Study On Ammonia Nitrogen Wastewater Treatment And Ammonia Resource Recovery Technology In Rare Earth

There are reserves of rare earth resources in our country. Using ammonium sulfate leachingrare earth, the south ion adsorption type rare earth enterprises discharge a large amount ofammonium nitrogen wastewater every year. Ammonium nitrogen wastewater has detrimentaleffects on the natural environment and human body. In this paper, the rare earth ammoniumnitrogen wastewater has been treated by using the combination methods of air stripping and ionexchange adsorption, the purpose is to meet the "rare earth industrial pollutant dischargestandard"(GB26451-2011), recovery of ammonium nitrogen in the wastewater, realize resourcerecycling.Through orthogonal experiments, every factor and parameter for every process wasoptimized. Air stripping experiment mainly concluded the following results:â‘ Air stripping is suitable for treating high concentration of ammonium nitrogenwastewater. After being treated by two steps air stripping, the ammonium concentration reducesfrom1000mg/L to100mg/L. The order of influencing factor about air stripping waspH>temperature> gas-liquid ratio.â‘¡The alkaline air stripped from the wastewater can beabsorbed by sulfuric acid, which can be used as leaching reagent and return to use or produceammonium sulfate fertilizer.Na-D113ion exchange resin was used to deeply treat ammonium nitrogen wastewater. Theion exchange adsorption experimental results were:â‘ The influencing factor about ion exchange adsorption was resin dose>contacttime>initial ammonium nitrogen concentration.â‘¡HCl solution is a good desorptional reagentfor ammonium nitrogen. The solution after desorption was acidity water containing higherdensity ammonium nitrogen, which can be used as leaching reagent for returning to production.â‘¢Because of the complexity composition of the actual wastewater, the removal of ammoniumnitrogen in actual wastewater and simulated wastewater has a difference. After treated theindicators meet the "rare earth industrial pollutant discharge standard"(GB26451-2011) aboutdirect discharge of water pollutants concentration limit for new enterprise.â‘£The adsorptionalmechanism was coexist with physical adsorption and chemical adsorption (ion exchange). Theadsorptional equilibrium data fitted well for the Langmuir model. Adsorption is mainly happenedon surface active area of resin. Secondary dynamic equation can better describe the adsorptionalbehavior of ammonium nitrogen by Na-D113resin. According to the fitted results of movingboundary model, adsorption phase was the control stage for ion exchange adsorption process.