Reserch On Stabilization Of Heavy Metal Sludge By Thick Ferrite Process

With the continuous development of industry, heavy metal pollution has become a majorenvironmental problems. Heavy metal pollution has cumulative toxic effects on theenvironment, and has caused a lot of pollution incidents, such as Minamata disease, Itai-itaidisease and so on. For the treatment of heavy metal pollution is mainly concentrated in areasof heavy metal wastewater treatment, heavy metals precipitation sludge generated aftertreatment is often little processing. This heavy metal sludge leaked heavy metal intoenvironment due to the changing of natural conditions, causing secondary pollution. The mainpurpose of this experiment is to be treated for heavy metal sludge of heavy metal wastewatertreatment process, through thick ferrite technology to convert it to ferrite precipitation whichhas good stability, so as to effectively prevent the leakage of heavy metals in sludge andgenerating a processed recycled product.In this study, processing conditions is researched by three ways of drug dosing situation,and by anti-solvent experiments under extreme conditions to carry out experimental study onthe stability of the product. Heavy metal sludge drug dosings use Fe3+, Fe2+/Fe3+mixeddosing, and Fe2+/H2O2mixed dosing three kinds of ways. After the experiment can be seen,the drug dosing of Fe3+had the maximum anti-solvent rate, and made less generation ferrite.The drug dosing of Fe2+/Fe3+and Fe2+/H2O2had the lower anti-solvent rate, and made moregeneration ferrite. In comparison, the best way of drug dosing is Fe2+/Fe3+mixed dosing, andhad the more stable treatment effect than the drug dosing of Fe2+/H2O2mixed dosing.Sludge treatment for heavy metal sludge is divided into simulated and actual sludgetreatment experiments. Simulation sludge treatment experiments is researched by thetreatment of Ni(OH)2precipitate and Cr(OH)3precipitate. This experiment is studied of drugdosage, pH, reaction time, reaction temperature, and aging time to determine the optimalreaction conditions. Experiments can be seen, the best results can be obtained at pH9, andmaximum amount of heavy metals changed into the ferrite. Through experimental observation,the reaction results become better when the reaction time extended and the reactiontemperature rise. Combined with the economic cost analysis, the optimal results is gottenwhen the reaction time is4h, and the reaction temperature is75℃. For the majorThe actual sludge treatment experiments select the electrolysis sludge of a nickelcompany. Through the sludge analysis, nickel and chromium are the main metallic elements,and contains copper, cadmium, lead, zinc and other metal elements. With reference to theSimulation sludge treatment experiments, the optimal results is gotten at pH9, and otherreaction conditions were the same as simulated sludge treatment experiments. Under thisconditions, the stabilization of actual sludge can be gotten, and other heavy metal elements can be stabilized at the same time. For the major chemical element, the anti-solvent rate of thechromium is5%~7%, and the anti-solvent rate of the nickel is33~35%.The resulting processed products are tested for toxicity leaching experiment andproperties detection by X-ray diffraction (XRD), field emission scanning electron microscopyand vibrating sample magnetometer. Through the tests can be seen, the majority of theproducts is NiFe2O4and FeCr2O4, with the good crystallinity and good magnetic properties.Finally, used by subsequent processing, heavy metal sludge has realized the stabilization,harmless and recycling treatment.