Online slag analysis utilising contact-free microwave technology
Slags chemical stability due to erosion when deposited, geotechnical properties when used for road applications, and slag structure have been investigated using leaching tests, cooling rate studies, and microwave technology. The geotechnical properties were investigated using BOF slag, melted and tapped during controlled cooling rate conditions. An average cooling rate between 15 to 20 °C/min during the first 10 minutes directly after tapping provided a final product having the properties required. The investigation shows that an increase in the cooling rate damages the geotechnical properties, especially related to Micro-Deval and Los-Angeles characteristics. Leaching tests using EAF and ladle slags were performed, using a flow-through test and the standard batch test DIN 38414-S4. In flow-through tests, leaching levels are below 1.2 g/kg (Ca), 0.06 g/kg (Mg) and 0.6 mg/kg for other elements. Leachates obtained with DIN 38414-S4 present higher leaching values; however, they are below 18 g/kg (Ca), 0.06 g/kg (Mg) and 10 mg/kg (other elements). Microwave technology was used to investigate solid and liquid slag, synthetic and production slags, as to their dielectric properties, expressed as the refractive index, and relate these to the chemical structure. However, no explicit correlation between the refractive index and the slag composition, on a statistically significant level, could presently be established. Industrial trials performed on a ladle showed that it is possible to measure the slag thickness; however, the results are very much dependent on the slag condition, and whether rough surfaces and/or not dissolved slag formers appear in the slag.
Bibliographic Reference: EUR 21787 EN (2005), 71 pp. Euro: 15
Availability: http://bookshop.europa.eu/is-bin/INTERSHOP.enfinity/WFS/EU-Bookshop-Site/en_GB/-/EUR/ViewPublication-Start?PublicationKey=KINA21787 (Catalogue Number: KI-NA-21787-EN-S)
ISBN: ISBN 92-79-00080-2
Record Number: 200618435 / Last updated on: 2005-12-15
Original language: en
Available languages: en