A kind of method for producing sulfuric acid from gypsum

Abstract

The invention discloses a method for producing sulfuric acid by using gypsum. The method comprises the following steps of: (1) putting gypsum powder into a roasting device, heating the temperature to a range between 700 and 850 DEG C, and continually introducing methane gas into the roasting device to react with the gypsum, wherein the molar ratio of the methane gas to the gypsum is 1: (4-4.2); and (2) sequentially introducing the mixed gas of generated sulfur dioxide, carbon dioxide and water vapor into a dust remover and a drying pipeline, then introducing the mixed gas to a condensation pipe of less than 10 DEG C below zero, introducing the rest mixed gas into a sodium hydroxide solution of which the concentration is more than or equal to 50 weight percent, newly introducing the mixed gas into the roasting device, introducing the sulfur dioxide liquefied through the condensation pipe into an oxidation chamber containing a vanadium pentoxide catalyst to convert the sulfur dioxide into sulfur trioxide at the temperature between 500 and 900 DEG C, finally introducing the generated sulfur trioxide into concentrated sulfuric acid of which the concentration is more than or equal to 75 percent, and thus obtaining the sulfuric acid. The roasting temperature in the method is lower than that in other methods for preparing the sulfuric acid by using calcium sulfate, and the method is low in energy consumption and can reduce the production cost.

Description

technical field [0001] The invention relates to a method for producing sulfuric acid, in particular to a method for producing sulfuric acid from gypsum. Background technique [0002] my country is a country lacking in sulfur resources, and the annual consumption of sulfuric acid is quite large. At the same time, the sulfur-containing waste produced in some industrial production in our country also seriously restricts the development of production. [0003] my country is rich in gypsum reserves, about 100 billion tons have been proven, plus the sulfur-containing waste residues in the production of phosphoric acid and other products, it is an astonishing data. Therefore, the production of sulfuric acid from gypsum can effectively solve the problem of lack of sulfur resources in my country. [0004] CN102838153A disclosed a method for producing sulfuric acid and calcium oxide by decomposing gypsum on December 26, 2012. The method uses gypsum and coke as raw materials, and pre...

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Problems solved by technology

The disadvantages are: (1) The raw material gypsum and coke are both solid, the solid-solid reaction rate is relatively slow, and the conversion rate of gypsum is relatively low; (2) The calcination decomposition temperature is relatively high, specifically 900-1250°C , high energy consumption and high production cost; (3) In order to avoid the occurrence of side reactions, it is necessary to control the weak oxidizing atmosphere in the furnace, which is troublesome to operate

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