Low-Grade Zinc Carbonate as Feedstock for Oxide Production

In this unit, low-grade zinc carbonate is used as feed in the Waelz kilns. The final product of this process is zinc oxide with a concentration of 45%.

Initial Upgrading of Low-Grade Ore through Dense Media Separation

This unit performs the pre-concentration of low-grade ores prior to flotation.

When the grade of the extracted ore is too low to be fed directly into the flotation circuit, initial upgrading is carried out in the Heavy Media Separation (HMS) unit. In this process, high-grade particles are separated from low-grade material using dense media technology.

The resulting enriched product, with a suitable grade, is then transferred to the flotation unit for further processing.

The set of operations required to produce lead and zinc concentrates from extracted ore is carried out in the mineral processing plants. These operations include crushing, heavy media separation (HMS), grinding and classification, flotation, dewatering, and drying.

Crushing Unit

The facility operates two crushing units with a nominal feed capacity of 5,000 tons per day. The ore extracted from the mines is first transported and unloaded into the crusher feed bunker, from where it is directed via feeders into a jaw crusher. Here, the ore is reduced to particles smaller than 10 centimeters and discharged onto a vibrating screen for size classification.

Fine particles smaller than 15 millimeters pass through the screen and are sent directly to the plant silo, while oversized material larger than 15 millimeters is transferred to cone crushers for further reduction. The crushed material is then returned to the screen. This closed-circuit crushing and screening process continues until all particles reach a size below 15 millimeters.

The final product from the crushing unit is then transferred to downstream units for concentration and final processing.

The crushed ore from the crushing unit is transferred to the plant silo and then conveyed via dedicated belt systems into the flotation unit, which consists of two main sections: lead flotation and zinc flotation.
The feed first undergoes wet grinding in the primary mill. It is then directed to hydrocyclones for classification. Based on centrifugal force, materials are separated into two streams: particles finer than 75 microns and coarser than 75 microns. The finer fraction (overflow) is sent to the conditioners, while the coarser fraction (underflow) is redirected to a secondary ball mill for further grinding. The material then returns to the hydrocyclones. This closed-circuit grinding continues until the particle size is reduced below 75 microns and the material can be transferred to the conditioners.
In the conditioners, the material undergoes chemical conditioning through the addition of reagents such as collectors, depressants, and frothers, according to the predesigned residence time. The conditioned slurry is then fed into the lead flotation cells, which include the rougher, scavenger, and cleaner stages.
The resulting lead concentrate, with an approximate grade of 60% lead, is sent to designated concentrate ponds. The tailings from the lead flotation stage serve as the feed for the zinc flotation circuit, which includes its own set of conditioners and flotation cells. The final zinc concentrate, with an approximate grade of 50% zinc, is likewise transferred to corresponding concentrate ponds.

The nominal input capacity of the company’s flotation plants is 2,000 tons per day. The main products include sulfide concentrates of lead and zinc, as well as lead and zinc carbonates.