SBM Vertical Mill

Vertical Mill Wear Rates When Grinding Slag

As granulated blastfurnace slag has very abrasive properties the grinding parts (M-rollers and table liners) have to be hardfaced. The wear occurs mainly at the outer diameter of the M-roller. The S-rollers usually do not wear. Extent of wear is influenced by the quality and type of grinding elements, the fineness of products and the moisture content of the feed materials. Hardfaced grinding elements with high carbide content have a lower wear rate than that of cast metals with a high chromium content and thus extend the service lives of the M-rollers and table liners. Right table compares the set up and hardfacing times of two mills. The specific wear rate for GGBS is below 5g/t in the case of produced Blaine figures from 3500 to 5400cm²/g according to EN 196-6. The specific wear rate based on long-term-experience is between 4 to 7g/t of product. The number of welding heads influences the required welding time. The hardfacing in nearly all cases is carried out inside the mill. If carried out regularly the tyres can be hardfaced many times. There are tyres in operation which have been hardfaced more than 20 times and have ground more than 2Mt of GGBS.