Roll-Press Briquetting Turns Waste Lime Fines into Valuable Product

Background:

The Linwood Mining and Minerals Corporation’s Buffalo Plant mines approximately two millions tons of limestone per year.

Adding a new rotary kiln more than doubled lime production capacity at Linwood Mining and Minerals Corporation’s Buffalo plant. But it also raised the problem of what to do with a greatly increased output of fines.

Challenge:

Linwood realized landfilling waste fines at rates of up to 100 tons/day wouldn’t be a good long-term solution. According to Assistant Lime Plant Manager Dennis Jones, “the minute we started planning the kiln expansion, we knew we’d get into trouble with the amount of fine output.”

Solution:

Linwood previously considered briquetting the fines for sale, but it wasn’t a viable option because of the relatively small amount left over. Adding the new kiln finally made it feasible. Jeff Dahl, Plant Manager, said “briquetting always looked like the only way to reclaim fines in this quantity, and the only company we saw that could supply the kind of equipment we needed was K.R. KOMAREK Inc.”

Linwood sent several barrels of calcined fines to KOMAREK’s dedicated research lab for testing on special laboratory versions of KOMAREK’s production machines. Tests confirmed that the material formed good briquettes, with no need for binders.

Guided by the evaluation results, KOMAREK proposed a roll-press briquetter engineered to produce an oval-shaped briquette at throughputs of up to 10,000 lbs (4,500 Kg) per hour. The briquettes were formed with two counter-rotating rolls, vertically opposed and fed from one side by a horizontal infeed screw. The machine also featured a cantilevered design with rolls mounted outside one end of the machine, which allows for quicker, easier roll changes – another KOMAREK recommendation because the abrasiveness of lime requires periodic replacement of worn-out rolls.

Results:

Dahl explained the primary goal with the briquetting solution was to reduce the cost of waste. “If 20 percent of our material comes through as fines and gets dumped, then we’re throwing away 20 percent of the cost of mining the stone, crushing, screening, handling and calcining it. That makes those fines too valuable to end up on a landfill. We figure this system paid for itself within a year or so.”

With the help of KOMAREK’s automated roll press briquetter, Linwood not only dodged the landfill scenario, but more importantly, gained a way to keep new fines in the product stream at full value.