Balling method using medium- and low-grade phosphate rocks or ground phosphate rocks

Abstract

The invention relates to a balling method using medium- and low-grade phosphate rocks or ground phosphate rocks. The method comprises the following steps: S1, preparing materials, namely A, 85-100 parts of 60-120-mesh medium-grade and low-grade phosphate rocks or ground phosphate rocks, B, 1-10 parts of water or aqueous liquor of phosphoric acid, C, 2-8 parts of coke powder with the granularity of 60-120 meshes and D, 1-8 parts of one or more of phosphate fire clay, kaolin, sodium silicate, sodium carbonate, calcium carbonate and serpentine; S2, stirring, namely after uniformly mixing the raw materials, pressing the mixture into balls by use of a dry powder ball press machine, after pre-drying, delivering the mixture to a vertical calcining kiln, using purified yellow phosphorus tail gas, heating to 850-950 DEG C; starting roasting to obtain a finished product. The method is free from binders and low in cost, and the medium-grade and low-grade phosphate rocks are not hardened. The value of the medium-grade and low-grade phosphate rocks can be improved, and the ground phosphate rock of a mine can be fully utilized. The phosphate rock balls prepared are suitable for production of yellow phosphorus or calcium magnesium phosphate fertilizers.

Description

technical field [0001] The invention relates to a pelletizing method utilizing medium and low-grade phosphate rock or phosphate rock powder. Background technique [0002] Phosphate rock is a non-renewable resource. It is mainly used as the main raw material for the production of yellow phosphorus and phosphate fertilizer. Mineral resources in China are mainly distributed in Yunnan, Guizhou, Sichuan and other places. However, judging from the current development situation, high-grade phosphate rock resources suitable for the production of yellow phosphorus and calcium-magnesium phosphate fertilizers are constantly decreasing, and the development and utilization of low- and medium-grade phosphate rock resources is more urgent. High-grade phosphate rock will produce a lot of "powder ore" in the process of mining and use, while the production of yellow phosphorus and calcium magnesium phosphate fertilizer mainly uses "lump ore" of phosphate rock to produce. In terms of utiliz...

AI Technical Summary

Problems solved by technology

Its main disadvantages are: the cost of the binder is high; the binder is not temperature-resistant, and it is pulverized during the production of yellow phosphorus, which has no effect; due to the addition of the binder, the grade of the phosphate rock is diluted; The amount of knot is small, the mixing material is difficult to be uniform, the quality of the pellets is unstable, and the pelleting rate is not high, and it is not suitable for pelletizing phosphate rock powder with high loss on ignition and for yellow phosphorus production.

For example, Chinese patent CN101531351A discloses a method for preparing yellow phosphorus from low-grade phosphate rock, in which a binder is added. While the cost increases, compaction is also prone to occur during the sintering process of the vertical kiln, making it difficult to exit the kiln.