Hexafluorosilicic Acid Processing via Two-Stage Neutralization
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Solution Overview
Problem
The existing method for producing hydrogen fluoride from hexafluorosilicic acid is energy-intensive due to the high energy consumption required for evaporating water from dilute ammonium fluoride solutions during the production process.
Innovation Solution
A two-stage alkaline neutralization process is employed to form a poorly soluble hexafluorosilicate, which is then crystallized and separated by filtration, followed by combustion of the solid hexafluorosilicate with an oxygen-containing oxidant to produce hydrogen fluoride, reducing the need for energy-intensive evaporation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If water is evaporated from dilute ammonium fluoride solution to produce hydrogen fluoride, then hydrogen fluoride can be obtained, but energy consumption increases significantly
Solution Approach 1:
The patent applies preliminary action by neutralizing hexafluorosilicic acid with ammonia to form ammonium fluoride precipitate before the evaporation stage. This preliminary chemical transformation concentrates the fluoride content and reduces the volume of water that needs to be evaporated, thereby reducing energy consumption while maintaining hydrogen fluoride production efficiency
Solution Approach 2:
The patent changes the chemical parameters by transforming hexafluorosilicic acid into ammonium fluoride through neutralization, then further transforming it into hydrogen fluoride through combustion. This parameter change in chemical composition allows for reduced water content and lower energy consumption during the evaporation and processing stages
2Quantity of substance
If aqueous solution of hexafluorosilicic acid is neutralized with ammonia to form ammonium fluoride, then hydrogen fluoride can be produced, but water content increases requiring energy-consuming evaporation
Solution Approach 1:
The patent extracts water from the system by forming a precipitate of ammonium fluoride through neutralization, then separating it from the aqueous solution. This extraction of water through precipitation and filtration reduces the volume of water that would otherwise need to be evaporated, thereby reducing energy loss
Solution Approach 2:
The patent utilizes phase transitions by transforming the aqueous solution into a solid precipitate through neutralization, then converting it back to a gaseous state during combustion to produce hydrogen fluoride. This phase transition sequence allows for water removal and energy-efficient processing
3Quantity of substance
If dilute ammonium fluoride solution is evaporated to concentrate fluoride, then hydrogen fluoride can be obtained, but process duration increases
Solution Approach 1:
The patent applies preliminary action by pre-concentrating the fluoride content through neutralization and precipitation before the evaporation stage. This preliminary concentration reduces the time required for subsequent evaporation and processing, thereby shortening the overall process duration while achieving the desired fluoride concentration
Solution Approach 2:
The patent maintains continuity of useful action by implementing a continuous neutralization and precipitation process that directly feeds into the combustion stage. This continuous operation eliminates idle time and intermediate steps, reducing process duration while maintaining efficient fluoride concentration
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 reduces energy consumption by eliminating the need for evaporating water, achieving a two-fold decrease in energy costs and process duration.
Implementation Method 1
neutralizing an aqueous solution of HSA with an alkaline agent to produce ammonium fluoride
Implementation Method 2
form a poorly soluble hexafluorosilicate, which is then crystallized and separated by filtration
Implementation Method 3
solid hexafluorosilicate is treated with an ammonia-containing agent to produce an aqueous solution of ammonium fluoride
Implementation Method 4
the aqueous ammonium fluoride solution is burned in an oxygen-containing oxidant. HF and water are condensed from the combustion products
Implementation Method 5
HF and water are condensed from the combustion products, and the HF is extracted
Implementation Method 6
Its solid products are filtered, then the aqueous ammonium fluoride solution is burned
Data Source
AI summary
The method includes neutralizing an aqueous solution of HSA with an alkaline agent to produce ammonium fluoride and subsequently combusting it in a fire of an oxygen-containing oxidant and a hydrogen-containing fuel. It is characterized by the alkaline neutralization, which occurs in two stages. In the first stage, the aqueous hexafluorosilicic acid solution is neutralized with an alkaline agent to obtain a suspension of the correspondent hexafluorosilicate in water, after which the water is removed from the suspension. In the second stage, solid hexafluorosilicate is treated with an ammonia-containing agent to produce an aqueous solution of ammonium fluoride. Its solid products are filtered, then the aqueous ammonium fluoride solution is burned in an oxygen-containing oxidant. Hydrogen fluoride and water are condensed from the combustion products, and then the hydrogen fluoride is extracted.