How to Select the Right Beneficiation Process for Your Antimony Ore Type?

Selecting the correct antimony ore beneficiation process is a critical decision that depends entirely on the ore’s mineralogy. Antimony is a specialized metal, and its processing requires a different approach than more common commodities like iron or copper. The physical and chemical properties of the antimony ore types dictate the entire flowsheet, the choice of antimony processing equipment, and the financial viability of the project. A process that works perfectly for one type of ore will fail completely on another. This guide explains how to make the right choice for your specific deposit.

How Are Industrial Antimony Ore Types Classified?

The first step in any antimony ore processing project is to identify the mineral composition. This classification determines the entire technical route. Antimony ores are divided into three main industrial types based on their mineral content.

1. Single Antimony Sulfide Ore: In this type, the only antimony mineral of economic value is stibnite (Sb₂S₃). This is the primary and most important source of antimony worldwide. The processing goal is straightforward: concentrate the stibnite.
2. Sulfide-Oxide Mixed Antimony Ore: This ore contains both stibnite and secondary antimony oxide minerals (like stibiconite or cervantite). These ores form in the transition zone where sulfide deposits have been partially weathered. They are more complex because standard flotation only recovers the sulfide portion.
3. Refractory Antimony Oxide Ore: This ore consists almost entirely of antimony oxide minerals. These ores do not respond to flotation, making them “refractory” to conventional sulfide processing methods and requiring a completely different approach.

What is the Process Flow for Single Antimony Sulfide Ore?

For a single antimony sulfide ore, where stibnite is the target mineral, the processing method depends on how the stibnite is distributed in the rock. Stibnite is very soft and brittle, which makes it prone to creating ultra-fine particles (“slimes”) during grinding. Slimes are difficult to recover. Therefore, the best process for stibnite beneficiation minimizes over-grinding.

A highly effective and common method is the gravity-flotation combined process. This approach uses the strengths of both techniques.

1. Gravity Separation First: After coarse crushing, the ore is screened. The coarser particles are sent to a gravity separation circuit, often using a Jigging Separator Machine. Because stibnite is much denser than the waste rock, the jig can recover a significant amount of coarse, liberated stibnite early. This is a low-cost, high-efficiency step.
2. Flotation for Fines: The finer material, along with the tailings from the jig, is then sent to a grinding circuit with a Ball Mill. After grinding, the slurry is treated in a Flotation Machine circuit. Flotation is more effective at recovering the fine stibnite particles that cannot be captured by gravity. This combined flowsheet maximizes the overall antimony recovery rate.

How Do You Treat Mixed and Refractory Antimony Ores?

Processing sulfide-oxide mixed antimony ore is more challenging because flotation will not recover the oxide minerals. The most common solution is a variation of the combined process:

1. Gravity Concentration: Use gravity methods like a Shaking Table to recover both coarse stibnite and some of the denser oxide minerals together into a mixed concentrate.
2. Sulfide Flotation: The tailings from the gravity circuit are then sent to flotation to recover the remaining fine stibnite.
3. Oxide Recovery: The tailings from flotation, which now contain the unrecovered oxide minerals, might be treated by other methods or, if the grade is too low, discarded. For some high-grade mixed ores, a direct pyrometallurgical enrichment (smelting) process is used.

For refractory antimony oxide ore, froth flotation is not an option. The main method is gravity separation if the minerals are coarse enough. If the ore grade is sufficiently high, it is often mined and sold directly to a specialized smelter without any on-site concentration.

How Do You Achieve Recovery of Associated Metals?

Antimony ores frequently contain other valuable metals like gold, tungsten, or mercury. A successful antimony ore beneficiation process for these complex ores must include steps for the comprehensive recovery of multiple metals.

For a gold-bearing antimony ore, the process is carefully designed for antimony-gold separation technology. Often, a gravity-flotation process is used first to create a mixed antimony-gold concentrate. This mixed concentrate is then treated further. A common method is to use leaching to dissolve the gold, leaving the antimony minerals behind as a solid for separate processing. In other cases, selective flotation can produce a separate gold concentrate and an antimony concentrate. The exact method depends on the specific minerals and their associations, which must be determined by testing.

