The effects of sodium dodecyl sulfate (SDS) and the mixture of SDS and crystal seed kaolin on mine gas hydrate formation and CH4 separation were investigated to improve the dynamic conditions of mine gas hydrate formation.The pressure-temperature-time (p-T-t) curves for low concentration mine gas in hydrate formation were obtained in four test systems.The test systems are SDS solution with mass fraction of 10.34% and mixture of SDS with kaolin with three different mass fractions of 1.47%

5.64% and 8.23%

respectively.CH4 concentrations in separation residues were analyzed by using gas chromatography.The results showed that the induction time was shortened and the hydrate formation rates increased by adding SDS and the mixture of SDS and kaolin; the shortest induction time and the largest mean formation rate in four systems

were 72 min and 5.261×10-6 m3·h-1

respectively; the concentrations of CH4 increased by 12.40% through 20.61% after first separation; the highest separation concentration of CH4 increased up to 58.41% in mixture system of SDS and kaolin

with fractal growth of mine gas hydrate existing in the systems.