SHAO Guoqiang,Z0U Zheng,ZHU Qingshan

(Institute of Process Engineering,State Key Laboratory of Multiphase Complex Systems,Chinese Academy of Sciences，Beijing 100190,China)

Abstract

Objective The supply of manganese ore in China is heavily dependent on imports with its relatively deficient manganese ore resources but large demands. However, a large number of refractory high-iron pyrolusite has not been effectively utilized. Low-temperature reduction can thermodynamically inhibit the generation of faujasite and ferromanganese spinel phases, solving the problem of over-reduction of high iron soft manganese ores from the source. In order to improve the resource utilization efficiency of refractory high-iron pyrolusites, the fluidized magnetic roasting was carried out for the refractory high-iron pyrolusite from Yunnan. We hope that the methods and results of our research can help to the utilization of such resources.

Methods In this paper, Firstly, the raw ore particles with a particle size of 56 ~ 250 μm were dried and dehydrated for 24 h at 105 ℃ . After that, the pretreated particles were put into a fluidized bed reactor for the reduction reaction. Then, the roasted ore was ground and magnetically separated to obtain iron concentrate and manganese concentrate (tailings). The iron grade and manganese grade were analyzed by chemical titration to calculate the iron recovery rate and manganese recovery rate. Finally, the leaching experiment of manganese concentrate was carried out to calculate the manganese leaching rate and iron leaching rate. 

Results and Discussion The results show that this procedure can lower the reaction temperature below the thermodynamic temperature of the over-reduction reaction, and the iron leaching rate of the manganese concentrate is only 1. 94%. After magnetic separation, the iron grade of the concentrate is 57. 24%, with a recovery rate of 76. 55%, while the manganese grade of the tailing is 24. 41% with a recovery rate of 73. 84%.

Conclusion The Yunnan high-iron pyrolusite used in the experiment is a case of refractory high-iron pyrolusite in China. The iron and manganese particles are associated, and the embedded particle size falls within the range of 15 to 40 μm. The manganese-iron ratio of the manganese concentrate after roasting magnetic separation can only reach 1. 07. The results show that the leaching rate of iron increases significantly above 500 ℃ , indicating the occurrence of an over-reduction reaction. Optimal reduction of the sample can be achieved when the roasting time exceeds 10 minutes. Moreover, when the sample's grinding fineness reaches a proportion of 65% with a particle size of <30 μm, the optimal separation effect can be achieved.

Significance Investigating the law of fluidized magnetization roasting-magnetic separation leaching of refractory high-iron pyrolusite can reduce the reaction temperature, shorten the reaction time, and save low-carbon energy. Additionally, inhibiting the occurrence of over-reduction reaction can improve the utilization rate of iron resources and reduce the consumption of leaching acid and iron removal agents. Low energy consumption, low consumption, and high utilization rate can greatly improve the economy of refractory high-iron pyrolusites and solve the dilemma of difficult utilization of this part of resources. Therefore, research in this area is of great significance for the efficient and comprehensive utilization of refractory high-iron pyrolusite resources.

Keywords: high-iron pyrolusite; fluidization; magnetic roasting; manganic concerntrate; iron ore concentrate

Get Citation:SHAO G Q, ZOU Z, ZHU Q S. Magnetic roasting via fluidized bed and leaching procedure of refractory high-iron pyrolusite[J]. China Powder Science and Technology, 2024, 30(1): 36-45.

Received : 2023-08-17,Revised :2023-10-10,Online:2023-12-12。

Funding Project:国家自然科学基金项目 ,编号 :22278404;中国科学院战略性先导科技专项 (A类)项目 ,编号:XDA29040200。

First Author: :邵国强 (1986—) ,男,副研究员 ,硕士 ,硕士生导师 ,研究方向为矿产资源高效利用。 E-mail: gqshao@ipe.ac.cn。

Corresponding Author:朱庆山 (1969—),男,研究员 ,博士 ,国家杰出青年基金获得者 ,博士生导师 ,研究方向为矿产资源高效利用、流态化过程强化。 E-mail: qszhu@home.ipe.ac.cn。

DOI:10.13732/j.issn.1008-5548.2024.01.004

CLC No:TD792;TB4                  Type Code:A

Serial No:1008-5548(2024)01-0036-10