Research On The Bubble Forming Rules And Its Experiment With Dissolved Air Method

Air flotation is a technology which can use micro bubbles to separate other phases andwater, so it is widely used in environmental, mining, chemical industry, etc. Small diameter,density, uniformity, good bubble is the key to the high eiffciency separation effect of airlfotation. The pressure dissolved air method is a way of generated bubbles in the air flotation,its principle is dissolved air water through depressurization and energy dissipation, dissolvedgas molecules will quickly gathered into ifne, uniform size, quantity，number of air bubbles.So research on the theoretical of bubbles generated after pressure dissolved air water dissolvedgases and pressure relief has very important significance to how to generate more tiny airbubbles and effective use of initial energy.Researched on the process of the gas dissolution and bubble generated with method ofdissolved air, discusses the relationship between the initial pressure, pressure release rate andthe generated bubble size. First studied the gas dissolving mechanism, gas dissolved in waterhas two forms. In these two forms, when temperature than50。C, hydration iflling effect isgreater than the clearance, temperature is more less than50°C, the gap iflling effect is greaterthan the hydration; Secondly, studied the process of system pressure converted into free energyin the process of bubbles generated with dissolved air method, the smaller the diameter ofbubble is generated, the more the change of the free energy will, that the more pressure canalso be required; Finally, studies the key equipment-generating bubbles dissolved air release(TS)，the influence of the Angle of the release to stress release rate, a different release Angle isobtained by flow ifeld simulation, stress release rate also is different，the release Angle，thegreater the release rate.Based on the theoretical research，The study developed a dissolved air bubbles generatedtest irg which consist of water and air supply system, the pressure of dissolved gas system,pressure relief system and image acquisition system, completed the bubble generation processexperimental study. By changing the initial dissolved air pressure and stress release rate，therelease rate is constant, the diameter of bubble is generated will be decreased with the increaseof initial pressure, and the pressure increases to a certain value, the diameter of the bubble isno longer reduce; The initial pressure is constant, the bubble diameter increases with the increase of release rate, the release rate is smaller than a certain value, increase the diameter ofbubble is smaller.Through the above theoretical and expeirmental research, can get when the initialpressure is0.4MPa, with the increase of pressure, the diameter of bubble is no longer reduce;When the release angle is less than45the size of the bubble diameter increase is smaller. Sothe more ideal conditions of generate tiny bubbles dissolved air method is: the initial pressureis0.4MPa，and release angles is no more than45°, the bubble size at this time is the mostsubtle, its size can maintain at about30|im.