Are you curious about how modern gold mines, facing increasingly depleted high-grade resources, extract gold with a purity of up to 99.9% from seemingly worthless low-grade ores? The answer is gold Carbon-In-Pulp (CIP). Leveraging the powerful adsorption capacity of activated carbon for gold-cyanide complexes, it is considered a core technology for gold extraction in the mining industry today. Not only can it recover over 95% of the gold, but it also integrates environmental protection into the production process while reducing investment costs by 30%. Whether you are a mining engineer, investor, or a reader interested in gold extraction technology, this article will systematically break down the core principles, applications, complete process steps, and key comparisons with other processes using CIP, helping you thoroughly understand its key advantages in gold beneficiation.
Gold Carbon-In-Pulp (CIP) utilizes activated carbon to adsorb gold from cyanide slurry. The process includes crushing and grinding, cyanide leaching, countercurrent activated carbon adsorption, high-temperature and high-pressure desorption and electrolysis, gold mud smelting, and activated carbon regeneration. CIP is suitable for low-grade oxidized gold ores, achieving recovery rates of 90%–96%, and is one of the most mainstream gold extraction technologies in the global mining industry.
Gold Carbon-In-Pulp (CIP) Overview
(1) Definition
Gold Carbon-In-Pulp (CIP) is a physicochemical adsorption process that uses activated carbon to extract gold from cyanide leaching solutions. CIP eliminates the need for filtration and washing, resulting in a simpler and more efficient process. Currently, hundreds of gold mines worldwide use the CIP process, making it a mainstream technology for processing low-grade gold ore.
(2) Core Principle
The finely ground ore is added to a cyanide solution. Gold dissolves, forming soluble complex ions. Coconut shell activated carbon possesses a dense microporous structure, which effectively adsorbs the gold complexes in the solution. The gold-loaded carbon undergoes desorption under high temperature and pressure. The gold detaches from the carbon and enters the electrolysis process, ultimately producing a high-purity gold mud product.
(3) Industries & Ores Suitable for CIP
- Flotation Gold Concentrate: After pretreatment, CIP further extracts residual gold from the concentrate.
- High-Muddy Oxide Gold Ores: High muddy content easily clogs filter equipment, while CIP eliminates the need for solid-liquid separation.
- Amalgamation/Gravity Separation Tailings: Containing considerable gold, CIP can recover residual fine gold particles.
- Low-Grade Oxide Gold Ores: Carbon-In-Pulp tech is profitable due to its high recovery rate and low cost.
Note: If the silver content is too high, it will compete for adsorption sites on activated carbon; therefore, CIP is not suitable for processing high-silver gold ores (gold-silver ratio > 1:5). Flotation or a combined process is recommended.
(4) Gold Recovery Rate Data:
- CIP Recovery Rate: 90%–96%+ (depending on ore properties)
- Gold-bearing carbon grade: 3000–10000 g/t
- Desorption Efficiency: ≥96% (high temperature and high pressure method)
- Electrolysis Efficiency: 98%+
- Gold Ingot Purity: ≥99.9%; internationally certified gold purity standard.
How Does the Gold Carbon-In-Pulp Process Work?（Step-by-Step Flow）
1. Crushing & Grinding
The ore is first coarsely crushed by a jaw crusher. Then it is fed into a cone crusher for medium and fine crushing. A vibrating screen controls the particle size of the material before it enters the grinding mill. The ball mill grinds the ore to a particle size of -200 mesh (0.074mm), achieving a content of over 85%, thus fully liberating the gold particles. Furthermore, a spiral classifier works in conjunction with the ball mill to form a closed-circuit grinding system, ultimately obtaining a uniformly sized slurry product.
2. Cyanide Leaching
Sodium cyanide is added after the ore slurry flows into the leaching tank. Air is then injected, and the mixture is continuously stirred. Gold combines with cyanide in the alkaline environment. The gold dissolves from the solid ore, forming a gold-cyanide complex that enters the solution. This process takes several hours to complete.
