高放废液的玻璃固化及固化体的浸出行为与发展情况

对高放废液固化体的种类硼硅酸盐玻璃固化体的特点及结构进行了叙述，对玻璃固化体的浸出行为及其研究的发展情况进行概括，也谈及了我国在高放废注玻璃固化研究的状况。     

模拟高放废物碱矿渣水泥固化体抗冲击性能的研究

研究了模拟高放废物碱矿渣水泥固化体的抗冲击性能。实验结果表明：固化体的固化工艺对其抗冲击性能有很大影响，水泥固化体的抗冲击性能优于玻璃固化体。     

MoO3对玄武岩玻璃结构及性能的影响

三氧化钼在硼硅酸盐玻璃系统中的溶解度非常低,其在核废料玻璃中的过量存在可导致易溶“黄相”的形成。本实验以天然玄武岩制备的玄武岩玻璃为基体,掺入不同含量的MoO₃制备玻璃固化体。采用X射线衍射分析、场发射扫描电子显微镜等测试手段对不同条件制备的玻璃固化体进行表征,研究了MoO₃添加量对玻璃固化体微观形貌、理化性能、化学稳定性的影响。结果表明:MoO₃的大量引入将使玄武岩玻璃析出CaMoO₄。随着MoO₃添加量增加,玻璃固化体Tg下降,密度上升。其钼酸盐最大溶解度为5.5%(质量分数),高于硼硅酸盐玻璃系统,此时玻璃化转变温度、密度分别为619℃、2.70 g/cm²。玄武岩玻璃富含铝,通过对硼硅酸盐玻璃和玄武岩玻璃成分的对比分析,这是其具有优异钼酸盐溶解度的主要原因,玄武岩玻璃固化体28天的浸出液Mo浸出率为8.5×10^-6 g/(m²·d),与广泛使用的硼硅酸盐玻璃相当。     

水热法制得硼硅酸盐含水玻璃导电性的研究

以硼硅酸盐玻璃为原料 ,采用水热热压 (HHP)工艺制备了具有高电导性的含水玻璃 ,制得玻璃的电导率在 2 5℃时达 1.7× 10 -4 S.cm-1,在 15 0℃时达 1.2×10 -2 S .cm-1,已达到日本超导电玻璃电导率的数量级。并用IR、XRD、LCR等手段分析了玻璃的水化产物、水化过程中的物相和水化机理。同时研究了所制得含水玻璃固化体的导电机理及水化温度对固化体导电性影响。结果表明水在固化体中以分子水和结晶水为存在形式 ,≡SiOLi+H2 O ≡SiOH +Li+ +OH-,H2 O +≡Si-O -Si≡ ≡SiOH +≡SiO-,OH-+≡Si-O -Si≡ SiOH +≡SiO-为其水化机理反应式。该含水玻璃以离子导电为主 ,并且增大 -OH浓度或升高水化温度都有利于提高含水玻璃导电性     

颜料对紫外光固化环氧丙烯酸酯涂料的影响

研制了一种新型彩色艺术玻璃涂料———紫外光固化环氧丙烯酸酯彩色涂料,研究了辐射时间、颜料的种类、用量及其复合方式等因素对涂膜的固化速度、硬度和附着力等性能的影响。     

钻井废弃泥浆固化研究

通过对废弃泥浆固化室内实验 ,研究了影响固化效果的湿度、温度、pH值等影响因素 ,分析研究固化体微观结构 ,探讨了固化剂的作用机理。     

温度对模拟高放玻璃固化体显微结构和抗浸出性能的影响

以模拟北山地下水为浸泡剂,采用静态浸出试验法(MCC-1),研究了温度(40～150℃)对模拟高放废液硼硅酸盐玻璃固化体显微结构和抗浸出性能的影响.结果表明:玻璃固化体浸泡42 d后,在90℃及以上温度出现了蜂窝状的页硅酸盐和铝硅酸盐矿物,在150℃还新生成了白色板状BaSO4晶体;Si、B、Cs和U元素的归一化浸出率(LR)在28 d后趋于平稳,且随着温度升高浸出率逐渐升高;基于B元素浸出速率的表观活化能约为27.8 kJ/mol;玻璃固化体在90℃模拟地下水浸泡28 d后的LRSi、LRB、LRCs、LRU分别为1.45×10-1、1.39×10-1、2.48×10-1、1.3×10-1g/(m2·d).     

