From Ore to Gold: The Innovation and Practice of Gold Mine Concentrator Technology

Detailed Explanation of the Core Process Flow in the Concentrator

(I) Crushing Process: Graded Screening

The crushing stage constitutes the initial critical process for ore entering subsequent processing. The specific flow commences from the raw material storage area: initial feed undergoes primary crushing via a jaw crusher, subsequently being conveyed to a cone crusher for medium crushing. Crushed material undergoes screening via a 2160 double-deck circular screen. Particles exceeding 10 millimetres in size are returned to the cone crusher for further reduction, while material below 10 millimetres is directly transferred to the concentrate storage facility for subsequent grinding operations.

 (II) Grinding Process: Closed-Circuit Circulation

The grinding system processes material from the concentrate bin. Material first enters a grate ball mill for primary grinding, producing a fine-grained pulp. This pulp then passes through a single-screw separator, where larger particles form gravel during sedimentation, while finer particles discharge from the overflow end. The effluent fine-grained pulp undergoes secondary classification via hydrocyclones for more precise particle size separation. Finer particles discharge from the mixing zone directly into the flotation process, while coarser residues are returned to the ball mill for further grinding. This establishes a closed-loop system: ‘ball mill – spiral classifier – hydrocyclone – ball mill’.

 (III) Gravity Separation Process: Precision Screening and Metal Recovery

Gravity separation serves as a crucial recovery method for coarse-grained gold within the ore. The processing plant employs a combined technique of ‘centrifugal pre-screening followed by shaking table concentration’. After coarse selection via a jig at the ball mill discharge, the ore first undergoes preliminary screening in a centrifuge to separate a portion of coarse-grained gold minerals. The pre-concentrated product is then sent to the gravity separation workshop for regrinding, ensuring thorough liberation of gold minerals from gangue minerals.

The reground pulp then undergoes concentration on shaking tables, where gravitational forces further separate gold minerals from impurities. The high-grade gold concentrate obtained is bagged and centrally transported to the smelting stage. Addressing the issue of metal loss in the original gravity separation process—where overflow from the shaking table tailings, after thickening in the inclined plate thickener, was directly discharged—the plant optimised the flow. Overflow from the inclined plate thickener is now redirected to sedimentation tanks for settling and recovery. This effectively reduces the loss of valuable metals like gold, enhancing resource utilisation.

(IV) Flotation Process: Efficient Separation and Fault Prediction

The flotation system employs a classic ‘one roughing, two scavenging, two cleaning’ flow. Fine pulp separated by hydrocyclones enters the flotation stage directly. During flotation, specific reagents (e.g., collectors, frothers) are added to selectively attach gold minerals to bubble surfaces. These rise as froth products (rough concentrates), while gangue minerals remain in the pulp as tailings.

The rough concentrate undergoes two scavenging stages to further recover gold minerals, followed by two cleaning stages to remove impurities, ultimately yielding high-grade flotation gold concentrate. To address increased processing volumes leading to higher flotation concentrations and the risk of individual flotation machines tripping without timely detection, the plant installed an automatic alarm system for the flotation system — — by connecting the idle closed contacts of the flotation machine contactors in series to an alarm. Should any flotation machine trip, the system automatically triggers a visual and audible alarm, alerting personnel to address the issue promptly. This effectively prevents slurry ponding caused by undetected trips, reduces labour intensity, and ensures continuous, stable operation of the flotation process.

(V) Activated Carbon Adsorption and Tailings Disposal Process

Following flotation treatment, mineral slurry requiring further gold extraction proceeds to activated carbon adsorption tanks. Within these tanks, gold-cyanide complexes (where cyanide leaching was employed in prior stages) are adsorbed by activated carbon, forming gold-bearing media prepared for subsequent desorption and electrolytic recovery.

The implementation of dry tailings disposal technology significantly reduces tailings moisture content, enabling direct storage in abandoned mine pits or barren slopes. This approach not only extends the operational lifespan of existing tailings storage facilities but also mitigates systemic risks associated with wet tailings storage, such as dam breaches or overflows, thereby aligning with green mining development requirements.