Is Your Gold Recovery Rate Below 80%? Your Grinding Equipment Might Be the Key.

Wet Pan Mill for Gold Benefication

Wet Pan Mills for Gold Ore Processing: The Core of Efficient Gold Grinding

In the long process of gold ore processing, crushing and grinding the ore is the first and most crucial step. It breaks down the raw ore from large chunks into fine particles, allowing the gold minerals to be fully liberated and laying the foundation for subsequent enrichment and recovery. Among numerous grinding equipment, the wet pan mill (also known as a wet grinding mill or gold ore mill) occupies an irreplaceable position in small and medium-sized gold mines, especially in hard rock and placer gold processing plants, due to its unique structure, superior performance, and excellent economics. As a mining equipment manufacturer with 20 years of experience, we will provide you with an in-depth analysis of this classic gold ore processing tool.

In-depth Analysis of Wet Pan Mills: How Does It Work?

A wet pan mill is a disc-type grinding equipment that combines crushing, grinding, and mixing functions. Its working principle is not simply impact crushing, but rather focuses on continuous grinding and compression.

Its core structure includes a fixed grinding disc (pan) and 2-4 heavy grinding wheels that roll along a fixed track on the disc. During operation, the motor drives the main shaft through a reducer, causing the grinding wheels to roll inside the pan filled with ore and water (or mercury, cyanide solution). The ore is repeatedly crushed and ground under the gravity and compressive and frictional forces generated by the rolling wheels, and fully mixed with the liquid to form a slurry. Finally, the qualified fine-particle slurry is discharged from the overflow port at the edge of the pan and enters the next separation process.

Gold grinding machine structural diagram

Why Choose a Wet Pan Mill? Overview of its Core Advantages

Compared with traditional ball mills, wet pan mills show significant advantages in specific application scenarios, which is why they have been widely used in small gold mines worldwide for centuries:

1. Low Investment and Operating Costs: The equipment has a simple structure, is easy to manufacture and maintain, and the initial investment is far lower than that of ball mills with the same processing capacity. At the same time, its energy consumption is lower, saving investors a significant amount of electricity costs.

2. Suitable for amalgamation or direct cyanidation: The grinding pan can be used as a closed or semi-closed container, making it ideal for adding mercury (amalgamation method) or sodium cyanide while grinding, achieving simultaneous grinding and leaching, simplifying the process, and improving the primary gold recovery rate.

3. Strong adaptability to ore properties: Particularly adept at processing ores containing clay, those with high toughness, or wet ores. Its crushing action effectively handles sticky materials that would clog other grinding mills.

4. Controllable product particle size: By adjusting the grinding wheel pressure, feed rate, and water volume, the discharge particle size can be controlled within a certain range to meet the requirements of different beneficiation processes (such as gravity separation and cyanidation).

5. Small footprint and short construction period: The equipment is compact, and the foundation is simple, making it particularly suitable for mining projects with complex terrain, limited investment budgets, or those requiring rapid commissioning.

What makes our wet grinding mill unique?

Based on 20 years of design and manufacturing experience, we have made several optimizations and upgrades to traditional wet grinding mills:

• Enhanced gear transmission system: Using high-quality alloy steel gears, carburized for 50% improved wear resistance, resulting in smoother transmission, lower noise, and longer service life.

• Replaceable wear-resistant liners: Both the grinding pan and grinding wheels are covered with high-chromium alloy wear-resistant liners.  These liners have high hardness and impact resistance. When worn, only the liners need to be replaced, not the entire base or grinding wheel, significantly reducing long-term maintenance costs.

• Flexible configuration options: Available in various specifications from Φ1200 to Φ1600, supporting both electric motor and diesel engine dual-drive modes to meet the needs of areas with and without electricity. Amalgamation type or standard type can be designed according to customer process requirements.

Gold grinding machine customer site 

Successful Case Study: Helping a Tanzanian Customer Improve Recovery Rate

In 2022, we provided a complete solution to a gold mine customer in Tanzania, the core equipment of which included a Φ1500 wet grinding mill. The mine's ore had medium hardness but contained a certain amount of clay.

