Method for preparing yellow phosphorus by low or middle grade phosphorus ore

The invention discloses a method for preparing yellow phosphorus by low or middle grade phosphorus ore, aiming at solving the technical problem that the prior art consumes much electric power, has high demand on the grade of raw material and exerts great negative effect on the ecological environment. In the invention, a vertical kiln is used as the production equipment; the content of phosphorus pentoxide in phosphorus ore is lower than 25%, 2-10% of mineralizer is added to the raw material. The method comprises the following steps; the materiel, silica, coke are mixed according to the weightproportion of 5.6:3:1, the mixture is ground to powder of 200 meshes and is homogenized; cementing agent is added to the mixture for preparing the mixture into an axiolitic raw material pellet, the pellet is dried; then the pellet is placed in the vertical kiln to be preheated to 1100 DEG C to 1200 DEG C; the pellet enters a reducing phase, and when the temperature is raised to 1240 DEG C to 1270DEG C, phosphorus steam is