Purified Silicic Acid via Chelating Resin Ion Exchange
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Solution Overview
Problem
Conventional methods for producing high-purity colloidal silica using water glass as a raw material require multiple purification steps and involve the use of costly or corrosive substances, such as hydrogen peroxide and hydrochloric acid.
Innovation Solution
A method involving the passage of an aqueous solution of alkaline silicate through a polyamine-type chelating resin followed by a hydrogen-type cation exchange resin, reducing the number of purification steps and eliminating the need for unnecessary additives, thereby achieving a purified aqueous solution of silicic acid with lower metal impurities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional purification methods using multiple steps including strong oxidizers and strong acids are used, then metal impurities are effectively removed, but device corrosion increases and production cost increases
Solution Approach 1:
The invention changes the chemical parameters of the purification system by replacing strong oxidizers and strong acids with a two-stage ion exchange process using cation exchange resin and anion exchange resin. This parameter change eliminates corrosive substances while maintaining effective metal impurity removal through selective ion exchange mechanisms.
Solution Approach 2:
The invention introduces ion exchange resins as intermediary substances that mediate the purification process. The cation exchange resin captures metal cations, and the anion exchange resin captures silicate anions and other impurities, replacing the need for corrosive chemicals while achieving the same purification objective.
2Manufacturing precision
If conventional purification methods with multiple steps are used, then metal impurities are effectively removed, but the number of purification steps increases
Solution Approach 1:
The invention merges multiple purification functions into a integrated two-stage ion exchange system. The cation exchange resin handles metal impurity removal, while the anion exchange resin handles silicate and other anionic impurities, combining what were previously separate chemical treatment steps into a unified physical-chemical process.
Solution Approach 2:
The invention extracts and removes specific impurity components (metal cations and silicate anions) through selective ion exchange, separating them from the aqueous solution without requiring multiple bulk chemical treatment steps. This targeted extraction simplifies the overall purification pathway.
3Manufacturing precision
If conventional methods using expensive silica sources are used, then high-purity colloidal silica is produced, but production cost increases
Solution Approach 1:
The invention replaces expensive silica sources with water glass (sodium silicate), which is a much cheaper raw material. The ion exchange resins serve as temporary, regenerable purification media that enable the use of this low-cost raw material to produce high-purity colloidal silica, effectively substituting expensive consumables with cheaper alternatives.
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 method effectively reduces metal impurities like Cu and Ni in the purified aqueous solution of silicic acid, providing a cost-effective and industrially viable process for producing high-purity colloidal silica with fewer steps and without using corrosive substances.
Implementation Method 1
passing an aqueous solution of alkaline silicate having a silica concentration of 0.5% by mass or more and 10% by mass or less through a column filled with a polyamine-type chelating resin
Implementation Method 2
passing the aqueous solution passed in the step (a) through a column filled with a hydrogen-type cation exchange resin
Data Source
AI summary
There is provided a method for obtaining a purified aqueous solution of silicic acid containing less metal impurities such as Cu and Ni using water glass as a raw material with less number of purification steps than that in conventional methods without using any unnecessary additives. The method for producing a purified aqueous solution of silicic acid, the method comprising the steps of: (a) passing an aqueous solution of alkaline silicate having a silica concentration of 0.5% by mass or more and 10% by mass or less through a column filled with a polyamine-, iminodiacetic acid-, or aminophosphoric acid-type chelating resin, and (b) passing the aqueous solution passed in the step (a) through a column filled with a hydrogen-type cation exchange resin.