Two-Stage Nanofiltration for Boric Acid Purification
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Solution Overview
Problem
Existing methods for purifying boric acid, such as ion exchange resin technology, are inefficient due to high costs, low throughput, and rapid pollution, which fails to effectively remove impurities like sodium, lithium, calcium, magnesium, iron, sulfate, and chloride.
Innovation Solution
A two-stage nanofiltration process is employed, where a heated boric acid solution is first passed through a first nanofiltration membrane and then the permeate is passed through a second nanofiltration membrane, achieving a boric acid solution with at least 10 wt% boric acid and reduced impurities such as sodium, calcium, lithium, sulfur, and silicon to less than 5 ppm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ion exchange resin technology is used for purifying boric acid, then separation performance is achieved, but the process is quickly polluted, compromising separation performance
Solution Approach 1:
The patent replaces expensive ion exchange resin with nanofiltration membranes that can be easily replaced. The membranes are designed for single-use or limited-use, eliminating the need for costly regeneration and maintaining consistent performance without the pollution issues affecting resin service life.
Solution Approach 2:
The patent changes the separation mechanism from ion exchange to nanofiltration, utilizing membrane pore size and surface properties to separate impurities. This parameter change in the separation mechanism fundamentally resolves the pollution and service life issues of ion exchange resin.
2Manufacturing precision
If ion exchange resin is used for purifying boric acid, then impurities are removed, but high cost for regeneration fluid is required
Solution Approach 1:
The nanofiltration membranes replace expensive regeneration fluid requirements. Once the membranes become polluted or degraded, they are simply replaced rather than regenerated, eliminating the continuous cost burden of regeneration fluids while maintaining high purification levels.
Solution Approach 2:
The patent extracts and removes impurities through the nanofiltration membrane during the filtration process, separating them from the boric acid solution. This extraction mechanism eliminates the need for subsequent regeneration steps and associated costs.
3Reliability
If ion exchange resin technology is used for purifying boric acid, then separation is achieved, but low throughput is observed
Solution Approach 1:
The patent changes the separation mechanism from ion exchange to nanofiltration, which allows for higher flux and throughput. The membrane-based approach enables faster separation rates while maintaining effective impurity removal, thus improving productivity without sacrificing separation performance.
4Manufacturing precision
If conventional purification methods are used for boric acid, then impurities are removed, but high cost and environmental harm are incurred
Solution Approach 1:
The use of disposable nanofiltration membranes eliminates the need for harmful regeneration chemicals. The membranes are replaced rather than regenerated, avoiding the environmental harm associated with chemical regeneration while maintaining effective purification levels.
Solution Approach 2:
The patent converts the potential harm of membrane pollution into a benefit by designing for easy replacement. This approach eliminates harmful regeneration chemicals while maintaining purification effectiveness, turning what would be a waste problem into an environmentally friendly disposal solution.
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 process significantly reduces impurity levels, increases the economic value of boric acid, and is more cost-effective and environmentally friendly compared to conventional methods, while maintaining high boric acid concentration.
Implementation Method 1
passing the heated boric acid solution through a first nanofiltration membrane at a pressure from 300 psi to 500 psi to form a first heated boron permeate
Data Source
AI summary
The present disclosure is directed to a process. In an embodiment, the process includes providing a boric acid solution composed of from 10 wt % to 25 wt % boric acid at a temperature from 60° C. to less than 100° C. to form a heated boric acid solution. The process includes first passing the heated boric acid solution through a first nanofiltration membrane at a pressure from 300 psi to 500 psi to form a first heated boron permeate and second passing the first heated boron permeate through a second nanofiltration membrane at a pressure from 300 psi to 500 psi and forming a second heated boron permeate. The second heated boron permeate is composed of at least 10 wt % boric acid, less than 5 ppm sodium, and less than 5 ppm of a component selected from calcium, lithium, sulfur, and silicon.