Method for preparing silicon alloy with waste silicon sludge

The invention relates to a method for preparing silicon alloys by using waste silicon mud, comprising the following steps: a. melting the mixture of silicon carbide and silicon powder after preliminary separation of waste silicon mud at high temperature, pouring the molten silicon metal liquid in the upper layer into the preheated b. Put part of the silicon back into the furnace, raise the temperature of the furnace to 1550°C, add iron powder while stirring, wait for the iron powder to melt, add covering agent, and keep warm for later use; c. Pour the remaining silicon into the furnace , the furnace temperature rises to 850°C, add aluminum powder, add covering agent, and keep warm for later use; d. Add manganese elemental metal, ferrosilicon alloy, and copper elemental metal in batches, heat up, and turn on the ultrasonic device for reaction at the same time; e. Put the molten metal in Into the mold extrusion molding. The silicon alloy prepared by the method has the characteristics of low density, high thermal conductivity, good electrical conductivity, high hardness, excellent thermomechanical stability, high compactness, etc., the whole production process realizes zero emission, and solves the outstanding environmental protection problems in this field.