Research On Leaching Of Heavy Metals In Sludge By Impulse Ultrasound And Hydrodynamic Cavitation

In recent years, much attention has been paid to heavy metal solid waste treatmentresearch, the acid and alkali leaching method because of its simple processing operation, littleenvironmental risk and large-scale application feasibility of higher advantages and has beenwidely used. But, this kind of method in the treatment of low heavy metal content, solidwastes recycling value is not high, you need to join excessive leaching agent and appear lesssuitable. So to develop a can handle low heavy metal content methods of solid waste, to solvethe problem of heavy metal pollution has realistic significance.Caused by ultrasonic and hydrodynamic cavitation can produce local high speed microjet, the liquid jet flow can erosive parcel layer on the surface of the solid particles, eliminateobstacle of the mass transfer process, activate the passivated layer, speed up the solid liquidphase reaction and mass transfer and reaction speed, so some of the researchers at home andabroad to strengthen ultrasonic hydrodynamic cavitation strengthening process of heavy metalleaching reaction and sludge and waste water treatment process in a lot of research, the resultshave proved that the cavitation effect can not only shorten the leaching and processing time,reducing the potion, can greatly improve the leaching rate and the treatment effect. However,ultrasound assisted leaching generally consume much energy, energy efficiency is low, andthe space of the cavitation range is small and difficult to scale. Hydrodynamic cavitation,although high energy efficiency, cavitation intensity is low, ideal auxiliary leaching effect isnot easy to get. Therefore, it is necessary to combine two cavitation methods to creat theeffect of high efficiency and low energy consumption.This thesis mainly studies the ultrasonic cavitation and hydrodynamic cavitationcoordination treatment effect of low content of heavy metal sludge, as well as the influencingfactors of these two kinds of cavitation effect. Including: pH、thickness of the orifice plate、aperture diameter of the orifice plate、upstream and downstream pressure、temperature、ultrasonic power、impulse ultrasound, to explore the best reaction conditions.The innovation of this research are that:(1)we established the coordination withhydrodynamic cavitation coupled pulse ultrasonic assisted leaching of heavy metals, themethod has high efficiency and low energy consumption of the cavitation effect;(2)We applythis method to comprehensive treatment of heavy metal pollutants from the source toeliminate heavy metal pollution of these solid waste.