as the criterion for anodizing process;SEM analysis showed that the porous aluminum afte anodized form a porous Al₂O₃ structure;Under the optimal anodizing parameter,the mass loss rate of porous aluminum immersed in HCl solution of pH=1 for 3h was 0.39%,and the mass loss rate was 3.9%after immersion in pH=13NaOH solution for 0.5h.,Its acid resistance is better than alkali resistance.?2?The compressive properties of porous aluminium with different porous structures at room temperature,highest temperature 250°C and after anodizing were tested.In the room temperature compression experiment,as the porosity increases,the compressive yield strength of porous aluminum decreases.When the porosity is increased from 48%to 61%,the yield strength of porous aluminum is reduced from 25 MPa to 15 MPa.When the pore size of porous aluminum with a porosity of 55%is reduced from 72?m to 51?m,the compressive yield strength is reduced from 20MPa to 19.6MPa.The effect of pore size on the yield strength of porous aluminum is lower than the effect of porosity on its yield strength.The yield strength of porous aluminum with a pore size of 50?m and a porosity of 55%was reduced from 20 MPa to 18 MPa When the temperature of the compressiom test from room temperature to highest temperature?250??of normal-high temperature.The yield strength of porous aluminum with a pore size of50?m and a porosity of 55%is reduced from 20 MPa to 15 MPa after anodization.?3?The air permeability coefficient and hydrophobicity test results show that:the relative gas permeability coefficient of porous aluminum increases as the pore size and porosity increase.At the same filtered wind speed,the filtration resistance increases as the pore size and porosity decrease.After surface hydrophobic modification,porous aluminium with pore size of 72?m and porosity of 48.7%changed from contact angle 0°to 92.47°.Hydrophobization of the porous aluminum surface is achieved.As the pore size and porosity decrease,the surface tension of the porous aluminum solid-liquid interface decreases,the contact angle increases,and the hydrophobicity increases.Based on the theoretical formula of fiber filtration,the relationship model between porous aluminum pore structure and particle filtration efficiency was established,which has guiding significance for the design of porous aluminum pore structure.?4?Based on the above research on porous aluminum,combined with the basic performance requirements and filtration principle of filting,Porous aluminium filter material with gradient pore structure of 1.5 m m matrix?porosity 50%,average pore size 50 um?+0.5 mm surface layer?porosity 50%,average pore size 4 um?was obtained.On this basis,the filtration efficiency and resistance of porous aluminium filter material were calculated,and the preliminary design of porous aluminium filter and its components was completed.Through the above research,the porous aluminum filter dust removal system of porous aluminum filter material preparation,surface modification and its properties,normal temperature and normal temperature mechanical properties,gas permeability coefficient,filter material structure and filter design were preliminarily formed.It lays a foundation for the application of porous aluminum filter materials in the field of gas-solid filtration at normal-high temperature.