Hydrochloric Acid Purification Through Extended Gas-Liquid Contact

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Solution Overview

Problem

Existing methods for producing high-purity hydrochloric acid fail to efficiently remove low-boiling-point impurities, particularly inert gases like nitrogen and oxygen, which are inhibiting factors for semiconductor manufacturing due to their presence even after aeration treatments.

Innovation Solution

A method involving gas-liquid contact between hydrogen chloride gas and crude hydrochloric acid with a concentration below saturation, continuing the contact until an excess of 0.1% of the mass of saturated hydrochloric acid is reached to enhance impurity removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If aeration treatment with inert gas is performed to remove low-boiling-point impurities, then removal efficiency of impurities is improved, but inert gas components are newly dissolved in the hydrochloric acid

Engineering Contradiction:

Improvepurity of hydrochloric acidVSAvoiddissolved inert gas components

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent uses a liquid bridge (water layer) as an intermediary between the gas phase and hydrochloric acid liquid phase. This liquid bridge selectively absorbs impurity gases while allowing hydrogen chloride to pass through, preventing direct dissolution of inert gases into the hydrochloric acid while still achieving impurity removal

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system uses the hydrochloric acid solution itself to drive the removal process. By controlling the concentration and flow rate, the hydrochloric acid automatically creates the conditions for impurity removal through gas-liquid contact without requiring external inert gas introduction

Inventive Principle:

Principle #25Self-service

2Manufacturing precision

If distillation is performed to remove impurities, then high-boiling-point components are removed, but low-boiling-point impurities are concentrated instead

Engineering Contradiction:

Improveremoval of metallic impuritiesVSAvoidconcentration of low-boiling-point impurities

Core Design Contradiction:

Manufacturing precisionVSQuantity of substance

Solution Approach 1:

Instead of using distillation which concentrates low-boiling-point impurities, the patent inverts the approach by using gas-liquid contact where the liquid phase absorbs gases. This reverse approach allows low-boiling-point impurities to be removed while preventing their concentration

Inventive Principle:

Principle #13The other way round (Inversion)

3Quantity of substance

If gas-liquid contact is continued until saturation to maximize hydrogen chloride absorption, then hydrogen chloride concentration is improved, but low-boiling-point impurities remain in the solution

Engineering Contradiction:

Improvehydrogen chloride concentrationVSAvoidpurity of hydrochloric acid

Core Design Contradiction:

Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent applies partial action by controlling the gas-liquid contact to achieve just enough hydrogen chloride absorption without reaching complete saturation. By stopping before saturation and using controlled excess hydrogen chloride gas, the system removes impurities while maintaining optimal hydrogen chloride concentration without co-absorbing low-boiling-point impurities

Inventive Principle:

Principle #16Partial or excessive action

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 approach effectively reduces low-boiling-point impurities, including nitrogen and oxygen, to extremely low levels, enabling the production of high-purity hydrochloric acid suitable for semiconductor applications.

Implementation Method 1

bringing hydrogen chloride gas into gas-liquid contact with crude hydrochloric acid that has a hydrogen chloride concentration of less than the saturation value

Methodology Applied

Scientific EffectGas absorption: Absorption (physical)

Implementation Method 2

the crude hydrochloric acid also contains significant amounts of low-boiling-point impurities such as hydrogen, methane, ethylene, and acetylene... which are released and removed

Methodology Applied

Scientific EffectEvaporation: Evaporation

Data Source

PatentUS20250333304A1Method for producing high-purity hydrochloric acid

Publication Date: 2025.10.30 TOKUYAMA CORP

AI summary

The present invention provides a method including bringing hydrogen chloride gas into gas-liquid contact with crude hydrochloric acid that has a hydrogen chloride concentration of less than the saturation value and that contains low-boiling-point impurities, suitably at least one selected from hydrogen, nitrogen, oxygen, methane, ethylene, and acetylene, wherein the gas-liquid contact of the hydrogen chloride gas is further continued after the hydrogen chloride concentration reaches the saturation value until an excess amount of 0.1% or more of the mass of the saturated hydrochloric acid has been subjected to the contact treatment.