Antimony Processing Plant Design and Cost Analysis

Antimony-design-processing-plant

This article provides a comprehensive overview of antimony processing plant design principles, typical process flowsheets, key equipment selection, and a detailed cost analysis, helping investors and project developers evaluate technical feasibility and capital requirements.

1.1 Common Antimony Ore Types

Antimony occurs mainly in the following forms:

• Sulfide ores: Stibnite (Sb₂S₃), the most economically important mineral

• Oxide ores: Cervantite, valentinite (less common)

• Complex polymetallic ores: Associated with gold, mercury, arsenic, or lead

Among these, antimony sulfide ores dominate commercial mining, and their processing typically relies on gravity separation, flotation, or a combination of both.

1.2 Processing Challenges

Key technical challenges in antimony processing include:

• Fine-grained mineral dissemination

• High density but brittle mineral structure

• Sensitivity to over-grinding

• Environmental risks from arsenic and sulfur

These factors must be addressed during plant design to achieve high recovery, stable operation, and regulatory compliance.

A well-designed antimony processing plant must balance metallurgical performance, capital efficiency, and operational simplicity. The following principles guide effective plant design.

2.1 Ore Characterization as the Design Foundation

Before any process design, detailed test work is essential, including:

• Chemical composition analysis

• Mineralogical studies (liberation size, associations)

• Gravity and flotation test results

• Grindability and abrasiveness tests

Accurate ore characterization directly determines the process route, equipment sizing, and cost estimation accuracy.

2.2 Process Route Selection

The most common antimony processing routes include:

1. Gravity separation flowsheet

2. Flotation-based flowsheet

3. Combined gravity + flotation flowsheet

Gravity separation is preferred when stibnite shows sufficient liberation at coarse sizes, while flotation is used for fine or complex ores.

3.1 Crushing and Screening Section

The processing plant begins with primary and secondary crushing to reduce run-of-mine (ROM) ore to manageable sizes.

• Jaw crusher for primary crushing

• Cone or impact crusher for secondary crushing

• Vibrating screens for size classification

Design considerations:

• Avoid excessive fines generation

• Ensure stable feed size for grinding

3.2 Grinding and Classification

Grinding is one of the most critical stages in antimony processing.

Common configurations:

• Ball mill + hydrocyclone

• Rod mill + ball mill (for coarse liberation)

Key design objectives:

• Achieve optimal liberation without over-grinding

• Protect stibnite from sliming

• Control particle size distribution precisely

Energy consumption in this stage significantly impacts operating costs.

3.3 Gravity Separation Circuit

For coarse and medium-grained stibnite, gravity separation offers:

• Low operating cost

• Simple flowsheet

• High selectivity

Typical gravity equipment includes:

• Jig separators

• Spiral concentrators

• Shaking tables

Gravity concentrates are often upgraded further or directly sold if grade meets market requirements.

3.4 Flotation Circuit

For fine-grained or complex antimony ores, flotation is essential.

Flotation design includes:

• Rougher, scavenger, and cleaner stages

• pH control and reagent dosing

• Selective collectors and depressants

Flotation allows higher recovery but increases capital and operating costs due to reagent consumption and process control requirements.

3.5 Concentrate Dewatering and Tailings Management

Final antimony concentrate is processed through:

• Thickener

• Filter press or vacuum filter

• Drying (if required by downstream processing)

Tailings management must comply with environmental regulations, often requiring:

• Tailings thickening

• Lined tailings storage facilities

• Water recycling systems

Plant capacity is typically defined in tons per day (TPD) and must align with mine production plans.

Typical capacity ranges:

• Small-scale plant: 100–300 TPD

• Medium-scale plant: 500–1,000 TPD

• Large-scale plant: 2,000+ TPD

Capacity selection affects:

• Equipment size and redundancy

• Capital expenditure (CAPEX)

• Unit processing cost

Modular or phased expansion designs are often recommended to reduce upfront risk.

5.1 Major CAPEX Components

Antimony processing plant capital cost typically includes:

1. Process equipment

• Crushers, mills, flotation machines, gravity separators

2. Auxiliary systems

• Pumps, compressors, reagent systems

3. Civil works

• Foundations, buildings, structural steel

4. Electrical and control systems

• MCCs, automation, instrumentation

5. Installation and commissioning

• Mechanical and electrical installation

6. Engineering and project management

5.2 Typical CAPEX Range

While costs vary by region and project complexity, approximate ranges are:

• Small plant (300 TPD): USD 3–6 million

• Medium plant (1,000 TPD): USD 8–15 million

• Large plant (2,000+ TPD): USD 20–40 million

Factors influencing capital cost include:

• Ore hardness and complexity

• Degree of automation

• Environmental protection requirements

• Local labor and construction costs

Operating cost determines long-term project profitability.

6.1 Key OPEX Components

1. Energy consumption

• Crushing and grinding dominate power usage

2. Consumables

• Grinding media

• Flotation reagents

3. Labor

• Operators, technicians, management

4. Maintenance

• Spare parts and wear components

5. Water and tailings management

6.2 Typical Operating Cost Range

Depending on plant scale and process complexity:

• Gravity-dominated flowsheet: USD 10–18 per ton of ore

• Flotation-based flowsheet: USD 18–30 per ton of ore

Reducing grinding energy and reagent consumption is the most effective way to control OPEX.

Antimony processing plant design and cost analysis require a comprehensive understanding of ore characteristics, processing technologies, and economic constraints. From crushing and grinding to gravity separation and flotation, each design decision directly impacts capital investment, operating cost, and overall project profitability.

A well-designed antimony processing plant—supported by thorough test work, realistic cost estimation, and experienced engineering partners—can achieve high recovery, stable operation, and attractive financial returns. As global demand for antimony continues to grow, professionally designed and cost-optimized processing plants will play a crucial role in ensuring sustainable and competitive production.