Storage And Conveying Of Wet Powder Materials

Mechanical properties of the powder particles have a great impact on the storageand transport, the mechanical properties of powder particles is directly related to itswater content. The object of this study include powdered calcium carbonate, calciumcarbide slag and fly ash in the paper.It is investigated that the interal friction coefficientvarious water content by means of triaxial compression tests for the three powder; It isinvestigated that the friction coefficient between the powder within various watercontent and the wall material different roughness by means of direct shear tests;Varying port dimater,roughness of wall and water content of material,the mass flue ofdischarge and its stability is investigated.The results show that:(1) With the increase of water content, friction coefficient of three wet powderpresent decreasing trend; cohesion of fly ash and carbide slag present increase withwater content increase, With the increase of water content, cohesion of calciumcarbonate show increase firstly and then decrease.(2) To the same wall tmaterial,the impact of water content to wall frictioncoefficient isnot obvious; The larger the surface roughness of the wall material, the larger the wallfriction coefficient of the powder particles, the more difficult to flow. To the wetpowder,the adhesion resistance on carbon steel is greater than its on stainless steel andpolymer plates.(3) To the perspex sheet with small roughness,with the water content increase, theaverage velocity of the fly ash will reduce, the stability of the material will bedeteriorate. Increases the diameter of discharge port, can accelerate the flow, but willresult deterioration to the stability of the flow, when the discharge port diameter is 40mm, the moisture content7%of fly ash appear the phenomenon of blocking material;the larger the surface roughness, the smaller the falling speed of the material, the worststability of the fall. To the sand paper with bigger roughness,when the diameter ofdischarge port is40mm, fly ash with water content of4.5%and7%occurs blockingmaterial.When the diameter of the discharge port is increased to60mm, the watercontent4.5%of the fly ash is free to fall under gravity, the water content7%of thematerial still occurs blocking material. When the diameter of the discharge port isincreased to80mm, all powder can fall free.According to the results, when handling wet powder in engineering production,smooth surface material were used as a bin liner, and by increasing the discharge portdiameter, the impact of the liquid bridge force could be mitigated and made the processof falling stable. To ensuring the stability of the discharge process, the discharge portdiameter should not be too large, otherwise the material will produce the phenomenonof collapse, leading to the production of discontinuities.