“碱-矿渣-粉煤灰-煅烧高岭土”水合陶瓷固化模拟中放α废液

Immobilization of Simulated Medium Level Alpha Liquid Waste in "Alkali-Slag-Fly ash-Calcined Kaolin" Hydroceramics

以钕和铈作为放射性铀和钚的模拟核素,采用碱激发和水热法制备了模拟中放α废液"碱-矿渣-粉煤灰-煅烧高岭土"水合陶瓷固化体。研究了固化体的结构组成、力学性能、抗侵蚀性和化学稳定性。结果表明:固化体的主要晶相组成为方沸石和NaPl沸石;在水热条件下,固化体中掺入模拟中放α废液后有利于沸石晶相的形成。抗压强度测试表明,固化体中废物包容量达到40%左右时仍能满足水泥固化体抗压强度的要求。固化体经硫酸盐介质和地下水侵蚀28 d后,其抗压强度损失较少,外观没有裂纹和龟裂,说明固化体具有较好的的抗硫酸盐和地下水侵蚀性能。另外,静态浸出测试结果表明,Nd和Ce的浸出率在10^(-8)~10^(-6)cm/d范围,说明固化体具有优良的化学稳定性。

The 'alkali-activated slag-fly ash-calcined kaolin' hydroceramic(ASFCH) used for solidifying simulated medium level alpha liquid waste(S-MLALW) was prepared by alkaline activation and hydrothermal methods with neodymium and cerium as simulated radioactive nuclides of uranium and plutonium.The phase composition,mechanical strength,corrosion resistance and chemical stability of ASFCH waste forms were investigated.The results show that the main crystalline phase components of ASFCH waste forms are analcime and zeolite NaPl.The introduction of S-MLALW is contributed to the formation of zeolite phases in ASFCH waste form.According to the results of the compressive strength tests,the strength of ASFCH waste form still meets the requirement of cemented waste form when the waste package capacity is 40%.Moreover,the compressive strength of ASFCH waste forms decreases slightly after corrosion by sulphate solution and simulated ground water for 28 d.Also,there are no cracks and fractures appeared on the ASFCH waste forms.It is indicated that ASFCH waste form has a preferable corrosion resistance to sulphate solution and ground water.Besides,the leaching rates of neodymium and cerium are in the range of 10^(-8)-10^(-6) cm/d,showing that ASFCH waste forms for solidifying S-MLALW also possesses superior chemical stability.