1 CSTB, Comfort Health Direction, Aero-Contaminants and Biological Agents Division, France.
2 Aix-Marseille University, CNRS, Centrale Marseille, France.
Waste Manag Res. 2019 Sep;37(9):914-924. doi: 10.1177/0734242X19859426. Epub 2019 Jul 17.
The asbestos-containing waste management is a public health topic for countries which have used this mineral. Treatment of chrysotile (white asbestos), a phyllosilicate from serpentine, crocidolite (blue asbestos, first results on this kind of asbestos), one of the five asbestos varieties of amphibole family and asbestos-containing waste conversion process is proposed by using hydrothermal treatment in supercritical water. All samples were treated in an Inconel Batch Reactor. The treatment durations range is from 1 to 6 hours, temperatures range is from 400°C to 750°C, mass concentration range is from 0.02 to 170 mg. mL and pressures are higher than 23 MPa. Ultrapure water is used for sample preparation. This ultrapure water is used to monitor mineral leaching on the aqueous phase and to avoid particle cross-contamination. Transmission electron microscopy analyses were carried out to check the presence or not of asbestos phase. According to these analyses, the best conditions of conversion were 1 hour and 0.02 mg. mL for chrysotile, 3 hours and 0.02 mg. mL for crocidolite and 1 hour and 20 mg. mL for asbestos-containing waste, at = 750°C. Supercritical water conditions were maintained during the whole treatment. The X-ray diffraction showed that the main phases present after treatments were riebeckite and magnetite (crocidolite), forsterite and enstatite (chrysotile), and calcite, spurrite and gehlenite (asbestos-containing waste). Finally, a scanning electron microscopy analysis was performed to monitor morphological fibre change. The elongated structure, partially fragmented, was found in all samples.
含石棉废物管理是使用过这种矿物的国家的一个公共卫生议题。采用超临界水的水热法处理温石棉（蛇纹石中的层状硅酸盐，对这种石棉的首批研究结果）、青石棉（蓝石棉，属于角闪石族的五种石棉之一）和含石棉废物，提出了对青石棉（蓝石棉）和含石棉废物转化过程的处理方法。所有样品均在 Inconel 间歇式反应堆中进行处理。处理时间范围为 1 至 6 小时，温度范围为 400°C 至 750°C，质量浓度范围为 0.02 至 170 mg·mL 和压力均高于 23 MPa。超纯水用于样品制备。该超纯水用于监测水相中的矿物浸出情况，避免颗粒交叉污染。进行透射电子显微镜分析以检查是否存在石棉相。根据这些分析，温石棉的最佳转化条件为 1 小时和 0.02 mg·mL，青石棉的最佳转化条件为 3 小时和 0.02 mg·mL，含石棉废物的最佳转化条件为 1 小时和 20 mg·mL，在 750°C。整个处理过程中都保持超临界水条件。X 射线衍射表明，处理后存在的主要相为霓辉石和磁铁矿（青石棉）、镁橄榄石和顽火辉石（温石棉）以及方解石、硅钙钡石和钙铝榴石（含石棉废物）。最后，进行了扫描电子显微镜分析以监测纤维形貌变化。在所有样品中都发现了结构拉长、部分破碎的纤维。
