Selective grinding of bauxite - agglomeration flotation desiliconization

A, bauxite selective grinding an agglomerate flotation desilication

So far, there are two kinds of bauxite ore dressing methods for industrial applications. One is the accumulation of enriched bauxite ore, and the other is the desiliconization of sedimentary bauxite. In 2003, the “selective grinding-agglomeration flotation desiliconization” technology of bauxite developed by Central South University was successfully applied in the alumina production line of Zhongzhou Aluminum Company's beneficiation-Bayer process.

Due to the high content of Al ₂ O ₃ in the bauxite ore, the yield of the foam product being floated is inevitably higher, often reaching 80% or even higher. Therefore, according to the conventional method, the first flotation of the bauxite-type bauxite is caused by two problems: (1) the concentration of the slurry in the flotation tank is drastically reduced, and the two grades are difficult to collect, and the coarse particles are easy to sink; 2 Fine-grained silicon minerals are easily incorporated into foam products, affecting the quality of concentrates.

The selective grinding-cluster flotation desiliconization process of bauxite firstly utilizes the selective disintegration characteristics of bauxite for selective grinding, so that the coarse-grained aluminum-silicon ratio in the grinding product is improved, and the coarse-grained The grade is directly used as a concentrate, and the fine fraction is treated by selective flotation flotation to enhance the separation of aluminum and silicon and the recovery of fine-grained aluminum minerals. The flotation process is divided into two major cycles: rough, sweeping and selection. The coarse concentrate obtained from the coarse and sweeping cycles enters the selective cycle to produce flotation concentrates; the selected cycle tailings and coarse sweeping tailings are combined as the final tailings. The principle flow of the selective grinding-agglomeration flotation desiliconization process is shown in Figure 1.

Fig.1 Principle of selective grinding-bundling flotation desiliconization of bauxite

The process fundamentally solves the problems of coarse particle recovery, coarse interference of low concentration silicon mine mud, and can greatly reduce the amount of flotation reagent, improve the processing capacity of the flotation section and the selectivity of aluminum and silicon separation. Improve the selection indicators and economic benefits, and reduce the organic content of the concentrate.

Table 1 shows the test results of selective grinding-agglomeration flotation desiliconization of Henan and Shanxi bauxite. It can be seen that the selective grinding-aggregation flotation desiliconization process has good adaptability to bauxite of different origins and different aluminum-silicon ratios, and can obtain excellent sorting indexes. Moreover, compared with the industrial test process of the “Ninth Five-Year Plan” in 1999, the treatment capacity of the same ore (Zhongzhou Mine) increased by 24.47%, and the amount of sodium carbonate, dispersant and collector was 66.62% of the original process, respectively. % and 53.83%.

Table 1 Results of selective grinding and agglomeration flotation desiliconization of bauxite

Bauxite selective grinding-agglomeration flotation desiliconization technology as a beneficiation desiliconization process in the mineral processing-Bayer process alumina production process of Zhongzhou Aluminum Co., Ltd., since it was put into production in October 2003, it has achieved good technical and economic indicators. . The bainite ore dressing index of the first year of the 300 kt/a production line of Zhongzhou Aluminum Company was completed: the ratio of aluminum to silicon in the ore was 5.0-5.7, the ratio of aluminum to silicon in concentrate was 10.3 to 11.7, and the recovery rate of concentrate in Al ₂ O _{3 was} 84.5%. 89.0%; its ore dressing cost is equivalent to 20% of the original mine purchase price. The purchase price of low-grade bauxite is much lower than that of Bayer process, so it is economically suitable to use beneficiation concentrate as raw material for Bayer process. Since October 2004, the production cost of the mineral processing-Bayer process of the Zhongzhou Aluminum Company (the ore-to-silicon ratio of 5.6 or so) has been equivalent to the cost of the strengthening sintering method (the ore-aluminum-silicon ratio is about 6.8), which is basically the same as the traditional Bayer method. In view of the cost-advanced and competitive nature of the enhanced sintering process for the production of alumina, this is a strong demonstration of the cost potential and development potential of the beneficiation-Bayer process.

2. Problems in the practice of desiliconization in bauxite ore dressing and future work directions

From the perspective of industrialization of bauxite ore desiliconization technology, it is believed that the main problems in the practice of desiliconization of bauxite ore and the future work direction are as follows:

(1) Research and development of treatment technology and scheme for bauxite ore dressing desiliconization tailings. In the current industrial practice, the problems of solid-liquid separation, tailings storage and further utilization of bauxite ore dressing tailings have not been solved well. Bauxite ore dressing desiliconization tailings with fine particle size and low concentration are inevitable problems in any beneficiation desiliconization method. This is determined by the ore properties of bauxite. Changing the beneficiation method can only change the sedimentation performance of tailings. . Therefore, how to solve the problem of bauxite tailings treatment fundamentally is the work that needs to be carried out in the future. It is necessary not only to improve the settlement performance, compression performance and filtration performance of bauxite tailings, but also to break through the conventional ideas and study the new scheme of tailings treatment.

(2) In-depth study of the relationship between the properties of bauxite ore and de-siliconization of ore dressing. In-depth study of the relationship between the properties of bauxite ore and de-siliconization of beneficiation can help to accurately evaluate the selectivity of bauxite in each mining area and fully utilize the bauxite resources in China, and improve the desiliconization method for bauxite ore dressing. Work efficiency and beneficiation effects are also very beneficial.

(3) Explore the possibility of further increasing the ratio of aluminum to silicon in concentrates. This will not only provide concentrate for the alumina industry, but also promote the advancement of bauxite ore dressing technology . The selective disintegration of bauxite, the combined sorting of multiple force fields, and the research and development of high-efficiency flotation reagents are the future research directions.

Third, the conclusion

(1) China's bauxite resource reserves are very different from China's alumina production capacity, and the degree of bauxite resources is becoming more and more worrying. Bauxite ore dressing is of great significance to the full and reasonable utilization of medium and low aluminum and silicon resources of more than 80% of China's bauxite reserves. The main purpose of bauxite ore dressing in China is to desiliconize the ore and obtain high-aluminum-silicon concentrate.

(2) The relationship between the properties of bauxite ore and de-siliconization of beneficiation is: the accumulation type diaspore-type bauxite is washed and enriched, and the sedimentary diaspore-type bauxite is the main demineralization of ore dressing. Object; the selective disintegration characteristics of diaspore-type bauxite is an important basis for desiliconization of bauxite ore and a criterion for the selectivity of ore. The presence of diaspore in the form of aggregates is The basis of selective disintegration; the essence of bauxite ore desiliconization is the removal of fine-grained silicon-containing minerals.

(3) Bauxite selective grinding-agglomeration flotation desiliconization process utilizes the selective disintegration characteristics of bauxite ore, strengthens the separation of aluminum and silicon by selective grinding and selective agglomeration flotation, coarse and fine grade Aluminum minerals are combined, and the amount of flotation reagents is greatly reduced, the processing capacity is improved, and the technical and economic indicators are good. It has been successfully applied in the mineral processing-Bayer alumina production process of Zhongzhou Aluminum Company.

(IV) Problems in the practice of desiliconization of bauxite ore dressing and future work direction: research and development of treatment technology and scheme for desiliconized tailings of bauxite mine; in-depth study of the relationship between the properties of bauxite ore and desiliconization of ore dressing; The feasibility of the ratio of mineral aluminum to silicon.