Tail Brine Conditioning for DLE Resin Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The extracted tail brine from bromine plants has a low pH (pH<300 mV) due to residual bromine and chlorine, which affects the efficacy of direct lithium extraction (DLE) adsorption and desorption resins.
Innovation Solution
The method involves conditioning the tail brine with a mixture of sodium hydroxide or ammonium hydroxide to raise the pH to between 5.5 and 6.5, and then adding hydrazine hydrate or hydroxylamine hydrochloride to lower the oxidation-reduction potential (ORP) to less than 300 mV, thereby stabilizing the ion exchange resins used in DLE processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the tail brine is used directly in the DLE process, then the process is simpler and faster, but the ion exchange resins are degraded due to low pH and high ORP
Solution Approach 1:
The patent applies preliminary action by treating the tail brine with sodium hydroxide and hydrazine hydrate before it enters the DLE process. This pre-treatment adjusts the pH to neutral levels and reduces ORP to protect the ion exchange resins from degradation, allowing the resins to function reliably throughout the extraction process.
Solution Approach 2:
The patent uses an intermediary approach by introducing sodium hydroxide and hydrazine hydrate as protective agents between the acidic tail brine and the ion exchange resins. These chemicals act as mediators that neutralize the harmful low pH and high ORP conditions, creating a compatible environment for the resins without requiring direct contact between the brine and resin in their original states.
2Reliability
If chemical treatments are applied to adjust pH and ORP, then the resin stability is improved, but the process complexity and cost increase
Solution Approach 1:
The patent applies parameter changes by systematically adjusting the pH and ORP parameters of the tail brine through controlled addition of sodium hydroxide and hydrazine hydrate. By optimizing these chemical parameters to specific ranges (pH near neutral, ORP reduced), the process protects the resins while maintaining a relatively simple treatment protocol that can be integrated into existing DLE operations.
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 stabilizes the ion exchange resins, improving their capacity, selectivity, and longevity, thus enhancing the overall efficiency and cost-effectiveness of the lithium extraction process.
Implementation Method 1
conditioning the tail brine with a mixture of sodium hydroxide or ammonium hydroxide to raise the pH to between 5.5 and 6.5
Implementation Method 2
adding hydrazine hydrate or hydroxylamine hydrochloride to lower the oxidation-reduction potential (ORP) to less than 300 mV
Implementation Method 3
direct lithium extraction (DLE) adsorption and desorption resins
Data Source
AI summary
The present disclosure provides various characteristics for treating tail brine extracted from a bromine plant, when said brine contains residual bromine and chlorine with low pH and high ORP values that will be used in a lithium extraction production facility. The method conditions the extracted tail brine by adding either sodium hydroxide or ammonium hydroxide to bring its pH levels to between 5.5 and 6.5. The conditioned tail brine then gets pre-treated with hydrazine in either less than 70 ppm if used in combination with sodium hydroxide; or 195 ppm if used with ammonium hydroxide until the ORP levels have reached to below 100 mV. The extracted tail brine is then processed through DLE processing device having four groups of adsorption columns filled with lithium adsorption resins that, after treating the extracted tail brine, discharges the raw eluate solution to an effluent tail brine tank using an effluent tail brine pump connected to the DLE processing device.