Laterite-nickel ore combination leaching process

The invention relates to a laterite-nickel ore combination leaching process, which comprises that: limonite type laterite-nickel ore is subjected to crushing grading, and then is added with concentrated sulfuric acid to carry out primary stage normal pressure stirring self-heating leaching, serpentine type laterite-nickel ore is subjected to crushing grinding, the obtained serpentine type laterite-nickel ore and the primary stage leached ore magma are concurrently conveyed to a pressure kettle, and serpentine is leached by using the primary stage normal pressure leaching residual acid and the acid produced through iron precipitation in the pressure kettle, or mixing type laterite-nickel ore is subjected to grading, the obtained fine particle-grade ore is added with concentrated sulfuric acid to carry out primary stage normal pressure stirring leaching, ore on the sieve is subjected to crushing grinding, the grinded ore and the primary stage leached ore magma are concurrently conveyed to a pressure kettle, and coarse particle-grade ore leaching is performed by using the primary stage normal pressure leaching residual acid and the acid produced through iron precipitation in the pressure kettle. According to the invention, the process has characteristics of no special requirements on ore types and grades, wide raw material adaptability, investment reduction, energy consumption reduction, production cost reduction, and simple process, wherein the Ni recovery rate and the Co recovery rate of the whole process of the present invention are respectively more than 90% and 88%, and are higher than the Ni recovery rate and the Co recovery rate of the treatment method in the existing non-high-pressure acid leaching technology.