钙钛锆石玻璃陶瓷体的晶化和抗浸出性能

以SiO2、A12O3、B2O3、CaO、TiO2和ZrO2为原料,加入3％CeO2（质量分数,下同）作为模拟核素,利用熔融法制备钙钛锆石基玻璃陶瓷体,对含锕系元素的放射性废物进行固化处置。通过X射线衍射仪和场发射扫描电子显微镜等对热处理后玻璃陶瓷体进行表征。以电感耦合等离子体质谱测试玻璃陶瓷体抗浸出性能。结果表明：在晶化温度为1050℃,B203掺量为12．5％时,玻璃陶瓷体中低质量分数的TiO2和ZrO2更易参与生成钙钛锆石晶体,但固化体中仍有其他晶相存在;在同样晶化温度下,B203掺量为8．33％时对玻璃陶瓷体形成钙钛锆石单一晶相较为有利,且具有较好的抗浸出性能,其中Ce在产品一致性测试法下元素标准化浸出率7d后维持在10^-6数量级,固化效果明显。     

钻井废弃泥浆固化研究

通过对废弃泥浆固化室内实验,研究了影响固化效果的湿度、温度、pH值等影响因素,分析研究固化体微观结构,探讨了固化剂的作用机理。     

锕系核素污染沙土的铝热剂SHS固化模拟实验

为探索对锕系核素污染沙土进行玻璃或陶瓷固化的有效途径,采用了铝热剂自蔓延高温合成(SHS)固化的模拟实验.主要进行了铝热剂粉末SHS固化的原理分析、模拟物质的选择、单质铁中模拟物质的含量、固化体中模拟物质浸出率的实验等.结果表明,固化体中模拟元素铈、铒的浸出率为10~(-3)～10~(-5) g·m~(-2)·d~(-1)量级;X射线衍射分析、扫描电镜观察发现,固化体中含有模拟元素铈、铒的硅酸盐晶体,晶体周围分布着大量玻璃体;单质铁相中模拟元素含量极低.用铝热剂可以固化锕系核素污染的沙土.     

Leaching behavior of fly ash-waste glass and fly ash-slag-waste glass-based geopolymers

The leaching behavior of contaminants in the fly ash/waste glass or fly ash/blast furnace slag/waste glass-based geopolymers was investigated through surface area analysis and leaching tests. Spent fluorescent lamps classified as hazardous waste due to their specific contaminant contents were used as a source of waste glass. The results from semi-dynamic leaching tests showed that the mobility of contaminants increases as the amount of waste glass added to the synthesis mixture increases. These results are consistent with those obtained from the surface area analysis. However, the comparative analysis of mobility of contaminants between types of activated mixtures highlighted a different trend of mobility of contaminants to that of pore size distributions. Therefore, the leaching behavior of contaminants suggests that their immobilization in the activated mixtures might occur by both physical and chemical mechanisms. Also, it was emphasized that waste glass is not compliant with respect to its leachable Hg content, and that Hg and Pb exhibit high mobility in the geopolymers with high amount of waste glass added to the synthesis mixtures.     

Effect of temperature on leaching alkali metal ions from waste glass powder used as an additive to portland cement

Leaching is considered as a means of reducing the alkalinity of glass powders produced from waste container glass and employed as additives to portland cement. The temperature of a leaching agent is established to be a key factor affecting the efficiency of the procedure. Also, for optimal leaching, the glass powder needs to be exposed only once to hot (close to boiling) water—a leaching agent—and only for a short period.     

Inhibition of Nuclear Waste Glass Leaching by Chemisorption

The durability of a simulated nuclear waste containment glass was investigated by static leaching tests in six types of leaching containers. Glass corrosion in lead containers was reduced by more than two orders of magnitude from that measured in Teflon, whereas aluminum containers resulted in nearly a one order of magnitude reduction. Relatively minor effects on glass leaching were measured in copper, tin, and titanium containers. The results have strong implications concerning the choice of materials in possible waste package designs.     

硼硅酸盐玻璃浸出前后结构变化的研究

硼硅酸盐玻璃作为最具工业化应用前景的高放射性废物的固化基材,其中的放射性核素主要以浸出方式进入生物圈。本工作采用了MCC-1静态浸泡法对在90 ℃去离子水中浸泡28 d后的硼硅酸盐玻璃的浸出行为进行了研究。借助电感耦合等离子体发射光谱(ICP-OES)、傅里叶红外光谱(FTIR)、拉曼光谱(Raman)以及掠入射X射线衍射(GIXRD)等方法对玻璃的浸出性能及微观结构进行研究。此外,还使用了扫描电镜观测了浸出样品的截面。FTIR、Raman及GIXRD结果表明,浸出后,样品表层中的Si-O-Si结构明显增多,而硼结构单元则消失,表层的微观结构与熔融石英的结构较为相似。此外,在扫描电镜中观察到浸出7 d后的样品表面出现腐蚀层,同时在玻璃基底和腐蚀层中间出现裂隙,由此导致了浸出表面积的增加,从而最终引起浸出7 d时元素归一化标准浸出率的异常增大。     

Study on the leaching behavior of salt waste forms prepared by using zeolite and lime glass

When the reaction of salt and zeolite was used to minimize the free salt in waste forms (r = 0.1), Cs showed the lowest leaching rate, 1.015 × 10⁻¹ g/m² d. Because alkali chloride is chemically stable, the reaction that alkali elements become components of glass does not happen and thus the leach resistance of the waste form solidified with soda glass was not much different from that solidified with borosilicate glass. The crystalline phase containing Cl was sodalite, but the tendency that Cs exists prior to sodalite phase was not confirmed. From a result of a long-term leaching, the predicted leaching fraction of Cs in 900 days was as high as 5.13%, but that of Sr was as low as 0.24%. The leaching experiment with a varying pH showed the major nuclides such as Cs, Sr, and Li in salt waste had different leaching characteristics each other.     