• Challenge: The original process using a small jaw crusher + hammer crusher + shaking table resulted in a gold recovery rate of only 65%-70%, with significant loss of fine gold particles. • Our Solution: We adopted a simplified process using a "jaw crusher -> Φ1500 wet grinding mill (grinding and cyanidation simultaneously) -> carbon pulp adsorption tank."

• Results: The wet grinding mill achieved simultaneous fine grinding and cyanide leaching of the ore, significantly increasing the gold leaching rate. Ultimately, the overall gold recovery rate of the system stabilized at over 88%, and the client recovered their entire equipment investment within 8 months.

Related Equipment Recommendations: Building an Efficient Mineral Processing Production Line

Wet grinding mills rarely operate alone; an efficient gold mineral processing production line typically includes:

• Crushing equipment: Jaw crusher (coarse crushing), cone crusher/hammer crusher (fine crushing), to provide suitable feed particle size for the wet grinding mill.

• Classification equipment: Spiral classifier or hydrocyclone, which can form a closed-circuit grinding system with the wet grinding mill to control product fineness.

• Separation equipment: Centrifugal concentrator, shaking table (for gravity separation), or carbon pulp adsorption tank, electrolytic cell (for cyanide gold extraction).

• Auxiliary equipment: Feeders, mixing tanks, water pumps, etc.

Frequently Asked Questions (FAQ)

1. What are the main differences between a wet grinding mill and a ball mill?

The core difference lies in the grinding principle. Wet grinding mills primarily use crushing and grinding, suitable for small and medium-scale operations, especially gold mines requiring simultaneous grinding and leaching; ball mills primarily use impact and grinding, have a larger processing capacity, and produce finer and more uniform particle sizes, suitable for large-scale processing plants. Wet grinding mills are more economical, while ball mills are more efficient and versatile.

2. What is the processing capacity of a wet grinding mill? What is its service life?

The processing capacity depends on the model and ore hardness. For example, our Φ1200 model processes approximately 0.8-1.5 tons per hour, and the Φ1600 model can reach 2-4 tons. Under normal use and maintenance, the core transmission components can last 5-8 years, and the wear-resistant liners can last 6-18 months depending on the abrasiveness of the ore.

3. Can wet grinding mills be used to process other minerals?

Yes. Although it is best known in the gold mining industry, it is also widely used in the grinding of non-ferrous metal ores such as silver, lead, tungsten, and molybdenum, as well as in the regrinding of iron ore. It is suitable for the fine grinding and mixing of various medium-to-low hardness minerals.

Perfect after-sales service

Baichy Heavy Industry provides professional on-site guidance for installation, training of workers, and other services to ensure that customers can use the equipment smoothly.

The company has a complete after-sales service system, which can provide customers with timely technical support and equipment maintenance services to ensure the long-term stable operation of the equipment.

To prevent the rights and interests of customers from being infringed, Baichy Heavy Industry reminds customers: please contact our customer service staff through the official website of Baichy Heavy Industry , or add WhatsApp: 15093222637 ; or send an email to: [email protected] , we will get in touch with you as soon as possible and provide you with the most professional service in the industry.

Baichy Heavy Industry

Baichy Machinery is a factory supplier of mining machinery, mainly focusing on stone crushers, powder grinding mills, and mineral beneficiation plants. We can offer you a free design and completed solutions according to your project.

Baichy Heavy Industry has grown into a high-tech mining equipment comprehensive enterprise, integrating R&D, manufacturing, sales, and after-sales service, Passing ISO9001:2015 quality management system certifications. The main products are mobile jaw crushing plants, construction waste crushing plants, PE jaw crushers, VSI sand-making machines, Symons cone crushers, single-cylinder hydraulic cone crushers, PCX high-fine crushers, grinding mills, ball mills, and full sets of beneficiation equipment with an excellent level.