Quartz Vein Gold Deposit Flotation Process and Key Parameters

Quartz vein gold deposits, as a highly representative type of gold deposit, necessitate flotation as the core process for gold extraction due to their mineral composition and intercalation characteristics. Achieving efficient gold recovery and improving concentrate grade hinges on constructing a scientific and stable crushing, grinding, slurry conditioning, and flotation process. The following provides a detailed analysis of the entire standard flotation process and core parameters for quartz vein gold deposits, offering technical reference for similar mineral processing production.

I. Three-Stage Closed-Circuit Crushing: Ensuring Uniform and Controllable Particle Size Entering the Mill

The raw ore is first pre-screened using a heavy-duty screen, then enters a jaw crusher for primary crushing, breaking the material to a suitable particle size. The primary crushed material is conveyed by belt to a cone crusher for secondary crushing, further refining the particle size. The secondary crushed material then enters a circular vibrating screen for further screening. Material with unqualified particle size is returned to the fine cone crusher for regrinding, while qualified material is conveyed to the fine ore bin. The finely crushed material is also returned to the same circular vibrating screen for re-screening, forming a closed-loop cycle to ensure that the particle size of the material entering the mill meets the standards. 

II. Grinding and Classification: Achieving Mineral Liberation

Fine ore is fed into the ball mill at a constant rate, with appropriate grinding concentration and time controlled. The ball mill discharge is classified by a hydrocyclone, controlling the fineness of the overflow material and periodically monitoring it. Return sand is sent back to the ball mill for regrinding, while the overflow material flows into a slurry conditioning tank, preparing for subsequent slurry conditioning and flotation.

III. Slurry Conditioning: Creating a Suitable Flotation Environment

Slurry conditioning is a crucial prerequisite for effective flotation. Reagents must be added in the prescribed order, and stirring time must be controlled: First, add an appropriate amount of lime milk (Ca(OH)₂) to the slurry tank and stir until homogeneous to adjust the slurry pH to a suitable range; then, add appropriate amounts of butyl xanthate and isopentyl xanthate sequentially, stirring until the reagents are fully mixed; finally, add an appropriate amount of pine oil (No. 2 oil) and stir until homogeneous to complete the slurry pretreatment.

IV. Main Flotation Process: Coordinated Efficiency Improvement of Roughing-Cleaning-Scavenging

(I) Roughing Stage

The conditioned slurry is pumped into the roughing flotation tank, maintaining appropriate slurry concentration and air consumption. After flotation for a suitable time, the rough concentrate is skimmed off, and the roughing tailings are sent to the scavenging system for further recovery.

(II) Cleaning Stage

First-stage cleaning: The rough concentrate is pumped into the first-stage cleaning agitator, with appropriate lime added to maintain a suitable pH value and control the appropriate slurry concentration. Flotation is carried out to the specified effect to obtain primary concentrate, and the middlings are returned to the roughing tank for recycling.

Second-stage cleaning: The primary concentrate is sent to the second-stage cleaner, with appropriate slurry concentration controlled, and flotation is carried out to the specified effect to obtain second-stage concentrate. The middlings are returned to the first-stage cleaner.

Third-stage cleaning: The second-stage concentrate is sent to the third-stage cleaner, with appropriate slurry concentration controlled, and flotation is carried out to the specified effect to finally obtain qualified gold concentrate. The middlings are returned to the second-stage cleaner.

(III) Scavenging Stage

Scavenging I: Add an appropriate amount of butyl xanthate to the rougher tailings, stir evenly, and then perform flotation. The froth is returned to the rougher operation.

Scavenging II: Add an appropriate amount of isopentyl xanthate to the tailings from Scavenging I, stir evenly, and then perform flotation. The froth is returned to Scavenging I.

Scavenging III: The tailings from Scavenging II are discharged as final tailings, ensuring that the gold content in the tailings meets the standards.