Static Experimental Research On Air Stripping Of Ammoniac Wastewater In Rare-Earch Industry

With the fast development of the industry of rare-earth, the factory of rare-earth seguential product and run, however, the lot of ammonia in rare-earth wastewater not only results in the ammonia salt loss, but also causes the serious environmental pollution. Therefore, it is necessary for sustainable development of ecological environment to seek the valid processing method of ammonia in rare-earth wastewater. At the same time, it is the active demand for protecting water resources our country.In this thesis, the auther researches for the ammonia nitrogen wastewater in the rare-earth factory of Baotou. Based on the characteristic of high hardness, the high concentration and an indefinitely large number wastewater quantity, the static experiment is carried on. Before considering the operational cost, the plan for the treatment wastewater and the economic rational experimental parameter are definited with experiment.Wastewater ammonium chloride is treatmented through the intersecting experiment, the thesis comes to conclusion that the primary and secondary parameters order of the influencing factor about blowing is pH, air tripping temperature, air tripping time and gas-liquid ratio. The conclusion are drawn with single factor that the economic practical operation conditioning is pH 12, air tripping temperature 30℃, air tripping time 3 hours, the gas-liquid ratio 6000 and under this condition, the ammoniac concentration reduce from12017.6 mg/L to 336mg/L and removal rate can reach over 97.2 %. At one time, the wastewater can approximately reclaim ammoniums sulphate.Wastewater ammonium sulphate is pretreated before air tripping with the method of calcium hydroxide. The hardness of wastewater reduce from 235.58mmol/L to 20.53mmol/L and ammonia nitrogen reduce from 11193.3mg/L to 6347mg/L and the concentration of SO42-reduce from 51842.4mg/L to 2164.76mg/L. Under the condition of pH12, air tripping temperature 30℃, air tripping time 3h, the gas-liquid ratio 6000, ammonia nitrogen of wastewater ammonium sulphate reduce from 6347mg/L to 169mg/L and removal rate can reach over 97.3 %. Under the condition of pH12, temperature of water 30℃, air tripping time 2h, the gas-liquid ratio 3500, ammonia nitrogen of the wastewater reduce from 169mg/L to 23.3mg/L. The removal rate can reach over 86.2% and the treatment method satisfies standard for discharge. At one time, the wastewater can approximately reclaim ammoniums sulphate.The conclusions that are got by the captive test of ammonium chloride's wastewater and ammonium sulfate's wastewater offer an important reference frame for the reference frame's design of the ammonia nitrogen wastewater. At the same time, the conclusions have guiding significance for the ammonia nitrogen wastewater's pollution.