Production method of electronic-grade sulfuric acid

Abstract

The invention discloses a production method of electronic-grade sulfuric acid, and belongs to the technical field of electronic chemical production. The production method comprises the steps of normal-temperature absorption and conversion, negative-pressure low-temperature evaporation, low-temperature absorption and heating degassing, sulfur trioxide in furnace gas is absorbed by concentrated sulfuric acid to obtain fuming sulfuric acid through normal-temperature absorption and conversion, and then the fuming sulfuric acid is oxidized and converted by a hydrogen peroxide aqueous solution; thenegative-pressure low-temperature evaporation is to evaporate sulfur trioxide gas under the condition that liquid is not boiled by an evaporation purification device under the condition that low-temperature hot water with the temperature lower than 50 DEG C is used as a heating medium; the low-temperature absorption is that ultrapure water or ultrapure sulfuric acid is used for absorption at a lowtemperature the temperature-increasing degassing is a process of removing gas in the liquid at a temperature slightly higher than the normal temperature. According to the production method, high-quality electronic-grade sulfuric acid can be obtained, and the operation safety is ensured while the yield and the efficiency are ensured.

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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