Study On Radon Reduction Effect And Mechanism Of New Mixed Materials

Radon pollution is the main problem faced in the treatment of uranium tailings ponds.Covering method is one of the most effective treatment methods,and covering material is an important factor affecting the effect of covering method for radon control.Therefore,this paper takes uranium tailings as the research object to study the radon reduction effect and mechanism of three new mixed materials of laterite with high-strength gypsum,laterite with bamboo carbon particles,and laterite with montmorillonite powder.The main research contents and conclusions of the paper are as follows:(1)After adding high-strength gypsum,bamboo carbon particles and montmorillonite powder to laterite,the radon reduction effect was enhanced.In addition,as the content of the added material increases,the gap in the radon reduction effect narrows,and the radon reduction efficiency does not improve significantly after the thickness exceeds 6cm.(2)When the mixed material formed by adding bamboo carbon particles to laterite was used as the covering layer,the moisture content of the covering layer increased,and the radon reduction efficiency first decreased and then increased.When the water content is less than 18%,the decrease is slow.When the water content increases from 18% to 27%,the radon reduction efficiency drops sharply to the minimum,which is53.7%,and the decrease rate reaches 34.9%.(3)When the mixed material formed by adding montmorillonite powder to laterite is used as the covering layer,the moisture content of the covering layer increases,and the radon reduction efficiency increases rapidly.When the moisture content is 18%,the radon reduction efficiency is 90.6%,and the subsequent improvement is small.(4)The radon reduction mechanism of the mixed material formed by adding high-strength gypsum to laterite is that its coagulation and hardening speed is very fast.During the process of changing from a plastic slurry to a hard stone-like body,it can bond the loose and granular laterite into a whole in a short time.The cover layer gels from a loose state to a relatively dense state,thereby inhibiting the exhalation release of radon.The radon reduction mechanism of the mixed material formed by adding bamboo carbon particles to laterite is that it is loose and porous,and has strong adsorption,which can adsorb the radon atoms in the diffusion movement,prevent the exhalation and release of radon atoms,and then play a role in reducing radon.The radon reduction mechanism of the mixed material formed by adding montmorillonite powder to laterite is that its particle size is very small,which can be filled into the pores of laterite particles,and rapidly and violently expands when absorbing water,forming a dense covering layer,thereby effectively inhibiting the exhalation and release of radon.(5)After comparative analysis,the mixed material formed by adding montmorillonite powder to laterite has the best covering effect of radon reduction,the mixed material formed by adding bamboo carbon particles has the second best covering effect,and the mixed material formed by adding high-strength gypsum has the worst effect of covering radon reduction.