The chromite beneficiation process can adopt gravity separation, magnetic separation, flotation and other processes according to the mineral composition and properties. However, it is difficult to separate all gangue minerals from chromium by a single beneficiation method. Therefore, in the chromite beneficiation process, a combined beneficiation process is often used. This article will introduce three commonly used combined beneficiation processes through three project cases.
(1) Process Introduction
The magnetic separation-gravity separation combined ore dressing process is a process that combines magnetic separation and gravity separation. The core principle is to separate the gangue minerals by utilizing the difference in magnetism and density between chromium and other gangue minerals.
This combined process first removes strongly magnetic minerals by magnetic separation, and then further concentrates the chromite by gravity separation to improve the grade and recovery rate of the chromite. This combined process can comprehensively utilize the advantages of the two beneficiation methods to improve the beneficiation efficiency.
(2) Project Case
A low-grade chromite mine in Yunnan has a chromium oxide content of only 8.51%, a chromite content of 16.81%, and a magnetite content of only 0.65%. The gangue minerals mainly include serpentine, quartz, etc., and the composition is relatively complex. The beneficiation process that can be adopted by this mine is graded desludging and magnetic-gravity combined separation process.
(1) Process Introduction
The magnetic-flotation combined process utilizes the differences in magnetic properties and surface properties between chromite and gangue minerals to improve the grade and recovery rate of chromite through the synergistic effect of magnetic separation and flotation.
This combined process first removes strong magnetic minerals through magnetic separation, and then further refines the chromite by flotation to improve the grade and recovery rate of chromite.
(2) Project Case
The chromium oxide content of a chromite ore is 35.28%, and the ferrous oxide content is 8.55%. It has a relatively simple structure, coarse particles, and a high degree of dissociation. Its main gangue minerals include olivine, serpentine, chlorite, etc.
After comparing the shaking table gravity separation, shaking table-strong magnetic separation, and strong magnetic separation processes, better indicators were obtained in the wet strong magnetic separation process. The final process adopted was a combined mineral processing process of wet strong magnetic separation-roughing-sweeping separation, and the chromium oxide concentrate grade was 47.61% and the recovery rate was 96.26%.
(1) Process Introduction
Chromite Magnetic-Gravity-Floatation Combined Beneficiation Process is a process that comprehensively utilizes three beneficiation technologies, namely magnetic separation, gravity separation and flotation, to improve the grade and recovery rate of chromite.
This combined process can make full use of the differences in magnetism, density and surface properties between chromite and gangue minerals, combine the advantages of various beneficiation methods, improve beneficiation efficiency and economic benefits, and is particularly suitable for processing complex and difficult-to-benefit chromite ores.
Magnetic-Gravity-Floatation Combined Beneficiation Process:
First, remove the strongly magnetic minerals in the ore through magnetic separation, then use gravity separation to further separate the dense chromite, and finally use flotation to finely separate the fine chromite to achieve effective separation of chromite and gangue minerals.
(2) Project Case
A chromite mine in South Africa conducted a combined process study of "magnetic pre-enrichment-gravity re-enrichment-flotation re-selection".
Most of the main metal mineral chromite is distributed in the fine-grained grade. Effective recovery of fine-grained chromite is the key to improving the total recovery rate.
The project finally obtained a flotation concentrate with Cr2O3 40.89% and a recovery rate of 33.61%; the total yield of the two concentrates was 40.88%, the recovery rate was 82.60%, and the average grade of Cr2O3 was 39.65%.
In actual production, only rich ores with extremely high chromium oxide content are suitable for single gravity separation or magnetic separation. Most chromite ores are poor ores with low chromium oxide content. At this time, we should determine the beneficiation plan through mineral composition analysis tests and beneficiation tests, separate the gangue minerals in a targeted manner, and finally obtain high-grade chromite and recovery rate.
