Filter Media Requirements in the Mineral and Mining Industry

Filtration technology is crucial in the mining industry, playing a key role in the processing of ores and minerals. Concentrates and tailings, need effective dewatering to reduce moisture content and manage waste. Efficient filtration improves the quality of concentrates, lowers transportation costs, and minimizes environmental impact.

Advanced filtration equipment such as filter presses or vacuum filters in combination with textile filter cloths that are well matched to the process are essential for handling the high demands of mining operations. These systems enhance operational efficiency, reduce energy consumption, and support sustainable practices.

As specialists in textile filtration manufacturing, we thrive to serve our customers with customized products that are ideally suited to their operation’s respective application.

Particularly in mining applications, there are sharp particles in the suspension that can damage the filter cloth. Friction occurs during each cycle through the cake discharge and filling processes, which results in chafing of the cloth. These conditions in the mining industry require a filter cloth with characteristics suited for the demands:

→ Resistance to mechanical abrasion and dimensional stability (i.e. drape over cloths)
→ Easy installation of filter cloths
→ Good cake release
→ Non-blinding structure & high capacity  
→ Clear filtrate 
→ Long service life (≥8,000 cycles)

Cloth Abrasion Resistance Testing Results

The extraction of gold in mining poses a special challenge to filtration due to the addition of chemicals. This process is widely known as Merrill-Crowe process and a used method for the recovery of gold and silver from cyanide solutions. The process involves removing precious metals from cyanide leach solutions through a series of steps, including filtration.

Leaching Process:

The ore containing gold and silver is ground and mixed with a cyanide solution, which dissolves the precious metals. This creates a “pregnant” solution containing dissolved gold and silver.

The pregnant solution often contains fine suspended solids such as clay, silt, and other particulates. These solids must be removed, as they can interfere with the process and reduce efficiency.

Clarifiers like pressure leaf filters are used for this purpose. The pregnant solution is passed through clarifiers—typically large tanks where flocculants (chemicals that promote the clumping of fine particles) are added. This helps to settle out the suspended solids.

Clarifiers work through sedimentation, allowing the clear solution to overflow while the solids settle to the bottom. The clarified solution is then passed through filters (such as leaf filters) to remove any remaining fine particles, resulting in a clean, clarified solution.

Filtration requirements & solutions for clarification

Tailings are the leftover materials after extracting valuable minerals. They primarily consist of fine slurry, rock dust, chemicals, and residual minerals. Tailings are a byproduct that must be properly managed to minimize environmental and safety risks.

Key Aspects of Tailings Management:

→ Tailings Ponds: A common method for storing tailings is the creation of large, enclosed ponds. These ponds allow solids to settle and water to clarify, which can be reused or treated and released back into the environment.

→ Dry Stacking: In water-scarce regions, tailings can be dry-stacked, where water is removed from the tailings, and the solids are compacted into “dry stacks.” This method reduces the risk of dam failures and environmental disasters.

→ Environmental Monitoring and Rehabilitation: Continuous monitoring of tailings storage facilities to ensure stability and safety. After mining operations cease, tailings facilities are rehabilitated to prepare the land for safe reuse or natural restoration.

Filter cloths in mining applications are exposed to extremely high mechanical load, causing abrasion mainly in feeding areas. Increasing the lifetime of filter cloths is important for reducing OPEX costs. Our filter cloths improve your production by offering a longer lifetime, perfect dewatering and cake separation. We also use a special rubber material to minimize abrasion in feeding areas, extending lifetime of our filter cloths significantly.

In addition to the selecting the perfect fabric, a perfect design and strategic reinforcements are decisive for the durability of the filter cloth. The feeding shoes made of rubber and metal tend to rub through the cloth material.

Most frequent damages occur in the area of the feeding shoes.

Under a sand blasting test, our production material OMS 557 has far exceeded expectations and demonstrated outstanding tenacity under the most extreme conditions.

Case Study:

→ Customer: silver mine with 2x FFP 3512 with 100 Plates and cloths size: 2.420×3.982mm
→ Application: Silver Tailings, with a high content on flocculants, PSD 30-40µm and cycle time 15-16 min.
→ Issues: sticky cake, clogging
→ Cloths in use: Multifilament with 20cfm

Our Solution: NKD 11299 Nylon Monofilament with 60cfm

Conclusion: Provides lifespan of 8,290 cycles against the previous 4,000 cycles. It also provides benefit for the filter press as less shaking of the cake is required.

General:

→ Vacuum belt filters are continuously operation filters.
→ Application: Phosphoric acid for fertilizer industry and filtration of copper concentrates.

Horizontal vacuum belt filters

Our Solution: DID 11137
→ Improved service lifetime up to 40%
→ Increased filtration throughput up to 25%
→ Better residual moisture possible
→ Higher separation efficiency and less solids in the filtrate
→ Test against two competitors on the same plant
→ Belt width up to 4.5m

Horizontal pan filters

Our Solution: PPD 3115 and PPD 90314
→ PPD 3115: our standard solution for hemi-hydrate
→ PPD 90314: premium grade solution for hemi-hydrate
→ Longer service life due to:
→ Greater thickness (+0.2mm)
→ Higher tensile strength (+1100 N/5cm)
→ Thicker yarns (+0.1mm in warp and weft)
→ Heat resistant PP yarns

Horizontal pan filters

Our Solution: PPPD 3146
→ Double layer fabric
→ No need of drainage fabric/backing cloth
→ Better residual moisture
→ Higher throughput
→ Belt width up to 8m x 25m

Disc Filters

Success Story: Ferrutex® elastic filter bags
→ Elastic stretch Nylon bags (multifilament)
→ “Self cleaning” bag
→ High capacity all the time
→ Durable = long service life
→ Clear filtrate
→ Dry cake

Disc filter steel sectors

Newly designed steel sector with the following benefits:
→ Very light segment weight of only 18 kg instead 28kg
→ Fast and easy segment change due to the special bayonet shape of the segment foot (just one operator)
→ Optimized hydraulics ensure fast filtrate drainage and efficient compressed air blow-back for cake discharge
→ No need for a backing cloth
→ Shape of segments helps to seal the filter bag and prevents product loss
→ Special groove and no need to use screws anymore

We could run laboratory analysis of the filter cloth with subsequent analysis of the results. This includes determination of: