NOVEL TWO-STAGE FLOTATION COLUMN DESIGN AND TESTING

MECHANIZED MINING METHODS THAT INCREASE THE PROPORTION OF FINE COAL BEING FED TO CLEANING PLANTS HAVE CAUSED INCREASEDEMPHASIS TO BE PLACED ON IMPROVING THE EFFICIENCY OF FINE COAL PROCESSING EQUIPMENT, PARTICULARLY FROTH FLOTATION CIRCUITS. THE ADVANCED PHYSICAL COAL CLEANING TECHNOLOGIES BEING EVALUATED BY DOE AND EPRI ALSO INVOLVE FINE TO EXTREMELY FINE GRINDING OF THE COAL TO IMPROVE LIBERATION OFASH AND SULFUR. THEREFORE, DEVELOPMENT OF EFFICIENT FINE COAL CLEANING EQUIPMENT AND PROCESSES IS ALSO CRITICAL FOR COMMERCIALIZATION OF THOSE ADVANCED TECHNOLOGIES. THIS PROPOSAL OUTLINES A PROJECT FOR CONSTRUCTION AND TESTING OF A NOVEL TWO-STAGE FLOTATION COLUMN DEVELOPED BY PTI FOR FINECOAL CLEANING APPLICATIONS. THE PROTOTYPE DESIGN WILL BE SIMILAR TO CONVENTIONAL COLUMN DESIGNS IN TERMS OF GEOMETRY,AIR BUBBLE GENERATION AND FROTH WASHING CAPABILITIES. THE UNIQUE ASPECTS WILL BE THE FEED SLURRY ADDITION APPROACH AND THE DUAL CYLINDER CONSTRUCTION DESIGNED TO IMPROVE FROTHDRAINAGE AND REDUCE ENTRAINMENT OF CLAYS INTO THE FROTH PRODUCT. THE PHASE I PROJECT WILL INCLUDE PRELIMINARY TESTING OF THE TWO-STAGE COLUMN TO DETERMINE THE OPTIMUM OPERATING CONDITIONS AND FINAL DESIGN OF THE PROTOTYPE COLUMN. THE PROTOTYPE COLUMN WILL THEN BE TESTED HEAD-TO-HEAD AGAINST A CONVENTIONAL SINGLE-STAGE COLUMN WITH THE SAME GEOMETRY, AIR BUBBLE GENERATION METHOD AND FROTH HEIGHT CONTROLS TO DETERMINE IF THE TWO-STAGE DESIGN APPROACH ACTUALLY IMPROVESEFFICIENCY FOR A NUMBER OF DIFFERENT COAL FEEDS. ANY FUTUREPHASE II PROJECTS WOULD INVOLVE SCALE-UP OF THE COLUMN TO COMMERCIAL SIZE AND RESEARCH INTO THE NECESSARY AIR BUBBLE GENERATION, FROTH WASHING AND FROTH LEVEL CONTROL COMPONENTSREQUIRED TO PROVIDE THE OPTIMUM PERFORMANCE.