Study On The RE Ceria Composite Glass Fining Agent

The output of the glass in china ranks first in the world. At present, arsenic trioxide is still vastly used as one of the most effective agent by china's glass industry. However, arsenic trioxide is highly toxic, 0.06 grams can be deadly. While used as fining agent, some arsenic trioxide permeate into glass and residue on the form of As2O3 and As2O5. In the glass melting system, at a high temperature about 1/3 arsenic trioxide volatile emits to the atmosphere and pollutes the environment. The rest arsenic trioxide residue in glass products. Arsenic may be dissolved from glass, when glass is full with liquid drugs, alcohol, beverages and so on, which would be a great threat to the user's physical security. Nowadays, some developed countries have restrictions on arsenic glass products to enter the national market.In order to make the glass industry of China develop healthily and in the view of protecting environment and human health, the replace of non-toxic compound fining agent to arsenic trioxide fining agent during glass producing process, will not only bring great economic benefits, but also greater social and environmental benefits. The study of drug-free fining agent is important for realistic meaning.The glass on the Na2O-CaO-SiO2 system were used as basic components in this paper, At high temperature, the glass was melted, and finally got glass materials. This study focused on compound rare-earth ceria fining agent. Small amount of cerium oxide, sodium nitrate and sulphate were added to basic components of glass separately, with the help of magnifier and polarization microscope, finding the best fining agent. The result shows that single rare-earth ceria can not come to the best effection. The fining agent of rare-earth ceria with proper amount sodium nitrate will get a good result. If add proper amount sulfate and fluorites to this fining agent, a better result will be got. compared with traditional fining agent arsenic trioxide, determined the best content of rare-earth ceria fining agent is CeO2 0.04%,NaNO3 2.05%,Na2SO4 0.1% ,CaF2 1.67%.Through exploration the mechanism of glass fining agent, ceria rare earth compound used in the glass is "gradually" to clarify theory, step by step decomposed, when the glass melting, decomposition temperature is from 1220℃to 1450℃, relay clarification, clarify capacity has been in a strong state, the effection is better than the traditional fining agent.Based on testing of UV-visible spectrum, the introduce of rare earth ceria reduce the UV transmittance, the glass can absorb UV. Further experiments found that added proper amount titanium dioxide to rare-earth ceria can make the glass into gold.