Screen Pipe Filter Bed for Gold Leaching Dewatering
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Solution Overview
Problem
Conventional leaching processes for recovering metals like gold from ores require finely ground particles and high energy consumption, as they rely on continuous agitation leaching with limitations in particle size and retention time, leading to inefficient metal recovery and increased processing costs.
Innovation Solution
A method and apparatus for liquid/solid separation using a tank with an agitator and a screen pipe to form a graded filter bed, allowing for the separation of particles up to 2 mm in diameter, with high cyanide concentrations and variable speed agitation, enabling efficient leaching of gold and other metals by forming a filter bed to drain the solution, reducing component wear and processing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous agitation leaching is used with finely ground particles, then metal recovery is improved, but energy consumption increases and processing time increases
Solution Approach 1:
The patent implements periodic agitation cycles where the agitator operates intermittently rather than continuously. The agitator is activated for specific durations to maintain suspension and facilitate leaching, then stopped to allow settling and filtration. This periodic operation reduces energy consumption while maintaining effective metal recovery through optimized agitation intervals.
Solution Approach 2:
The patent changes the operational parameters by allowing variable particle sizes (including coarse particles up to 2mm) instead of requiring fine grinding. It uses controlled agitation speeds and durations, adjusts cyanide concentration levels, and modifies retention time parameters to achieve effective leaching without the need for extensive fine particle processing, thereby reducing energy requirements.
2Reliability
If continuous agitation leaching is used with finely ground particles, then metal recovery is improved, but processing time increases
Solution Approach 1:
The periodic agitation pattern allows the system to cycle through suspension, leaching, and filtration phases. By stopping agitation during filtration phases, the system achieves rapid solid-liquid separation without requiring continuous processing time, thus reducing overall processing duration while maintaining recovery efficiency.
Solution Approach 2:
The patent employs preliminary classification to separate particles by size before leaching. Coarse particles are removed preliminarily, and only suitable particles undergo leaching. This preliminary action optimizes the leaching process efficiency and reduces the time required for effective metal recovery by focusing resources on the most suitable material.
3Reliability
If fine particle size is used for agitation leaching, then metal recovery is improved, but grinding cost increases
Solution Approach 1:
The patent fundamentally changes the particle size parameter acceptance, allowing coarse particles up to 2mm to be processed directly without fine grinding. This parameter change eliminates the expensive grinding step while maintaining effective leaching performance through optimized agitation and filtration processes, directly reducing grinding costs.
Solution Approach 2:
The patent employs disposable or easily replaceable filtration media and screen pipes that can be quickly replaced when clogged or worn. This approach is more economical than investing in expensive grinding equipment and maintenance, allowing the system to process coarse particles cost-effectively without requiring durable, expensive grinding infrastructure.
4Reliability
If high cyanide concentrations are used, then metal recovery is improved, but safety risks increase
Solution Approach 1:
The patent replaces continuous mechanical agitation with periodic agitation combined with gravity-driven filtration and decantation. This substitution reduces the overall process time and cyanide exposure duration, thereby mitigating safety risks associated with high cyanide concentrations while maintaining effective metal recovery through optimized periodic processing cycles.
Solution Approach 2:
The patent ensures continuous useful action through automated monitoring and control systems that maintain optimal cyanide concentrations throughout the processing cycle. The system continuously adjusts cyanide addition rates, agitation timing, and filtration parameters to maximize recovery while minimizing safety risks through precise, continuous control rather than batch processing with higher peak concentrations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method achieves a 99.3% gold recovery efficiency with larger particle sizes and higher cyanide concentrations, reducing processing time and energy consumption while maintaining effective liquid/solid separation, making it scalable and cost-effective for both small and large-scale operations.
Implementation Method 1
an agitator suspended within the tank for forming a suspension of the particles in said liquid
Implementation Method 2
the tank having a lower section for formation of a filter bed to drain liquid from the tank
Implementation Method 3
forming a graded filter bed to drain liquid from the tank
Implementation Method 4
a screen pipe extending upwardly through the filter bed area and communicating with the output passage to receive at its upper end a flow of liquid from above the lower section which is carried downwardly to flow out through the filter bed section to the outlet passage
Data Source
AI summary
Methods and apparatus for liquid/solid separation for use in applications such as dewatering fine particulate solids, and recovery of valuable metals from ore in a leaching process are provided. One application relates to methods of agitation leaching of metals such as gold from gold-bearing feedstock. A slurry is formed in a tank by agitation, and allowed to settle. A filter bed forms to drain the liquid from the tank, and a vertical screen pipe such as a well point addresses the formation of an impervious film on the upper surface of the filter bed.