Chlorine Salt-assisted Thermal Desorption Of Mercury Contaminated Soils Experimental Research

Mercury is the only liquid metal under normal temperature, mercury pollution has hightoxicity, persistence and bioaccumulation has become one of the environmental issues ofconcern at home and abroadbut the production. Mercury is known as the only heavy metal"POPs" And has a property of cross-contamination. Global legally binding mercuryconvention of UNEP proposed "Minamata Convention" has been successfully signedprimarily to serve the purpose of reducing mercury on human health and environmental risks.Article comparative advantages and disadvantages of existing mercury control technology ofcontaminated sites, and on the basis of the existing research on the theory of chloride. Bythermal desorption chemical conditioning synergistic research chloride effects of mercury insoil for mercury removal, using high-temperature tube furnace. By mercury removal, TGAand XRD experiments mercury speciation analysis.Using high temperature tube furnace, by chemical control method to study mercury soilchlorine salt together thermal desorption effect on mercury removal rate. From the mercuryremoval rate, the thermogravimetric test and XRD analysis of mercury form three aspects areanalyzed Adding chlorine salt on mercury removal rate in different temperature conditionspromoting effect is obvious. At230℃with ferric chloride, magnesium chloride and calciumchloride removal of mercury66.2%increase, respectively,49.3%and15.8%. Three types ofchloride salt for the promotion of mercury thermal desorption order: FeCl3> MgCl2> CaCl2.Add ferric chloride under300℃，25min mercury in96.1~96.2%, the removal rate ofchange of mercury removal efficiency of68.3%. Ferric chloride as additive is the bestcondition of200℃for25min. Thermogravimetric experiment results show that the carriergas less volatile effect on the mercury, wet chlorine dosing weightlessness curve at lowtemperature is more obvious; According to the result of the furnace tail crystal XRD patternanalysis, under the condition of low temperature, with the addition of chlorine salt promotemercury samples to mercuric chloride, enhances the removal of mercury.TGA experiments analysis of several mercury compounds weightlessness temperaturerange, while comparing the effects of carrier gas for thermal desorption. By contrast the purechemical reagents cast wet and dry salt chlorination dosing effects, the results showed thatwet salt chlorination cast downward trend evident in the low-temperature phase.According tothe sample and the result of the furnace tail crystal XRD pattern analysis, under the conditionof low temperature, with the addition of chlorine salt promote mercury samples to mercuric chloride, enhances the removal of mercury. By mercury removal, TGA, XRD, HSC chemistryand ion chromatography to verified from different angles for mercury chloride promotedvolatile. Chloride was added to promote the conversion of mercury and its compounds toform HgCl2. Due to the effect of chlorine salt achieved a higher removal rate in lowtemperature; at the same time shorten the interval of reaching stability state of the mercuryremoval rate.