Method for refining low-carbon ferromanganese alloy through poor-manganese slag

The invention relates to a method for refining low-carbon ferromanganese alloy through poor-manganese slag. The method includes the steps that 1, silicomanganese slag washing iron, manganese ore and the poor-manganese slag are combined and added into a refining furnace as furnace charge, the manganese ore in the furnace charge is gradually decomposed and reduced under the high temperature condition, a primary smelted product is obtained, and after the primary smelted product is separated, liquid mid-carbon ferromanganese and new manganese slag are obtained; and 2, the new manganese slag and preheated ferrosilicon powder are combined and put into a shaking ladle for the first time of shaking smelting desilication, after final slag on the upper layer is removed, a proper amount of preheated manganese and lime are put into low-silicon manganese-silicon alloy liquid on the lower layer of the shaking ladle, the second time of shaking smelting desilication is carried out, the poor-manganese slag on the upper layer