The invention discloses a high-temperature steam in-situ
coal leaching
hydrogen production and waste residue in-situ
metal mining method, and belongs to the technical field of
coal underground in-situ
hydrogen production and resource comprehensive utilization. The method comprises the following steps: firstly, injecting high-temperature and high-pressure steam into a target
coal seam through a ground or underground
drill hole, enabling the steam to seep in a coal seam fracture network subjected to fracturing transformation by utilizing pumping and injecting
pressure difference, and carrying out
pyrolysis and gasification reaction with coal to generate a
combustible gas-liquid mixture taking
hydrogen as a main component; after the product is extracted and separated, hydrogen and other resources are recycled, and
coke is retained in underground supporting
overburden strata. And then, according to the porous waste residue ore deposit rich in
metal formed after gasification, adaptive in-situ leaching liquid is injected through original or newly-arranged
drill holes, and valuable
metal in the porous waste residue ore deposit is dissolved and recycled. According to the invention, direct ignition and
oxygen injection
combustion of traditional underground gasification are avoided, the problems of easy
flameout, unstable gas production, low heat value and the like are solved, and meanwhile, clean
hydrogen production of coal and green collaborative mining of associated metal resources are realized.