The 1980s saw the beginning of a shift in the cement industry. Slowly and steadily, cement producers began to adopt vertical roller mills (VRMs) for cement grinding instead of ball mills. Fast forward to today, and the VRM, with its superior grinding efficiency and low power consumption, is the industry standard, according to FLSmidth.
Since FLSmidth's initial OKTM Mill installation in 1982 through to the end of 2018, customers have bought a total of 184 mills, confirming FLSmidth’s place as the industry leader for cement and slag grinding.
Raw materials grinding was added to the OK Mill’s résumé in 2017. Following the launch of this flagship VRM, three new OK Raw Mills were sold in 2018 – a strong indication that cement producers are favoring FLSmidth’s modular mill design for both raw materials and cement grinding. The flexibility of the modular design is a key driver of its success. It uses the same core grinding parts in raw and cement mills, in multiple mill sizes, greatly reducing the capital investment for spare parts in a plant.
FLSmidth has supplied VRMs to 67 countries around the world since the OK Mill launched in 1982. In the last two years alone, OK Mills have been sold in Indonesia, the Philippines, Algeria, Turkey, United Kingdom, Pakistan, Nigeria, Kenya, Peru, Cuba, India, Nepal, Algeria and Egypt.
Particularly in South Asia and Africa, where large-capacity plants are installed, cement producers choose single big mills to take advantage of the lower installation costs associated with a single mill versus multiple smaller units. Perhaps the most impressive example of this is at Shah Cement in Bangladesh, where an 81-6 OK Mill, the world’s largest vertical roller mill for cement grinding, was inaugurated in 2018 – featuring six rollers and a 8.1-metre diameter grinding table.
FLSmidth has supplied OK Mills with grinding tables ranging between 2.8m and 8.1m in diameter. The number one selling mill size is the OK 56-4 Mill, which is right in the middle of the available size range.
Reliable production, low total cost of ownership and industry-leading energy efficiency are just some of the OK Mill’s key characteristics. Its modular design with parts commonality across applications and sizes enhances these benefits.