Adsorption of Pb and Cd in rice husk and their immobilization in porous glass-ceramic structures

Rice husk, an agricultural waste, is abundantly available in many countries such as China, India, Brazil, US, and South East Asia. Despite the massive production of rice husk, it is mainly disposed to landfill. In this work, utilization of rice husk for a potential waste-water treatment is evaluated, along with subsequent encapsulation of the adsorbed heavy metals (Pb and Cd) inside a porous glass-ceramic. Vitrified bottom ash (another source of waste) was mixed with foaming agents in dif- ferent weight ratios (40:60, 50:50, and 60:40) to prepare a glass matrix for encapsulation of Pb-/Cd-loaded rice husk. It was shown that using 40 wt% vitrified bottom ash with 60 wt% foaming agents leads to a foam glass with the best pore size distribution. Therefore, this batch was further mixed with 70 volume% (5 wt%) heavy metal-loaded rice husk and was heat-treated at 750°C for 3 hours. The final glass-ceramic porous structure was char acterized using SEM, XRD, compression test, and it was shown that it is safe to be used as it passes the EN12457-2 leaching test.     

Characterization of glassy materials for immobilization of radioactive waste with a high iron oxide content

The influence of the content of oxides in the simulated high-level wastes on the phase composition, the structure, and the water resistance of borosilicate-based glassy materials for immobilization is investigated. An increase in the waste oxide content from 45 to 65 wt % leads to an increase in the fraction of the crystalline phase of the magnetite-type spinel from 3–5 to 20–22 vol %. The glassy materials are characterized by a low leaching rate of the main waste components in water. A considerable increase in the leaching rate of sodium ions and, to a lesser extent, aluminum and uranium ions is observed for the glassy materials containing waste oxides at a content of 55 wt % and more due to the depolymerization of the structural glass network. Under the same conditions, the leaching rate of iron does not increase noticeably because of the high resistance of the iron-containing spinel to water.     

Preferential Dissolution of an Intergranular Amorphous Phase in a Nuclear Waste Ceramic

A leaching experiment is conducted on thin transmission electron microscope samples of a tailored polyphase nuclear waste ceramic. The results demonstrate that the intergranular noncrystalline phase is preferentially dissolved, which calls attention to the possibly detrimental role of any intergranular glass in ceramics designed to immobilize nuclear waste.     

Effect of Gamma Radiation on Glass Leaching

Significant increases in the leaching rate of PNL 76–68, a complex simulated nuclear waste glass, were observed to occur in the presence of gamma radiation. Some of the enhanced leaching is due to the generation of nitric acid from air radiolysis in the leach vessel. Nitric acid appears to preferentially attack zinc and lanthanides, both of which normally build up on the surface of the glass when leached in nonacidic solutions. Increased rates were also found for samples irradiated while leaching but with air excluded to eliminate nitric acid formation, indicating that water radiolysis products may also be important. Samples irradiated prior to leaching showed dissolution rates indistinguishable from those of unirradiated specimens.     

Crystalline-Phase Formation in Hot Isostatic Pressing of Nuclear Waste Ceramics with High Zirconia Content

Ceramic forms with a significant glass phase have been prepared from Zr-rich simulated Idaho Chemical Processing Plant high-level nuclear waste by hot isostatic pressing of redox-controlled waste and chemical additive calcines. Crystalline-phase formation in the ceramics is a function of the waste loading, additives, and consolidation temperature. Actinide host phases are controlled by silica-zirconia crystal chemistry; the composition of the amorphous phase dominates the leaching behavior. Two phase assemblages—one consisting of CaF₂, ZrO₂, ZrSiO₄, and glass, the second of CaF₂, ZrO₂, YNaSiO₄, ZrSiO₄, and glass—showed leach resistance superior to melter-processed borosilicate glass forms for uranium and, at waste loadings >80 wt%, offer a factor of up to 3.2 times greater volume reduction. The presence of the designed glass phase in the waste forms makes them more flexible to variations in waste composition and lowers the required hot isostatic pressing temperature for consolidation as compared with polycrystalline waste ceramics, while maintaining the actinide leach resistance of the crystalline phases.