Solution Mining Sodium Carbonate Bicarbonate Ore
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Solution Overview
Problem
The solution mining of sodium (bi)carbonate-containing ores, such as trona and Wegscheiderite, faces challenges due to incongruent dissolution, leading to 'bicarb blinding' which clogs the dissolving face and reduces the recovery of sodium carbonate values, requiring continuous use of costly alkalis like sodium hydroxide to maintain solubility.
Innovation Solution
A method involving two solution mining phases with aqueous solvents differing in pH, hydroxide concentration, or temperature to manage the solubility and prevent redeposition of sodium bicarbonate, allowing for the recovery of alkali values by dissolving sodium bicarbonate and converting it to sodium carbonate, thereby maintaining effective solvent action and reducing clogging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If solution mining is used to extract sodium carbonate and bicarbonate from subterranean deposits, then alkali values can be recovered, but incongruent dissolution causes sodium bicarbonate to redeposit and clog the dissolving face, reducing recovery efficiency
Solution Approach 1:
The solution mining process is divided into two distinct phases: a first phase using a first aqueous solvent and a second phase using a second aqueous solvent with different characteristics (higher pH, hydroxide concentration, and/or temperature). This segmentation allows each phase to target different aspects of the dissolution process, preventing bicarbonate redeposition while maintaining high recovery rates.
Solution Approach 2:
The first aqueous solvent is introduced to initiate dissolution and prepare the ore face before the second aqueous solvent is applied. This preliminary action creates favorable conditions for the second phase to operate more effectively, maximizing alkali recovery while preventing clogging.
2Reliability
If continuous use of costly alkalis like sodium hydroxide is applied to maintain solubility, then bicarbonate redeposition can be prevented, but operational costs increase significantly
Solution Approach 1:
The invention changes key parameters of the aqueous solvent between two phases: pH, hydroxide concentration, and temperature. The second phase uses a solvent with higher values for these parameters, which naturally prevents bicarbonate redeposition without requiring continuous addition of costly alkalis like sodium hydroxide, thereby reducing operational costs.
3Ease of operation
If a single aqueous solvent is used for solution mining, then the process is simpler to operate, but it cannot effectively prevent sodium bicarbonate redeposition due to incongruent dissolution
Solution Approach 1:
The mining process is segmented into two phases with different solvent characteristics. While this adds a step to the process, each phase is clearly defined and executed sequentially, maintaining operational simplicity while effectively preventing clogging through the complementary actions of the two phases.
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 enhances the recovery of alkali values by maintaining sodium bicarbonate concentration below saturation levels, preventing clogging, and reducing the economic burden of continuous alkali use, thereby improving the efficiency and cost-effectiveness of the solution mining process.
Implementation Method 1
dissolving in situ at least a portion of ore from an ore face of the cavity into a first aqueous solvent to form a first liquor comprising sodium carbonate
Implementation Method 2
said second aqueous solvent having a parameter selected from the group consisting of surface pH, surface hydroxide concentration, surface temperature, and any combinations thereof, which has a higher value than that of the first aqueous solvent
Data Source
Figure 1a~1d
Figure 2a~2b
Figure 2c~2d
AI summary
A solution mining method for recovering alkali values from at least one cavity of an underground ore formation comprising a sodium (bi)carbonate double-salt (such as trona or wegscheiderite); a manufacturing process using such method to make at least one sodium-based product; and a sodium-based product obtained by said manufacturing process. The solution mining method comprises a first phase (a) in which the incongruent double-salt is dissolved from an ore face in a first solvent and a second phase (b) in which a second aqueous solvent having a higher pH, hydroxide content, and/or temperature is used. Under certain conditions, any sodium bicarbonate deposited on the ore face during the first phase (a) may be dissolved into the second solvent and partly or completely converted in situ to sodium carbonate. The method further comprises withdrawing a liquor resulting from either phase to the ground surface, optionally recycling some liquor to the cavity; and passing some liquor through a crystallizer, a reactor, and/or an electrodialyser, to form at least one sodium-based product which is recovered.