硼硅酸盐玻璃成分对硫酸钡热稳定性的影响

Effect of Borosilicate Glass Composition on the Thermal Stability of Barium Sulfate

研究了硼硅酸盐玻璃主要成分(SiO2、Na2O、B2O3)对硫酸钡(BaSO4)热稳定性的影响,分析BaSO4分别与SiO2、Na2O、B2O3的混合物在不同温度(800~1 200℃)煅烧后的物相组成、显微结构、硫含量和拉曼光谱。结果表明:当BaSO4:SiO2摩尔比为7.5:92.5 (样品A)时,在温度低于1 200℃煅烧后其物相均为BaSO4和SiO2,温度达到1 200℃时出现了少量硅钡石(BaSi2O5)相;当BaSO4:SiO2:Na2O为7:86:7 (样品B)时,在800℃煅烧后即出现了少量BaSi2O5相,当温度达到1200℃时样品主要物相为BaSi2O5和方石英,硫含量明显减少;当BaSO4:SiO2:Na2O:B2O3为5.5:67.5:6.5:21.5 (样品C)时,在800~1 200℃均为BaSO4和SiO2,在1 200℃保温2h后,BaSO4和SiO2的衍射峰基本消失。低熔点的Na2O和B2O3的引入促进了BaSO4的分解,在1 200℃煅烧后,样品A、B、C中SO4四面体的拉曼特征峰依次减弱。

The influence of main components of borosilicate glass(SiO2、Na2 O、B2 O3) on the thermal stability of barium sulfate(BaSO4) was studied,and the phase composition,microstructure,sulfur content and Raman spectrum of BaSO4 calcined with mixtures of SiO2,Na2 O and B2 O3 at different temperatures(800~1 200℃),were analyzed.The results show that when the molar ratio of BaSO4:SiO2 is 7.5:92.5(sample A),after calcining lower than 1 200℃,the phases are BaSO4 and SiO2;and a small amount of BaSi2 O5 phase appears when the calcination temperature reaches 1 200℃.When BaSO4:SiO2:Na2 O is 7:86:7(sample B),a small amount of BaSi2 O5 phase appears after calcining at 800℃.When the temperature reaches 1 200℃,the main phase of the sample is BaSi2 O5 and cristobalite,and the sulfur content is significantly reduced.When BaSO4:SiO2:Na2 O:B2 O3 is 5.5:67.5:6.5:21.5(sample C),BaSO4 and SiO2 phase appear at 800~1 200℃,and the diffraction peaks of BaSO4 and SiO2 almost absent after being kept at 1 200℃for 2 h.Moreover,the introduction of Na2 O and B2 O3 with low melting point can promote the decomposition of BaSO4,after calcinating at1 200℃,the Raman characteristic peak of SO4 tetrahedron in sample A,B and C decreased successively.