Preparation method of cold-consolidated pellets suitable for kiln-process phosphoric acid rotary kiln process

Abstract

The invention discloses a preparation method of cold-consolidated pellets suitable for a kiln-process phosphoric acid rotary kiln process. The preparation method comprises the following steps: material grinding, material preparation, mixing, pelletizing, internal pellet packaging and drying. According to the preparation method, an inorganic substance bentonite is matched with an organic matte sodium carboxymethyl starch, and the advantages of bentonite and odium carboxymethyl starch to the quality of the pellets are exerted, so that the reliability and the stability of the quality of the pellets are guaranteed; when the pellets are dried, internal moisture can be dispersed to the surfaces of the pellets through capillary tubes to be evaporated, so that the bursting of the pellets in the drying process is prevented, relatively good hard shells can be formed on the surfaces of the pellets, and the strength of the pellets is guaranteed; by virtue of cooperation of organic and inorganic auxiliary materials, the quality requirements of raw pellets and the dried pellets are guaranteed; by virtue of an intensive mixing machine, the raw materials and the auxiliary materials for pelletizing are uniformly mixed, so that the uniformity and the reliability of the mixing of the materials are guaranteed, and the requirements of a solid phase reaction of the kiln-process phosphoric acid rotary kiln process are met.

Description

technical field [0001] The invention relates to a preparation method of cold-consolidated pellets suitable for kiln phosphoric acid rotary kiln technology. Background technique [0002] The kiln method phosphoric acid process is to grind phosphate rock, silica and reducing agent coal into powder and make pellets. After entering the rotary kiln, the reduction reaction is carried out under high temperature conditions. The reaction is carried out between the solid phase materials inside the pellets. Therefore, in addition to the factors of material fineness, reaction temperature and time, it is very important to increase the reduction rate of phosphorus to make all materials evenly distributed and intimately contacted in the pellet; Dropping, extrusion, friction and other external forces require pellets to have high strength, good wear resistance, and maintain quality stability; The preparation adopts the cold consolidation process. The process is as follows: the finely ground...

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Problems solved by technology

[0002] The kiln method phosphoric acid process is to grind phosphate rock, silica and reducing agent coal into powder and make pellets. After entering the rotary kiln, the reduction reaction is carried out under high temperature conditions. The reaction is carried out between the solid phase materials inside the pellets. Therefore, in addition to the factors of material fineness, reaction temperature and time, it is very important to increase the reduction rate of phosphorus to make all materials evenly distributed and intimately contacted in the pellet; Dropping, extrusion, friction and other external forces require pellets to have high strength, good wear resistance, and maintain quality stability; The preparation adopts the cold consolidation process. The process is as follows: the finely ground phosphate rock powder, silica powder and coke powder are weighed and mixed by the belt conveyor into the double-shaft mixer, and the mixed materials are sent to the disc pelletizer , spray an organic binder made from weathered coal, and make it under the condition of continuous rotation of the disc Large and small pellets are sent to the next process; the above method uses a variety of raw materials for pelletizing, and the selected biaxial mixing equipment has a single blade type and no control means, which cannot meet the requirements of the mixing process, and equipment failures are frequent; In the preparation process of the adhesive, due to the difficulty of liquid-solid separation, the existing domestic filtration equipment is difficult to meet the requirements of filtration, resulting in the instability of the active ingredients in the liquid phase binder due to human factors; the balls made by the above-mentioned prior art The quality of the pellets is unstable, the strength is poor, not wear-resistant, and cannot adapt to the process requirements of the rotary kiln, and the drying efficiency of the pellets is low, and the moisture index is difficult to meet the requirements