A large Canadian metallurgical coal plant sought help in maximising fine coal recovery, minimising moisture and optimising the performance of its coal flotation circuit. It also wanted to improve the environmental footprint by replacing diesel as a collector in their coal flotation process. Another local company has been fined in excess of $100,000 for polluting the environment, and imprisonment had been involved. Having extensive knowledge of the customer’s operations, and after a thorough evaluation that included both laboratory and in-plant flotation testing, it was determined that Nalco’s NALFLOTE 9899 flotation reagent could help the customer meet its goals.
NALFLOTE 9899 is an alternative to using fuel oil (a diesel collector). Its active chemistry is derived from renewable resources. Diesel on the other hand is derived from petroleum oil, with documented negative impact on the environment.
The customer had been dosing diesel collector at 3,600 cc/min. With NALFLOTE 9899, it only needed to dose at 1,400 cc/min. Moreover, the customer replaced the frother reagent (methyl isobutyl carbinol) with Nalco’s NAFLOTE 9897. The result was an increase in metallurgical coal tonnage of 14 t/h. And the ash content of the recovered coal decreased by 5%.
In addition, Nalco reports “the NALFLOTE program is more forgiving – it adapts to different coal seams mined. Under the diesel collector program, dosage can increase as high as 4,500 cc/min if the coal seam is of poorer quality.
Ancillary benefits observed from implementing the program include a decrease in the solids loading on the fine refuse circuit and corresponding decrease in the cost of water clarification as the result of reduced flocculant consumption. Total benefit of the NALFLOTE program is estimated to be $25 million.
“The successful NALFLOTE integration at this site improved the customer’s productivity and profitability while decreasing the environmental footprint. Further, the success enjoyed at this site has resulted in plant management recommending that sister plants also evaluate the NALFLOTE alternative. So far four plants have adopted this new approach, adding millions of dollars in annual clean coal recovery.
