A Study on Evaluation of Ignition Dangers of Hazardous Wastes

目前还没有确定适当的方法来调查危险废物的点火危险。在这项研究中，我们进行了一项基本实验，以创建并提出一种测试方法，用于确定可燃固体废物的危险性，其着火危险性可与“联合国建议，第4.1类”（橙皮书）中引用的危险性相媲美。采用以下物质作为试验材料：金属粉末；塑料，这是消防法案指定的可燃材料；可燃固体（闪点< 40ºC）：四甲基氧基钛、三氧烷等；可燃固体（联合国建议）：萘、多聚甲醛等；以及常见的有机物质：蒽、锯末等。将这些物质与铝粉和纤维素按不同比例混合制备模拟废物。危险性的测量是按照《消防法》规定的小气体闪燃试验和Seta闭杯闪点试验，以及联合国建议书第4.1类规定的燃速试验进行的。同时，采用数字量热计、高压差示热平衡、氧指数法进行了危险性判定的验证试验。通过对上述各种试验数据的仔细分析，我们认为采用改进型氧指数法是最合适的方法。结果表明，在固定氧浓度为21 vol%的辅助燃烧气体（O_2/N_2）下，被试物质在10秒内被点燃，继续燃烧，在90秒内与小气体火焰接触，存在着火危险。

No appropriate method has yet been established to investigate ignition dangers of hazardous wastes. We have undertaken in this study a basic experiment in order to create and propose a test method for the determination of the dangers of the wastes of combustible solids with the ignition dangerousness comparable to those cited in "the United Nations Recommendations, Class 4.1" (Orange Book).The following substances were used as the test materials : metallic powders ; plastics, which are the combustible materials designated by the Fire Service Act ; ignitable solids (the flash point < 40ﾟC) : tetramethoxytitanium, trioxane, and so on ; combustible solids ( the United Nations Recommendations) : naphthalene, paraformaldehyde, and so on ; and common organic materials : anthracene, sawdust, and so on. The simulated wastes were prepared by mixing these substances with aluminium powder and cellulose in various proportions.The measurment of the dangers was carried out in conformity to the small gas flash ignition test and the Seta closed cup flash point test prescribed by Fire Service Act, and the burning rate test provided by the United Nations Recommendations, Class 4.1. At the same time, the confirmatory test has been carried out for the determination of dangerousness by using digital calorimeter, high-pressure differential thermal balance, and Oxygen Index Method.Careful analysys of the data obtained from various tests mentioned above led us to recognize the method using the improved type of Oxygen Index Method to be the most relevant one. As a consequence, we conclude that there exists the ignition danger when substance under testing ignited within 10 seconds, continued burning, and terminated within 90 seconds by the contact with the small gas flame under a fixed 21 vol% oxygen concentration in support burning gas (O_2/N_2).