Department of Nuclear and Quantum Engineering, KAIST, Daejeon, 34141, Republic of Korea.
Department of Nuclear and Quantum Engineering, KAIST, Daejeon, 34141, Republic of Korea; Chemistry Division, Pakistan Institute of Nuclear Science and Technology, P.O. Nilore, Islamabad, Pakistan.
J Hazard Mater. 2019 Jul 15;374:228-237. doi: 10.1016/j.jhazmat.2019.04.038. Epub 2019 Apr 13.
An efficient method for the consolidation of cobalt (Co(II)) adsorbed calcium hydroxyapatite was investigated to develop a simplified route for decontamination of the coolant system of nuclear power plants and direct immobilization of as-spent adsorbent. Calcium hydroxyapatite nano-powder synthesized by a wet precipitation method was used as an adsorbent and 94% Co(II) surrogate removal from simulated water was measured. The as-spent adsorbent was sintered at 200 °C, a temperature significantly lower than conventional sintering temperatures (900-1300 °C) for hydroxyapatite, under a uniaxial pressure of 500 MPa for 10 min. The relative density after the cold sintering was >97% and sintered samples displayed good compressive strength (175 MPa). The normalized leaching rate of the Co(II) was measured as per ASTM-C1285 standard and found to be 2.5 × 10 g/m/day. ANSI/ANS-16.1 test procedure was used to analyze the leachability of the sintered matrices and the measured leaching index value was 6.5. Thus, the use of pure calcium hydroxyapatite nano-powder as adsorbent and its cold sintering offers a mean by which radioactive waste form can be processed in an environment friendly manner.
研究了一种将吸附钴（Co(II)）的羟基磷灰石进行固结的有效方法，以开发一种简化的核电厂冷却剂系统去污方法，并直接将即用型吸附剂进行固定。采用湿沉淀法合成的羟基磷灰石纳米粉末用作吸附剂，测量了从模拟水中去除 94%Co(II)的效果。将用过的吸附剂在 200°C 下进行冷烧结，烧结温度明显低于羟基磷灰石的常规烧结温度（900-1300°C），在 500MPa 的单轴压力下烧结 10 分钟。冷烧结后的相对密度>97%，烧结样品显示出良好的抗压强度（175MPa）。根据 ASTM-C1285 标准测量 Co(II)的归一化浸出率，发现为 2.5×10 g/m/day。采用 ANSI/ANS-16.1 测试程序分析烧结基体的浸出性，测量的浸出指数值为 6.5。因此，使用纯的羟基磷灰石纳米粉末作为吸附剂并进行冷烧结为以环保的方式处理放射性废物提供了一种途径。
