The invention relates to a method for extracting gold and silver, comprising the following steps of: mixing pulp by using barren solution after flotation concentrate, adding
sodium cyanide and
lime,
grinding ores in a ball
grinding mill, grading the ores discharged by the ball
grinding mill by using a swirler, and returning the ball grinding
machine for regrinding the graded ores and settled sand; washing and concentrating the graded overflow by using a thickener, leaching a bottom flow, continuously adding the
sodium cyanide and the
lime for leaching, and washing
cyanogen slag to be sold as
sulfur concentrate; forming a precious solution by using overflow water of the thickener, purifying the precious solution, deoxidizing the precious solution, replacing gold and silver by
zinc powder to form the barren solution, and making the barren solution return as flotation concentrate pulp-mixing water and washing water. The method for extracting gold and silver is characterized in that in an ore-
grinding process,
oxygen is introduced to the ball
grinding mill, the concentration of the
oxygen in the ball
grinding mill is improved with the enlargement (destroy of a coated film) of the ore grain grinding degree and the explosion of gold and silver grains, the
concentration ratio of a
cyanogen radical to the
oxygen approaches to the optimum value in a milling-strengthening process, the concentration of the oxygen during grinding and leaching is kept above 5 mg / L, the [CN] is kept at 2,500-3,500 mg / L, and the
concentration ratio of the [CN] to the [O] is 500-700. The method realizes
oxygen enrichment cyaniding, leaching and ore grinding by filling
pure oxygen in the ball
grinding mill and improves the
leaching rate of gold and silver ore grinding, thereby improving the gold and silver cyaniding
recovery rate, reducing the grade of
cyanogen slag and obtaining a better economic technical index.