Gypsum Removal from Leach Solution via Indirect Cooling
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Solution Overview
Problem
The presence of gypsum in calcium-containing leach solutions during metal leaching processes leads to equipment blockages, reduced energy efficiency, and lower production quality due to its low solubility and tendency to precipitate, causing scaling issues and maintenance challenges in solvent extraction processes.
Innovation Solution
A method involving indirect cooling of the calcium-containing pregnant leach solution with a gypsum-depleted solution, followed by further cooling and precipitation in a cooling device, utilizing a heat exchanger to optimize temperature control and prevent excessive gypsum formation, and a thickener to separate gypsum, thereby reducing gypsum content and improving process efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gypsum is removed from the leach solution, then equipment blockages and scaling are prevented, but additional processing steps and equipment are required
Solution Approach 1:
The patent applies preliminary action by cooling the pregnant leach solution before the solvent extraction process to precipitate gypsum in advance. The solution is cooled to a temperature between 10-30°C in a first cooling step, causing gypsum to crystallize and be removed via filtration or settling, preventing subsequent equipment blockages and scaling issues during extraction operations.
Solution Approach 2:
The patent extracts the harmful gypsum component from the pregnant leach solution through a dedicated cooling and precipitation step. By separating gypsum removal as an independent preprocessing operation, the harmful substance is extracted from the solution stream before it enters the solvent extraction system, ensuring reliable operation of extraction equipment.
2Productivity
If the leach solution is cooled to precipitate gypsum, then gypsum removal efficiency is improved, but energy is consumed for cooling
Solution Approach 1:
The patent converts the harmful effect of low temperature (which would normally require energy input to achieve) into a beneficial process by utilizing the natural temperature difference between the hot pregnant leach solution and the environment. The solution is cooled passively or with minimal energy input to a temperature range (10-30°C) that optimally precipitates gypsum, transforming a potential energy cost into an efficient separation process.
Solution Approach 2:
The patent changes the temperature parameter of the pregnant leach solution to optimize gypsum precipitation. By controlling the temperature within the specific range of 10-30°C, the solubility of gypsum is reduced, causing it to precipitate efficiently. This parameter change enables high removal efficiency while managing energy consumption through optimized cooling conditions.
3Use of energy by stationary object
If heat exchangers are used to cool the pregnant leach solution, then cooling efficiency is improved, but equipment complexity and maintenance requirements increase
Solution Approach 1:
The patent introduces an intermediary cooling medium (such as process water or ambient air) to transfer heat from the pregnant leach solution without requiring complex direct cooling systems. The heat exchanger uses this intermediary to indirectly cool the solution, simplifying the overall system design while maintaining efficient heat transfer and reducing maintenance requirements compared to direct cooling methods.
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
This approach effectively reduces gypsum-related maintenance and downtime, enhances product quality, and optimizes energy use by preventing heat wastage, allowing for efficient gypsum removal before solvent extraction, resulting in improved operational efficiency and reduced costs.
Implementation Method 1
cooling a calcium-containing pregnant leach solution by indirectly contacting the calcium-containing pregnant leach solution with a gypsum-depleted pregnant leach solution
Implementation Method 2
cooling the cooled pregnant leach solution in a cooling device to obtain a further cooled pregnant leach solution
Implementation Method 3
precipitating gypsum from the further cooled pregnant leach solution to obtain the gypsum-depleted pregnant leach solution
Implementation Method 4
precipitating the gypsum into particles suitable for thickening
Implementation Method 5
a thickener for precipitating gypsum from the further cooled pregnant leach solution
Data Source
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Figure 2
AI summary
A method is disclosed for removing gypsum from calcium-containing material, wherein the method comprises cooling a calcium-containing pregnant leach solution (10) by indirectly contacting the calcium-containing pregnant leach solution (10) with a gypsum-depleted pregnant leach solution (11) to obtain a cooled pregnant leach solution (19). The cooled pregnant leach solution (19) is cooled in a cooling device (13) to obtain a further cooled pregnant leach solution (12). Gypsum is precipitated from the further cooled pregnant leach solution (12) to obtain the gypsum-depleted pregnant leach solution (11).