Study on bed resistance of dense fixed bed adsorption tower

Dense fixed bed adsorption tower is a common adsorption equipment in in-situ leaching mine. The bed resistance will increase with the adsorption process, leading to the decrease of equipment processing capacity and the increase of energy consumption. The bed resistance is mainly composed of two parts, one is the resistance of the bed itself, and the other is the bed interception in the slurry resistance. In this paper, the pressure drop （the resistance of the bed itself） of the resin bed under four kinds of empty tower linear speed is measured. The analysis results show that the pressure drop of resin bed is proportional to the empty tower linear speed, it’s almost a straight linear. Then, the changes of the bed resistance under the adsorption conditions of 35 m/h, 45 m/h and 60 m/h respectively at the empty tower line speed are obtained by the test. The sample analysis shows that the bed resistance will continue to increase with the adsorption, and the higher the empty tower line speed, the faster the bed resistance increase. The sample analysis of the resin bed at the end of adsorption found that the blockage existed in the upper part of the resin bed within 0.3 m, and mainly concentrated on the surface of the resin bed. By backwashing the resin in this area and controlling a certain flow rate, most of the flocculation could be washed out, while the resin don’t flow out with it. After the backwashing, the bed resistance could basically recover to the level of the initial adsorption. This paper aims to study the main factors affecting bed resistance and propose measures to reduce bed resistance.