Ammonium Sulfate Production via pH-Controlled Amine Separation
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Solution Overview
Problem
Existing methods for manufacturing ammonium sulfate from waste sulfuric acid containing organic tertiary amines result in low yields of recovered amines and high organic compound content in the final product, requiring additional purification steps to meet fertilizer standards.
Innovation Solution
A method involving the reaction of ammonia with waste sulfuric acid, where the pH is controlled during separation to maintain a pH of 9.5 or higher, allowing for efficient separation and reduction of organic tertiary amines, followed by optional water and volatile component reduction to achieve a total organic carbon content of less than 1% in the ammonium sulfate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the prior art process (DE 35 45 196 A1) is used to recover tertiary amines from waste sulfuric acid, then the process is simple, but the yield of recovered tertiary amines is too low and the total amount of organic compounds in the ammonium sulfate is too high
Solution Approach 1:
The patent changes the pH parameter during the separation process to optimize both amine recovery and organic compound removal. By controlling pH at specific ranges (pH 2-4 during separation, then pH 7-9 for ammonium sulfate formation), the process achieves high amine yield while producing low-TOC ammonium sulfate suitable for fertilizer use
Solution Approach 2:
The patent implements a continuous multi-stage process where waste sulfuric acid is continuously treated through sequential steps: initial separation at controlled pH, filtration, neutralization with ammonia, and final concentration. This continuous operation maintains high efficiency throughout the process, maximizing amine recovery while ensuring low organic content in the final product
2Manufacturing precision
If additional purification steps are added to reduce organic compounds in ammonium sulfate, then the total organic carbon content decreases, but the process complexity and cost increase
Solution Approach 1:
The patent performs preliminary separation of organic compounds during the main processing sequence rather than as a separate post-treatment step. The controlled pH separation and filtration steps are integrated into the ammonium sulfate production process itself, removing organic compounds before final product formation. This eliminates the need for additional dedicated purification steps while achieving TOC < 1%
Solution Approach 2:
The patent makes the separation process multi-functional: the same pH-controlled separation step simultaneously recovers valuable tertiary amines and removes organic impurities from the ammonium sulfate stream. The filtration step serves both to remove precipitated salts and to capture organic compounds. This multi-functionality reduces the number of dedicated purification steps needed
3Productivity
If the separation process is optimized to increase amine recovery, then the yield of tertiary amines increases, but the total organic carbon content in ammonium sulfate may increase
Solution Approach 1:
The patent segments the separation process into distinct stages with different pH conditions: first stage at pH 2-4 for amine separation, second stage at pH 7-9 for ammonium sulfate formation. Each stage is optimized for its specific function, allowing high amine recovery in the first stage while ensuring low organic content in the second stage. This segmentation resolves the contradiction by treating the two objectives at different process points
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 significantly increases the yield of recovered tertiary amines and reduces the total organic carbon content in ammonium sulfate to acceptable levels, eliminating the need for further purification and producing a high-purity fertilizer.
Implementation Method 1
reacting i) waste sulfuric acid comprising an organic tertiary amine with ii) ammonia in an amount sufficient to obtain a pH of 9.5 or higher
Implementation Method 2
separating the organic tertiary amine from the reaction mixture obtained in step a) wherein during the separation the pH of the reaction mixture is maintained at a pH higher than 10
Implementation Method 3
c) optionally reducing the content of water and/or other volatile components from the aqueous solution comprising the ammonium sulfate
Data Source
Figure 1
AI summary
The present invention describes a method manufacture of an ammonium sulfate composition having a total organic carbon (TOC) content of 1% by weight or less than 1 % by weight, based on the total weight of the composition, comprising the following steps: a) reacting i) waste sulfuric acid comprising an organic tertiary amines with ii) ammonia in an amount sufficient to obtain a pH of 9.5 or higher b) separating the organic tertiary amine from the reaction mixture obtained in step a) wherein during the separation the pH of the reaction mixture is maintained at a pH higher than 10 and c) optionally reducing the content of water and/or other volatile components from the aqueous solution comprising the ammonium sulfate.