3. Carbon Adsorption
The slurry enters the adsorption tank and is mixed with coconut shell activated carbon. Then, the microporous structure of the activated carbon begins to capture gold in the solution. Subsequently, the slurry and carbon flow counter-currently for thorough contact. Multiple adsorption tanks operate in series to enhance efficiency. The gold-loaded carbon is then separated by a screen and sent to the next process.
4. Desorption & Electrolysis
Gold-loaded carbon enters a high-temperature, high-pressure desorption system. Under specific temperature and pressure conditions, the desorption solution elutes gold from the carbon pores. The gold-rich solution flows into the electrolytic cell, where gold ions are reduced to solid gold mud at the cathode. The entire process is relatively short, while the depleted carbon awaits regeneration.
5. Smelting
Gold mud is immersed in an acid washing tank to remove impurities. After cleaning, it is sent to a high-frequency gold melting furnace, where the gold mud is melted into a golden liquid at high temperature. The liquid gold is poured into a mold to cool and solidify. After demolding, standard gold ingots are obtained, with purity meeting the requirements of the international market.
6. Carbon Regeneration
The carbon regeneration system consists of two stages: acid washing and high-temperature roasting. After desorption, the lean carbon is first acid-washed with dilute sulfuric acid to remove inorganic scale, such as carbonates accumulated on the surface, and then sent to a rotary kiln for high-temperature thermal activation treatment. The high temperature in the kiln burns away the organic matter clogging the micropores, effectively restoring the adsorption performance of the activated carbon. After sieving to remove fine powder, it can be reused in the adsorption process.
CIP vs. Other Processes: What's the Difference?
Process | Core Principle | Applicable Ores | Main Advantages | Main Limitations |
Leaching first, then adsorption; activated carbon adsorbs gold-cyanide complexes | Oxide ores, muddy ores | High recovery rate, no filtration required | Higher equipment investment | |
Leaching and adsorption occur simultaneously | Carbonaceous gold ores | Compact process, lower investment | Higher carbon loss | |
Air bubbles carry gold-bearing minerals | Sulfide ores, polymetallic ores | Can concentrate multiple metals | High reagent cost | |
Separation based on specific gravity difference | Placer gold, coarse gold | No chemical pollution | Poor recovery of fine gold |
Key Advantages of the CIP Process
√ High Recovery Rate: CIP can efficiently process low-grade gold ore. Activated carbon has a strong adsorption capacity. Even lean ore can achieve considerable recovery.
√ No Solid-Liquid Separation Required: Eliminating the need for filtration and washing equipment, investment and maintenance costs are simultaneously reduced.
√ Low Production Costs: Compared to other gold processing technologies (flotation, gravity separation), the carbon-in-pulp process has significant advantages in reagent and energy consumption, resulting in substantial long-term economic benefits.
√ Flexible Operation: From pilot line to industrial production, the CIP system can flexibly adjust its capacity according to actual needs, facilitating project implementation at different stages.
√ Environmentally Friendly Closed-Loop System: The complete recycling system significantly reduces wastewater discharge, while waste heat recovery technology effectively reduces energy consumption, meeting modern environmental standards.
Conclusion
Gold carbon-in-pulp (CIP) technology, with its core advantages of high recovery rate, low investment cost, and flexible production scale, has become the optimal choice for modern gold extraction. From ore crushing to gold ingot production, six interconnected steps, each embodying the profound experience of hydrometallurgy, further enhance its environmental and energy-saving characteristics, aligning with the trend of sustainable development in the mining industry and bringing investors a win-win situation in terms of both economic and environmental benefits. JXSC has been deeply involved in the gold beneficiation field for many years and possesses extensive experience in gold CIP plant design and equipment matching. Feel free to contact us anytime; we can provide customized gold processing solutions based on your ore characteristics and production capacity requirements.