Process method for preparing sulfuric acid from low-sulfur-content pyrite

Abstract

The invention relates to a process method for preparing sulfuric acid from low-sulfur-content pyrite. The method comprises the steps of raw material treatment, raw material roasting, furnace gas catalytic oxidation and sulfuric acid preparation by adding water. The raw material roasting comprises a roasting furnace, a preheating device is arranged on the roasting furnace, and the preheating devicecomprises a case formed by stacking insulating bricks, a conveyor and a heating sleeve fixed in the case; an upper heating cavity extending in an S shape in the length direction of the machine box isformed in the inner top face of the heating sleeve, a lower heating cavity extending in the S shape in the length direction of the machine box is formed in the inner bottom face of the heating sleeve, and the lower heating cavity communicates with the upper heating cavity. An air outlet pipe communicated with the upper heating cavity is fixed to the machine box, an air inlet pipe communicated with the lower heating cavity is fixed to the bottom of the machine box, and high-temperature furnace gas generated in the roasting furnace is introduced into the air inlet pipe. The method has the effect of increasing the generation speed of sulfur dioxide in the fluidized bed roaster so that the concentration of prepared sulfur dioxide is increased and the purity of the prepared sulfuric acid is improved.

Description

technical field [0001] The invention relates to the technical field of sulfuric acid preparation, in particular to a process for preparing sulfuric acid from pyrite with low sulfur content. Background technique [0002] In industry, pyrite is usually used to prepare sulfuric acid. The preparation process is as follows: using pyrite as raw material, boiling and roasting the raw material in excess oxygen to produce sulfur dioxide, and then sulfur dioxide reacts under the action of a catalyst to form sulfur trioxide, and finally produces sulfuric acid. The resulting sulfur trioxide reacts with water to produce sulfuric acid. [0003] At present, the invention patent with the notification number CN1772598A discloses a new process for producing acid from pyrite, including raw material treatment and roasting process. The slag after desulfurization and roasting is reduced by a reducing agent at 550-570°C, and the iron in the pyrite slag is converted into ferroferric oxide that can...

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Problems solved by technology

[0004] In addition, the roasting of pyrite is mainly the reaction of iron disulfide in pyrite and oxygen to produce sulfur dioxide. The reaction temperature of this reaction is 600°C. When it is below 600°C, there is almost no reaction, so pyrite at normal temperature enters From the perspective of the microscopic reaction process in the fluidized roasting furnace, it is necessary for the pyrite to react with the excess oxygen in the furnace when the temperature is raised to nearly 600°C, which increases the reaction time and reduces the generation rate of sulfur dioxide. If other elements in the pyrite Reacting with oxygen will reduce the concentration of sulfur dioxide in the final furnace gas and affect the purity of sulfuric acid.

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