Industrial Types of Gold Deposits and Beneficiation Technologies in China

Introduction

Gold deposits, as critical precious metal resources, are widely used in finance, electronics, and aerospace. China hosts diverse gold deposit types, each with unique ore characteristics and beneficiation challenges. Based on industrial classifications, this article systematically discusses the ore features and processing technologies for quartz vein-type, mylonite-type, and Carlin-type deposits, supported by case studies, to provide insights into efficient gold resource utilization.

1. Industrial Types and Ore Characteristics

China’s gold deposits are categorized into the following major types (Table 1):

1. Quartz Vein-Type Deposits

Represented by the Linglong-style deposits in Shandong, these ores feature quartz content >60% and fine-grained native gold associated with pyrite. Key challenges include sulfide-gold dissociation and sulfur-gold separation.

2. Mylonite-Type Deposits

Formed under high temperature-pressure conditions, these ores (e.g., Hetai Gold Mine) contain ultra-fine gold (<0.074 mm) encapsulated in quartz, requiring ultra-fine grinding for liberation.

3. Carlin-Type (Fine-Disseminated) Deposits

Characterized by sub-microscopic gold (<1 μm) hosted in pyrite or clay minerals, with high arsenic and carbon content. Direct cyanidation yields <5% recovery, necessitating pre-treatment (e.g., bio-oxidation).

4. Altered Cataclasite-Type Deposits

Large-scale deposits (e.g., Xincheng Gold Mine) with coarse gold but high slime content. Washing and classified flotation mitigate slime interference.

5. Lateritic and Gossan-Type Deposits

Highly oxidized with clay-rich matrices. Agglomerated heap leaching improves permeability, achieving >90% gold recovery.

6. Skarn and Breccia-Type Deposits

Skarn ores require multi-metal recovery; breccia deposits (e.g., Zijinshan) control cyanide concentration to reduce copper interference.

2. Beneficiation Processes and Case Studies

1. Quartz Vein-Type: Flotation-Cyanidation

Case: Inner Mongolia Low-Sulfide Deposit

• Ore Features: 2.58 g/t Au, low      impurities.

• Process: Whole-ore cyanidation      (-0.074 mm 85%, NaCN 4 kg/t) achieves 91.86% recovery.

• Key Points: Fine grinding and      alkaline conditions (pH=11).

2. Mylonite-Type: Ultra-Fine Grinding-CIL

Case: Hetai Gold Mine

• Ore Features: 76.28% gold      encapsulated in quartz.

• Process: Two-stage cyanidation      followed by CIL, 83% -0.074 mm grinding, 92% recovery.

• Key Points: HP300 crusher reduces      energy consumption.

3. Carlin-Type: Bio-Oxidation-Cyanidation

Case: Yunnan Carlin-Type Ore

• Ore Features: Sub-microscopic gold      in pyrite, carbonaceous matter.

• Process: 6-month bio-oxidation      pre-treatment increases recovery from 5% to 65.5%.

• Key Points: Acidithiobacillus ferrooxidans enhances      sulfide oxidation.

4. Lateritic-Type: Gravity-Cyanidation

Case: Cenozoic Lateritic Deposit

• Ore Features: Uneven gold      distribution, high clay content.

• Process: Falcon concentrator (300G)      recovers 86.09% gold; tailings leached via cyanidation.

5. Skarn-Type: Amalgamation-Flotation

Case: Yinan Gold Mine

• Ore Features: Coarse gold with      Cu-Pb-Zn sulfides.

• Process: Amalgamation for coarse      gold, flotation for Cu/S concentrates, >85% recovery.

3. Future Trends in Gold Beneficiation

1. Pre-Treatment Innovations

• Bio-Oxidation: Eco-friendly for      arsenic-rich ores.

• Microwave Technology: Rapid      decomposition of mineral.

1. Green Leaching Reagents

• Thiosulfate: Cyanide alternative      for Cu/As-bearing ores.

1. Automation & Intelligence

• AI-Driven Control: Optimizes      grinding and flotation parameters.

1. Resource Integration

• Tailings Reprocessing: Recovers      residual gold and by-products.

4. Conclusions and Recommendations

China’s complex gold resources demand tailored beneficiation strategies: optimizing sulfur-gold separation for quartz veins, preventing over-grinding in mylonites, and advancing pre-treatment for Carlin-type ores. Future progress hinges on technological innovation (e.g., biohydrometallurgy) and interdisciplinary collaboration to enhance economic and environmental sustainability.