Fundamental and formation aspects of slag freeze linings : a review

Abstract

Traditionally, pyrometallurgical reactors are lined on the inside with refractory materials. Some of the high-temperature phases are aggressive towards the furnace lining, requiring periodic repair or replacement of the lining. The freeze-lining concept, however, involves the deliberate formation of a layer of solidified bath material on the inner walls of the reactor lining. This self-repairing freeze lining can protect the reactor lining from corrosive attack by the liquid phases. Hence, this can be a solution for the periodically required lining replacement. However, the existing somewhat limited knowledge is mostly based on primary metal production systems, and future applications (with secondary feed materials for recycling purposes) will require more fundamental knowledge on the influencing parameters. This review collects the current knowledge regarding freeze linings. The various methods used to experimentally investigate freeze-lining phenomena experimentally are discussed. Then the generally accepted mechanism controlling freeze-lining formation is presented, followed by a listing of various influencing parameters. Next, the various mathematical models and approaches used to describe freeze-lining thickness are introduced. The remaining challenges conclude this review.