Siderite roasting and dry sorting method

The invention provides a siderite roasting and dry sorting method comprising a reduction roasting step and a dry sorting step. The method specifically comprises the steps of: mixing a raw ore of siderite and bituminous coal, then, roasting in a downdraught way, and introducing nitrogen gas for cooling after the roasting is ended, thus obtaining roasted ore; firstly, crudely crushing the roasted ore, then, sieving the roasted ore by using a 10mm sieve, crushing the roasted ore with the size being larger than 10 mm again, and carrying out dry sorting on screen underflows to obtain a magnetic mineral product, wherein the dry sorting refers to sorting for the screen underflows by using a wind power and magnetic force comprehensive force field; then, finely crushing the magnetic mineral product, then, sieving the magnetic mineral product (which is obtained through the dry sorting) by using a 3mm sieve, crushing the magnetic mineral product with the size being larger than 3mm again, and carrying out dry magnetic separation on the screen underflows to obtain magnetic concentrate. The magnetic concentrate has the ferrum grade being larger than or equal to 55% and the ferrum recovery rate being larger than or equal to 90%. The invention provides the downdraught roasting and dry sorting method which has the advantages of simple process flow, low equipment investment, good sorting effect and high ferrum recovery rate. The northwest district of China in which the water resource is insufficient, and the wind resource is abundant has the problem that the siderite resource with high energy storage rate cannot be effectively utilized; by the method provided by the invention, the problem can be solved.