PANDA vs. Sodium Cyanide: A Comparative Study in Carbon-in-Pulp (CIP) Gold Extraction
Achieving 91% Gold Recovery with an Eco-Friendly Alternative at a 400t/d Plant
Introduction
Replacing highly toxic sodium cyanide (NaCN) in gold mining has long been an industry goal, but performance often comes at a cost. Can an eco-friendly alternative truly match the efficiency of traditional cyanidation? A comprehensive study conducted at Suxian Zhipeng Mining Co., Ltd. provides a definitive answer. This report details the laboratory and industrial application tests of the PANDA environmentally friendly gold dressing agent, demonstrating how it achieved a gold recovery rate of over 91% in a full-scale Carbon-in-Pulp (CIP) operation.
Background: The Challenge of Toxic Reagents
Suxian Zhipeng Mining, with a daily processing capacity of 400 tons, traditionally utilized the all-mud cyanide carbon slurry process. While the ore composition—limonitized fine-grained gold ore—is relatively simple with a high oxidation rate, the use of sodium cyanide posed significant safety and environmental risks. To address these challenges, the company initiated a transition to PANDA, a low-toxicity alternative, to evaluate its feasibility in a real-world production environment.
Phase 1: Laboratory Simulation Tests
Before full-scale implementation, a series of controlled laboratory tests were conducted to compare PANDA against sodium cyanide under identical conditions (40% slurry concentration, 88% grinding fineness, pH 11-12). The tests explored two different aeration methods: standard air blowing and oxygen-enriched stirring.
1. Performance Under Air Stirring
In tests using standard air agitation (Groups 1 & 2), PANDA demonstrated performance virtually identical to sodium cyanide. As shown in the data below, the leaching rates were comparable, proving that for standard aeration processes, PANDA is a direct substitute.
Key Finding: Under air stirring, PANDA achieved leaching rates of 86.96% and 84.24%, closely matching the 86.59% and 83.25% achieved by sodium cyanide.
2. The Oxygen Sensitivity Factor
Interestingly, tests using oxygen-enriched stirring (Groups 3 & 4) revealed a critical distinction. PANDA's performance was slightly inferior to sodium cyanide under high-concentration oxygen conditions. Analysis suggests this is due to the oxidation and decomposition of thiourea (a key active ingredient in FKN) when exposed to high levels of oxygen. This finding indicates that PANDA is best optimized for standard air-filled leaching processes rather than pure oxygen environments.
Phase 2: Industrial Application at 400t/d Scale
Following the lab tests, Zhipeng Mining implemented PANDA in their industrial production line from March to August 2018. The plant operated under its original process conditions using air-filled leaching tanks. The results were highly successful.
Consistent High Recovery Rates
Over a six-month period, the plant maintained an average gold leaching rate of approximately 91%. For instance, in March 2018, the plant achieved a leaching rate of 91.29% with a gold adsorption rate of 99.80%. These figures confirm that PANDA can completely replace sodium cyanide without compromising recovery efficiency.
Economic and Operational Benefits
Beyond environmental safety, the switch to PANDA offered economic advantages. The reagent consumption ranged between 200g/t and 260g/t, and under local pricing conditions, the overall economics of using PANDA proved to be superior to sodium cyanide. Furthermore, PANDA eliminates the strict storage and transportation regulations associated with hazardous cyanide chemicals.
Conclusion: A Viable Path to Green Mining
The industrial trial at Suxian Zhipeng Mining conclusively proves that the PANDA environmentally friendly gold dressing agent is a technically and economically viable replacement for sodium cyanide in CIP processes. While it requires standard air aeration rather than oxygen enrichment, it delivers consistent recovery rates (>90%) and significantly reduces the environmental footprint of gold extraction. For mining operations looking to improve safety and sustainability without sacrificing yield, PANDA presents a compelling solution.
Related Catalogues:
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GOLD RECOVERY OPTIMIZATION SYSTEM
CYANIDE MANAGEMENT & ENVIRONMENTAL COMPLIANCE SYSTEM
FAQ for A Comparative Study in Carbon-in-Leach (CIL) Gold Extraction
1. Can PANDA gold leaching agent completely replace sodium cyanide in a CIL plant?
Yes. The industrial case study at Suxian Zhipeng Mining (400t/d capacity) demonstrated that PANDA can completely replace sodium cyanide. Over a six-month production period, PANDA achieved a gold leaching rate of over 91% and an adsorption rate of 99.8%, matching the performance of traditional cyanidation without requiring changes to the existing process flow.
2. Is PANDA suitable for oxygen-enriched leaching processes?
Based on laboratory tests, PANDA is not recommended for oxygen-enriched environments. The test results showed that high concentrations of oxygen can cause the thiourea in PANDA to oxidize and decompose, reducing its gold-dissolving efficiency. PANDA performs optimally under standard air-stirring (air-filled) conditions, where it matches the recovery rates of sodium cyanide.
3. What are the economic benefits of using PANDA compared to cyanide?
FKN offers dual economic benefits. First, it eliminates the high costs associated with the strict transportation, storage, and safety management required for highly toxic sodium cyanide. Second, the industrial test showed a reagent consumption of 200-260g/t, and under local pricing, the overall operating cost was lower than that of sodium cyanide while maintaining high recovery rates.
4. What type of ore is best suited for the PANDA leaching agent?
PANDA is highly effective for ores with simple mineral compositions, such as limonitized fine-grained gold ores with high oxidation rates and low levels of harmful impurities. The case study showed excellent results on ore where gold exists primarily as natural gold embedded among limonite, quartz, and calcite grains.
5. Does using PANDA require modifying the existing Carbon-in-Pulp (CIP) equipment?
No. The industrial application at Zhipeng Mining was conducted under the original industrial process conditions