Energy recovery from concentrate in waste gasification fine slag by clean flotation assisted by waste oil collector

The feasibility of energy recovery from flotation concentrate with waste oil as collector from gasification fine slag was verified. The calorific value of flotation concentrate with different size was studied. Firstly, size composition, particle morphology and phase composition of gasification slag were analyzed. Subsequently, the flotation characteristics and kinetics of narrow size slag particle were revealed. Scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) results show that the gasification slag is porous and rough, and the surface hydrophobicity is weak, resulting in the massive consumption of collector. As collector, waste oil and diesel oil have similar flotation effect. Loss on ignition (LOI) of concentrate decreases from 42.28% to 34.19% and the recovery increases from 34.09% to 38.85% when the waste oil collector dosage increases from 4 to 14 kg/t. With the decrease of particle size, recovery increases from 39.04% to 50.93%. Traditional flotation kinetic models can describe the flotation characteristics of gasification slag accurately. Finally, calorific value of flotation concentrates with different size range from 5.81 to 19.01 MJ/ kg, which illustrate the flotation concentrate has potential to be used as fuel. Therefore, the goal of treating waste (gasification slag) with waste (waste oil) is achieved.