Wet Process for High Purity Phosphoric Acid Production
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Solution Overview
Problem
Current methods for producing electronic grade phosphoric acid are either costly due to high energy consumption in dry processes or inefficient in removing metal ions like antimony, which are difficult to remove, limiting the production of high purity phosphoric acid suitable for semiconductor and electronic device manufacturing.
Innovation Solution
A wet process involving successive steps of attacking a phosphate salt with a strong acid, separating and neutralizing to form a slurry, followed by ion-exchange to produce high purity phosphoric acid, including the use of hydrochloric acid and organic solvent extraction to remove impurities, specifically targeting the removal of antimony and other metal ions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dry methods based on thermal reduction process of phosphate rock at very high temperature are used, then electronic grade phosphoric acid is produced, but energy consumption is extremely high
Solution Approach 1:
The invention changes the temperature parameter from very high temperature (dry method) to moderate temperature (wet method), and changes the reaction medium from direct thermal reduction to aqueous solution chemistry, thereby achieving electronic grade purity with significantly reduced energy consumption
Solution Approach 2:
The invention introduces an intermediary wet chemical process using phosphoric acid and organic solvent extraction as intermediate steps between phosphate rock and final electronic grade product, avoiding direct high-temperature thermal reduction while achieving the same purification goal
2Productivity
If wet methods with concentrated HCl solution are used to attack phosphate rock, then phosphoric acid is produced, but metal ions like antimony are difficult to remove
Solution Approach 1:
The invention extracts metal ions like antimony from the phosphoric acid solution using organic solvents (e.g., MIBK, TBP) in liquid-liquid extraction steps, separating the harmful impurities from the desired product to achieve electronic grade purity
Solution Approach 2:
The invention uses disposable organic extraction phases that can be easily discarded after extracting metal ions, replacing complex high-temperature purification processes with simple liquid-liquid extraction using readily available organic solvents
3Productivity
If concentrated HCl solution (20-30% by weight) is used for attack, then phosphoric acid production is efficient, but rock quality requirements increase and grinding costs increase
Solution Approach 1:
The invention segments the purification process into multiple stages: initial wet attack with HCl, followed by sequential organic solvent extraction steps, and final purification. This breaks down the complex task of producing electronic grade acid from lower quality rock into manageable steps, each with specific function
Solution Approach 2:
The invention performs preliminary attack of phosphate rock with HCl to convert it to soluble phosphoric acid form before extraction, preparing the material in advance for efficient separation of metal ions through organic solvent extraction, thereby simplifying subsequent purification steps
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 process effectively produces high purity phosphoric acid with reduced antimony content, achieving electronic grade quality suitable for semiconductor and electronic device manufacturing, while reducing energy costs and improving purity standards.
Implementation Method 1
attack of phosphate rock with acids, principally sulphuric acid, but also nitric, perchloric or hydrochloric acids
Implementation Method 2
extracting the second phosphoric acid with an organic solvent to form an organic extraction phase containing phosphoric acid and an aqueous extraction phase containing impurities
Implementation Method 3
applying ion-exchange to the third phosphoric acid to produce a high purity phosphoric acid
Data Source
Figure 1
AI summary
The invention relates to a process for the production of high purity phosphoric acid which has a very low content in antimony, and is suitable for food, pharmaceutical, or electronic industry.