Production method of electronic grade sulfuric acid

Abstract

The invention discloses a production method of electronic-grade sulfuric acid, which belongs to the technical field of electronic chemical production. The production method includes normal temperature absorption conversion, negative pressure low-temperature evaporation, low temperature absorption and temperature-increasing degassing steps, wherein the normal temperature absorption conversion is to absorb the sulfur trioxide in the furnace gas through concentrated sulfuric acid to obtain fuming sulfuric acid, and then use the fuming sulfuric acid Oxidative transformation of hydrogen peroxide aqueous solution; wherein the negative pressure low-temperature evaporation is to use an evaporation purification device to evaporate sulfur trioxide gas without boiling the liquid under the condition of low-temperature hot water below 50 ° C as the heating medium; Low-temperature absorption is absorption with ultra-pure water or ultra-pure sulfuric acid at low temperature; temperature-increasing degassing is the process of removing gas in a liquid at a temperature slightly higher than normal temperature. The production method can ensure the safety of operation while obtaining high-quality electronic-grade sulfuric acid and ensuring the output and efficiency.

Description

technical field [0001] The invention relates to a production method of sulfuric acid, in particular to a production method of electronic-grade sulfuric acid, and belongs to the technical field of electronic chemical production. Background technique [0002] Electronic grade sulfuric acid, also known as ultra-pure sulfuric acid, is an ultra-clean and high-purity reagent, and is the most widely used wet electronic chemical in industry. It is mainly used for cleaning, photolithography, corrosion, etc. of silicon wafers, as well as corrosion and cleaning of printed circuit boards, etc. , can effectively remove particulate impurities, inorganic residues and carbon deposits on wafers and printed circuit boards. [0003] The preparation process of electronic grade sulfuric acid mainly includes rectification method and gas absorption method. The rectification method is a distillation method that uses reflux to obtain high-purity separation of the liquid mixture. Specifically, the i...

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Problems solved by technology

[0005] In the preparation process of the above-mentioned prior art, steam is used for distillation and purification in the distillation purification stage, and the absorption stage is normal temperature absorption, and the operating temperature is relatively high, so the safety is low; at the same time, the degassing stage in the prior art also uses normal temperature Degassing method, the gas contained in the liquid is difficult to remove effectively

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