Selective Mining of Potash Using Brine Saturation and Trigeneration
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Solution Overview
Problem
Conventional solution mining processes for sylvinite ore require high energy and water due to the need for pumping and heating, leading to increased costs and inefficiencies, particularly in the separation of KCl and NaCl, with excessive NaCl mining and energy consumption in cooling crystallization processes.
Innovation Solution
A method utilizing superheated steam to generate electricity and produce chilled water through an absorption chiller, reducing brine circulation rates and energy requirements by leveraging trigeneration of steam, electrical, and chilled water utilities for enhanced mineral recovery, specifically using a 4-stage cooling crystallizer system and absorption chiller to create chilled water for efficient KCl recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional solution mining uses pure water injection for primary mining, then KCl concentration difference is large and circulation rate is reduced, but excessive NaCl is mined along with KCl requiring evaporation and separation equipment
Solution Approach 1:
The patent changes the composition parameter of the injection solution from pure water to a brine solution with specific NaCl concentration (23-26 wt%) and controlled KCl concentration (0-4 wt%). This parameter change allows the solution to be saturated with NaCl but under-saturated with KCl, enabling selective mining where NaCl remains in the cavern while KCl is dissolved and recovered, thus reducing unwanted NaCl mining while maintaining efficient circulation rates
Solution Approach 2:
The patent applies different concentration characteristics to different minerals in the same injection solution. The brine is designed to be saturated with respect to NaCl (preventing its dissolution) while being under-saturated with respect to KCl (allowing its dissolution). This local quality differentiation enables selective mining of KCl while leaving NaCl behind, resolving the contradiction between maintaining circulation rate and preventing excessive NaCl mining
2Productivity
If solution mining requires heating and pumping of injection water, then mineral recovery is achieved, but energy consumption increases significantly
Solution Approach 1:
The patent merges the mining function with power generation by injecting brine that drives turbines located in the solution mine caverns. The flowing brine simultaneously performs mining operations and generates electrical power, reducing the net energy consumption of the mining process while maintaining mineral recovery productivity
Solution Approach 2:
The patent implements self-service by using the mine's own production brine to generate power. The brine that flows from the caverns after mineral extraction is directed through turbines to generate electricity, allowing the mining operation to partially power itself and reducing external energy requirements for pumping and heating
3Loss of substance
If secondary mining is used to mine principally just KCl by injecting NaCl-saturated brine, then unwanted NaCl is left in the mine, but primary mining must continue to create caverns for secondary mining
Solution Approach 1:
The patent inverts the conventional sequence by making selective mining (traditionally secondary) the primary and only mining operation. Instead of using selective mining only after creating caverns with primary mining, the patent applies selective mining from the beginning using horizontal wells to create caverns directly with NaCl-saturated brine injection, eliminating the need for dual mining operations while achieving both goals simultaneously
4Productivity
If cooling crystallization is used to recover KCl, then mineral recovery is achieved, but water consumption and energy for cooling increase
Solution Approach 1:
The patent implements feedback by using the cold brine returned from the cooling crystallization process and directly returning it to the caverns for injection. This cold brine serves dual purposes: it provides cooling for crystallization and then is reused as injection fluid, reducing the need for additional cooling water and improving the overall efficiency of the mining and recovery process
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 decreases energy and water consumption, improves mineral recovery efficiency, and reduces operational costs by optimizing brine circulation rates and mineral solubility limits, achieving a 30% reduction in flowrate and associated energy savings, while selectively mining KCl and minimizing unwanted NaCl extraction.
Implementation Method 1
creating superheated steam using a steam boiler
Implementation Method 2
passing the superheated steam through a turbine/generator to generate electricity
Implementation Method 3
reheating the steam exiting the turbine/generator to saturation with a steam reheater; and using the saturated steam with an absorption chiller to create chilled water
Implementation Method 4
recovering minerals using the chilled water in a cooling crystallizer system
Data Source
AI summary
Some embodiments of the present disclosure include a method and method for recovery of solution mined minerals. The method may include creating superheated steam using a steam boiler; passing the superheated steam through a turbine/generator to generate electricity; reheating the steam exiting the turbine/generator to saturation with a steam reheater; using the saturated steam with an absorption chiller to create chilled water; and recovering minerals using the chilled water in a cooling crystallizer system. In embodiments, the method and system may be used to recover minerals, such as potash (KCl), washing soda (Na2CO3.10H2O); nahcolite (NaHCO3); and glauber salt (NaSO4.10H2O). The method may utilize the trigeneration of steam, electrical, and chilled water utilities, which may be used for a recovery process.