Method for producing industrial phosphoric acid by tunnel kiln

Abstract

The invention discloses a method for producing technical grade of phosphoric acid in tunnel kilns. The method comprises the steps of pulverizing phosphorite, silica and anthracite; mixing phosphorite powder, silica powder and anthracite cuff uniformly in proportion; adding a cementing agent to prepare material lumps; coating the material lumps with a wrapping agent and baking; conducting tunnel kiln reduction: introducing the material lumps into a tunnel kiln, heating, and pushing waste materials from the kiln after the phosphor element is basically released from the material lumps; hydrating: introducing a gas from the tunnel kiln into a hydrated tower to conduct hydration absorption so as to obtain crude acid, and preparing the technical grade of phosphoric acid after the crude acid is purified. By using the method, the technical grade of phosphoric acid is produced by adopting the tunnel kiln, and the reduction reaction is conducted mainly in the tunnel kiln, thereby improving the reduction efficiency, saving fuels, reducing production cost, reducing corrosion to devices and mechanical consumption, being in accordance with the main trend of energy conservation, environmental friendliness, and recycling utilization, and having wide promotion and application space.

Description

technical field [0001] The invention relates to the preparation of industrial-grade phosphoric acid, in particular to a method for producing industrial-grade phosphoric acid in a tunnel kiln. Background technique [0002] The industrial production methods of phosphoric acid mainly include wet method, thermal method and newly emerging kiln method. The wet method mainly uses sulfuric acid to decompose phosphate rock to produce phosphoric acid. This method requires a large amount of high-quality phosphate rock and sulfuric acid, and also produces a large amount of phosphogypsum waste residue. The thermal method is mainly to produce yellow phosphorus by electric furnace method, and then burn it to absorb phosphorus pentoxide to produce phosphoric acid. This method requires medium and high-grade phosphate rock and a large amount of electric energy. At present, the kiln method to produce phosphoric acid is mainly divided into two categories: rotary kiln and tunnel kiln, but they ...

AI Technical Summary

Problems solved by technology

[0003] Tunnel kiln is named for the tunnel similar to a cave, and is widely used in ceramics, refractory materials, building materials, powder metallurgy and other industries. Its main advantages are low fuel consumption, high thermal efficiency, high degree of automation, and good working conditions; the main disadvantage is infrastructure. The investment is large, the thermal system is not easy to adjust frequently, the amount of steel is large, and there are many ancillary equipment, so it is mostly used for products with large output and a single variety