| Along with the energy-saving projects carring out all over the world, the production and usage of fluorescent lamps increased year by year. Meantime, how to deal with those spent fluorescent lamps has become an urgent problem. If effective treatment can be put forward for the problem, it not only can solve a series of environmental problems about fluorescent lamps, but also makes most of fluorescent materials recovery and recycling, which appears to be an effective way to ease some tension resources problem.This paper briefly introduced some information related to the fluorescent lamps, summarized the handling ways and study progress of spent fluorescent lamps at home and abroad. On this basis, it proposed two effective ways to dispose the waste fluorescent lamps with the purpose harmless and recycling.At first the waste fluorescent lamps were broken under the acetone solution using the"spot energy effecf"of ultrasound that could effectively desorb mercury. In this way, it effectively captured mercury vapor and enabled majority of adsorpt mercury to be desorbed. The test was carried out by the single factor experiment .Some effect factors were analyzed in the test, such as acetone solution concentration (C),solid-liquid ratio (S/L), ultrasonic time (t), etc.When C=30%, S/L = 238.16g/L, t=30 min, the system reached the optimum condition, and the amount of mercury removed from each fluorescent lamp got to 5.028 mg.The acetone solution containing mercury was treated by a joint process comprised of sulfide depositing- flocculating - activated carbon adsorpting The experimental results showed that when pH = 2.0, 275ml wastewater with initial mercury concentration 13.79mg/L,the dosage of sodium sulfide,polyaluminum chloride and activated carbon were 4 mg,80mg and 25mg, mercury removal rate reached 99.8%, Mercury concentration in filtrate was reduced to 26.82 ug /L,which is lower than pollutant emission standards in our country.The discarded rare earth trichromatic phosphor was quantitatively analyzed by X-ray fluorescence spectrometry. The result showed that it included rare earth oxide content as high as 26.936%. The test used 2.0g phosphor everytime, for inspecting the optimum conditions in hydrochloric acid leaching. When hydrochloric acid concentration C=4.0mol/L, solid-liquid ratio L/S=10ml/g, stirring intensity R=600rpm/min, reaction temperature T = 60℃, H2O2 =0.4ml, reaction time t = 60min is the best.Under these conditions,the same quality of abandoned phosphor can be leached 502.033mg, leaching rate was 93.19%.In addition, the test also used ammonia-oxalic acid to deposite the rare earth in the leaching solution and to recover rare earth oxides through high-temperature calcination. The best conditions for depositing rare earth was (1+1) ammonia: 75 ml/L; 50g/L solution of oxalic acid:100ml/L; aging time:3-4 hours.The leaching solution of simulated rare earth phosphors's deposition rate was 89.13%.Besides,the waste of rare earth phosphors leaching solution's deposition rate was further improved, which rises to 94.98%.At last, the elementary study about the calcined rare-earth productor was carried out. It was analyzed and characterized by using XRD, and scanning electron microscopy (SEM). Test results showed that the producor was mainly consisted of high purity cubic crystal system Y2O3, for its morphology was mainly lamellar particles. |
