Evaluation of Dry Cobbing - LTV

Abstract

To remain competitive, the taconite companies in Minnesota must explore every opportunity to reduce costs and improve overall plant operations. Magnetic cobbing of rod mill feed is generally recognized as having the potential to reduce operating costs because of the rejection of low grade material ahead of the primary mill. Implementation of this technology requires testing that will accurately predict metallurgical performance, weight rejection and magnetic iron recovery. The savings in grinding energy that derive from rejecting a coarse, low grading product before primary milling have to carry the additional operation costs for dry cobbing and the cost of installation. Magnetic cobbing tests on minus 3/4-inch material have always been shown to have a beneficial effect on downstream processing. In-plant dry cobbing tests have indicated a 5% increase in plant throughput with comparable iron recovery. Use of dry cobbing at even coarser sizes may be beneficial to some operations. The Coleraine Minerals Research Laboratory (CMRL) has conducted extensive research on the dry cobbing of taconite materials. This study was to determine the feasibility of dry cobbing on LTV crushed ore at minus 3-inch, minus 1-inch, and 5/8-inch and their liberation characteristics.