Experimental Study On Solidifying/Stabilizing Tailings With Hydantoin Epoxy Resin Composite Clay

The tailings produced by mining and beneficiation pose a great threat to the surrounding environment because of its low utilization rate and long-term exposure to the surface environment.Solidification/stabilization has been widely used in the treatment of tailings.However,the use of conventional cement and geopolymers as curing agents will consume energy and exhaust gas and cause serious environmental pollution.In this paper,hydantoin epoxy resin and red clay are used as raw materials to solidify/stabilize tailings.Through unconfined compressive strength test,TCLP leaching test,flexible wall infiltration leaching test and dry wet cycle test,the mechanical properties,environmental compatibility and durability of solidified bodies with different mixing ratios are studied,and the relevant curing mechanism is explained.By means of X-ray diffraction（XRD）and scanning electron microscope（SEM）,the microstructure evolution law of solidified body after different mixing ratio and acid rain leaching is analyzed,and the proportion optimization scheme is put forward based on the test results.The main conclusions are as follows:（1）When the content of hydantoin epoxy resin is less than 10%,the compressive strength of solidified body increases with the increase of the content of red clay;When the content of hydantoin epoxy resin is 10%,the compressive strength of solidified body first increases and decreases with the increase of the content of red clay,and there is an optimal mixing ratio between them.At the same time,it is found that the correlation between the mixing ratio and the failure strain of solidified body is not obvious.（2）When the content of hydantoin epoxy resin is 10%,the Cu²⁺leaching concentration decreases significantly with the increase of the content of red clay,and the Cu²⁺leaching concentration of solidified body with different mixing ratio meets the identification standard of hazardous waste.（3）Under the action of rainwater infiltration leaching at different p H,the permeability coefficients of solidified bodies with different mixing ratios are in the order of 10^-5～10^-6 cm/s,the concentration of Cu²⁺in leachate is less than 100 mg/L,and the fixation rate of Cu²⁺is greater than56%,which has a good curing effect on Cu²⁺.（4）Under the action of dry-wet cycle,with the increase of dry wet cycle times,the damage degree of solidified body samples with different mixing ratio gradually deepens,the mass loss rate gradually increases,and the compressive strength and failure strain of solidified body also decrease with the increase of dry-wet cycle times.（5）When the content of hydantoin epoxy resin is 10%,when the content of red clay increases from 0%to 5%,the"granular mosaic cementation"structure is gradually formed in the solidified body,and the cementation degree is significantly enhanced.When the red clay increases to 30%,the aggregate looseness in the solidified body increases.After acid rain infiltration leaching,the montmorillonite minerals in the solidified body decrease,the cementitious substances decrease,and the amorphous substances,pores and fractures increase,forming the dominant channel of acid rain infiltration.（6）Based on the test results,it is determined that 10%hydantoin epoxy resin and 5%red clay are the preferred materials for solidifying/stabilizing tailings.