Detoxification of industrial asbestos waste by low-temperature heating in a vacuum

Abstract

Industrial asbestos waste such as asbestos cement board, sprayed crocidolite and sprayed amosite was heated in a vacuum. The detoxification conditions were then established in reference to JIS A 1481:2006 and JIS K 3850-1:2006. When asbestos cement board was heated at 700°C for 1 h, detoxification of the cement board was completed. On the other hand, in the case of amphibolic asbestos waste, such as sprayed crocidolite and sprayed amosite, was heated, a phase-contrast microscope analysis was not applicable for identification of asbestos heated at more than 500°C. According to XRD analysis, crocidolite was eliminated by heating at 800°C for 3 h. Furthermore, amosite was not detected after heating at 700°C for 3 h. Finally, the grindability of heated amphibolic asbestos was investigated. When sprayed crocidolite was heated at 900°C for 3 h and then ground with a mortar for 300 s, the crushed grains had a length of less than 5 μm and an aspect ratio of 3. In addition, when sprayed amosite was heated at 1000°C for 3 h and then ground, the crushed grains had a length of less than 5 μm and an aspect ratio of 3.