Stannous Oxide Production via pH-Controlled Precipitation
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Solution Overview
Problem
Existing methods for Sn plating solutions fail to effectively remove impurities such as Na, K, Pb, Fe, Ni, Zn, Al, Mg, Ca, Cr, Mn, Co, and Cd, which accumulate over time and deteriorate platability, limiting the quality of plating films.
Innovation Solution
A method involving the production of stannous oxide through a series of steps including forming a Sn ion-containing acid solution, neutralizing with alkaline solutions to create Sn precipitates, separating and dispersing them, and then forming SnO by heating, which reduces impurity content to 1 ppm or less, allowing for efficient removal of these elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods are used to remove Cu from Sn plating solution, then Cu content is reduced, but other impurities such as Na, K, Pb, Fe, Ni, Zn, Al, Mg, Ca, Cr, Mn, Co, In, and Cd remain in the solution
Solution Approach 1:
The patent changes the pH parameter from conventional ranges to specifically 3-6, which enables simultaneous precipitation of multiple impurity elements including Cu, Pb, Fe, Ni, Zn, Al, Mg, Ca, Cr, Mn, Co, In, and Cd while keeping Sn in solution. This parameter change transforms the selective removal approach into a comprehensive removal approach.
Solution Approach 2:
The patent uses a universal alkaline solution (ammonium carbonate, ammonium bicarbonate, or aqueous ammonia) that can remove multiple types of impurities simultaneously through a single neutralization process, rather than requiring separate treatment steps for each impurity element.
2Productivity
If Sn plating solution is used continuously, then plating production is maintained, but impurities accumulate and platability deteriorates over time
Solution Approach 1:
The patent enables recovery of Sn from used plating solution by precipitating impurities that carry adsorbed Sn, then treating the precipitated Sn with acid to regenerate usable Sn plating solution. This allows continuous production while maintaining plating quality through periodic regeneration.
Solution Approach 2:
The patent implements a feedback mechanism where the state of the plating solution (impurity accumulation) is monitored and the solution is regenerated when impurities reach levels that would affect plating quality, ensuring continuous high-quality production.
3Ease of manufacture
If pH is not controlled during neutralization, then the process is simpler, but impurity removal efficiency decreases
Solution Approach 1:
The patent specifies pH control at 3-6 during neutralization, which optimizes the precipitation of impurity elements while keeping Sn in solution. This controlled parameter range achieves high impurity removal efficiency without requiring complex multi-step processes.
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
The method significantly reduces impurity content in stannous oxide and Sn plating solutions, improving platability and enabling the production of high-quality plating films by effectively removing Na, K, Pb, Fe, Ni, Cu, Zn, Al, Mg, Ca, Cr, Mn, Co, and Cd, maintaining their levels at 1 ppm or less.
Implementation Method 1
a first neutralizing step, which is a step of forming Sn precipitates by adding one or more of alkaline solutions of ammonium carbonate, ammonium bicarbonate, and aqueous ammonia to the Sn ion-containing acid solution to retain pH at 3-6 therein
Implementation Method 2
a second neutralizing step, which is a step of forming SnO from the Sn precipitates by adding an alkaline solution to the dispersion liquid of the Sn precipitates and then by heating
Data Source
AI summary
The method of producing stannous oxide includes: a Sn ion-containing acid solution forming step (S01); a first neutralizing step (S02), which is a step of forming Sn precipitates by adding one or more of alkaline solutions of ammonium carbonate, ammonium bicarbonate, and aqueous ammonia to the Sn ion-containing acid solution to retain pH at 3-6 therein; a Sn precipitate separating step (S03); a Sn precipitate dispersing step (S04), which is a step of dispersing the separated Sn precipitates in a solvent liquid to obtain a dispersion liquid; and a second neutralizing step (S06), which is a step of forming SnO by adding an alkaline solution to the dispersion liquid of the Sn precipitates and then by heating, wherein Na, K, Pb, Fe, Ni, Cu, Zn, Al, Mg, Ca, Cr, Mn, Co, In, and Cd reside in the Sn ion-containing acid solution in the first neutralizing step (S02).