The mechanism of adding sodium carboxymethyl cellulose(CMC) to improve the strength of hematite ore and coal briquettes was investigated by infrared spectroscopy(IRS),X-ray photoelectron spectroscopy(XPS) and contact angle measurements.It is found that -OH and -COOH in CMC chemically absorb at the surface of hematite ore and reduce the hydrophilic character of ore particles,while hydrocarbon chains in CMC bond on the surface of coal and reduce the hydrophobic character of coal particles.Hematite ore and coa...