Limonite is a common iron-bearing ore, typically used in iron and steel production. However, at times, limonite may also contain a certain amount of metallic gold. This gold-bearing limonite can become a valuable metal resource, but its flotation processing is relatively complex. This article will detail the flotation processing steps for gold-bearing limonite.
Ore Characteristics: Limonite typically appears brown to black, with high hardness, and commonly associated minerals include magnetite, hematite, etc. The gold in gold-bearing limonite is disseminated within the ore's lattice or coexists with mineral particles.
Distribution of Gold: Gold usually exists in the form of fine particles or with small particle size in limonite, often adhering to other minerals, making direct extraction difficult.
Particle Size of Gold: The gold particle size in limonite is typically fine, requiring the use of fine-grained flotation agents and special flotation processes for effective extraction.
Crushing and Grinding of Ore
Firstly, the original gold-bearing limonite is subjected to preliminary crushing and grinding to achieve particle sizes suitable for subsequent flotation operations. During the grinding process, care should be taken to preserve the crystallinity of gold and avoid gold loss.
Ore Leaching Treatment
The crushed and ground gold-bearing limonite samples are placed in leaching tanks for ore leaching treatment. The purpose of ore leaching treatment is to expose metallic gold on the surface of the ore, preparing it for subsequent flotation operations. Commonly used leaching agents include acid leaching agents, alkaline leaching agents, etc.
Addition of Flotation Reagents
After ore leaching treatment, an appropriate amount of metallic flotation reagents, such as yellow medicine, black medicine, etc., is added to the leaching tank. These flotation reagents can chemically adsorb onto the surface of gold particles, rendering them floatable.
Air Flotation
The slurry is sent to an air flotation machine for air flotation treatment. In the air flotation machine, a large number of bubbles are generated by introducing air or nitrogen into the slurry, causing gold particles to combine with bubbles to form foam, thereby achieving flotation separation of gold. During air flotation, proper flotation time and flotation speed should be controlled to ensure effective extraction of gold.
Flotation Concentration
After air flotation, the concentration of metallic gold is significantly increased, but further flotation concentration is still required. The flotation slurry is sent to a flotation concentration tank, where gold metal is further extracted and concentrated through gravity settling or centrifugal separation.
Tailings Treatment
After flotation processing, the generated tailings contain high concentrations of gangue and a small amount of metallic gold. For tailings treatment, commonly used methods include reselection or re-flotation to recover unrecovered metallic gold from tailings and reduce resource waste.
Through the above flotation processing steps, effective extraction and separation of gold from gold-bearing limonite samples can be achieved, thereby realizing the recovery and utilization of gold in limonite. In practical applications, flotation process parameters can be adjusted and optimized according to the characteristics of the ore and flotation conditions to obtain better flotation results and gold recovery rates.