What is the Decisive Role of Mineral Processing Tests?

A mineral processing test procedure is not optional; it is the most critical step in designing a profitable antimony production line. An ore that looks simple can have complex mineral intergrowths or problematic impurities that are only revealed through detailed lab work. You cannot select an antimony process selection from a textbook.

The testing process provides essential data:

• Mineral Composition: Identifies all valuable and waste minerals.
• Liberation Size: Determines the optimal grind size to free the stibnite without creating excessive slimes.
• Process Suitability: Confirms which methods (gravity, flotation, etc.) will work and predicts the potential recovery rates.
• Reagent Scheme: Defines the best and most cost-effective chemical recipe for flotation.

Investing in a proper test report from a qualified lab is the best way to minimize risk and ensure your plant is designed correctly from the start.

What Key Equipment is in a Complete Antimony Production Line?

Stage	Key Equipment	Purpose	Your Benefit
Crushing	Jaw Crusher, Cone Crusher	Reduce large run-of-mine ore into smaller, manageable sizes for grinding.	Prepares material for efficient liberation.
Grinding	Ball Mill, Spiral Classifier	Grind the ore to the target liberation size in a water-based slurry.	Frees valuable minerals from waste rock.
Gravity Separation	Jig Separator, Shaking Table	Recover coarse, heavy stibnite particles using density differences.	Low-cost, early recovery of high-grade antimony.
Flotation	Flotation Machine, Agitator Tanks	Selectively float fine stibnite particles away from waste rock.	Recovers fine antimony that gravity would lose.
Dewatering	Thickener, Filter Press	Remove water from the final antimony concentrate to prepare for shipping.	Produces a saleable product with low moisture.

Common Questions about Antimony Processing

Question 1: What is the biggest challenge in stibnite beneficiation?

The biggest challenge in stibnite beneficiation is managing its brittle nature. Stibnite easily over-grinds into ultra-fine particles, or ‘slimes.’ These slimes are difficult to recover with both gravity and flotation methods, leading to significant antimony losses.

Question 2: Why is a gravity-flotation combined process common for antimony?

A gravity-flotation combined process is common because it leverages the strengths of both methods. Gravity separation efficiently recovers coarse stibnite at a low cost. The finer particles are then treated by flotation, which is more effective for fine material. This dual approach maximizes the overall antimony recovery rate.

Question 3: How do you separate arsenic from antimony concentrate?

Separating arsenic from antimony concentrate is a key challenge in flotation. It is achieved chemically by using specific ‘depressant’ reagents and carefully controlling the pH of the slurry. This prevents the arsenic minerals from floating while allowing the stibnite to be recovered.

Question 4: Can you process antimony oxide ore with flotation?

No, standard froth flotation is ineffective for antimony oxide ores. The chemical collectors used in flotation are designed for sulfide minerals. Oxide minerals have a different surface chemistry and require different methods, such as gravity separation or direct pyrometallurgical enrichment.

Summary and Recommendations

Choosing the right antimony ore beneficiation process is a matter of precise technical evaluation, not guesswork. The correct path is always determined by the ore itself.

1. Identify Your Ore Type: The first step is to classify your ore as sulfide, mixed, or oxide.
2. Use Combined Methods for Stibnite: For most sulfide ores, a gravity-flotation combined process offers the best balance of cost and recovery, minimizing the slime problem.
3. Address Complexity Early: For mixed ores or those with valuable by-products like gold, your flowsheet must include specific circuits for their separation and recovery.
4. Prioritize Testing: Never design a plant without a comprehensive mineral processing test. It is the single most important investment to ensure a profitable operation.

About ZONEDING

Since 2004, ZONEDING has been a manufacturer of beneficiation equipment. We have extensive experience in designing and supplying complete solutions for complex ores like antimony. We understand the unique challenges of stibnite beneficiation and the importance of a customized flowsheet. Our engineers can guide you through the process, from initial ore testing to the configuration of a full production line with the right crushers, mills, and flotation cells for your specific needs.

Contact us to discuss your antimony project. We are ready to help you build an efficient and profitable processing plant based on sound engineering and a deep understanding of mineralogy.