Method for defluoridation in acid preparation by brasses

Abstract

The invention discloses a method for defluoridation in acid preparation by brasses, which comprises the following steps: (1) adding Na2SO3 as a fluorine fixing agent in solution; (2) performing the proportion of adding quantity of sodium silicate and fluorine content in the solution according to 1.1 kg / kgF of the sodium silicate; (3) obtaining the required quantity of the sodium silicate by calculation, preparing 5 percent aqueous solution with the sodium silicate, adding the sodium silicate solution into a cooling recycle acid, wherein the adding point of the sodium silicate solution is positioned in the last grade of a washing device, the temperature is 20 DEG C, the cooling recycle acid containing 5 percent sodium silicate solution is sprayed from a cooling tower, the gas goes from bottom to top, and the cooling tower is required to be over 6m. The method has simple operation without adding other devices, high defluoridation efficiency, can reduce fluorin of an HF form in dilute acid to be less than 0.1 g / L executed according to the steps, thereby making the residue quantity of the fluorin in the gas reduced to the standard requirement which is less than 2 mg / Nm and ensuring the safety operation of a post system.

Description

technical field [0001] The invention relates to a method for removing fluoride in the field of chemical industry, in particular to a method for removing fluoride in pyrite acid production Background technique [0002] During the production process of pyrite acid production, the pyrite entering the roaster contains arsenic, selenium, fluorine and other elemental compounds. After roasting, the compounds of these elements are taken out of the roaster with the furnace gas. After other conditions change, chemical changes will occur, and the products will have serious effects such as blockage and corrosion. For example, arsenic and selenium will react with the active components of the conversion catalyst to reduce the activity of the catalyst. Condensation will occur during the downstream cooling process to block the equipment pipeline, and fluorine will react with the siliceous filler of the absorption tower and the siliceous carrier of the conversion catalyst, resulting in pulve...

AI Technical Summary

Problems solved by technology

HF is easy to react with siliceous materials and transform into fluorosilicic acid and a small amount of fluorosilicate, so as to achieve the purpose of reducing fluoride. The disadvantage of this method is that the reaction speed and contact area are limited, resulting in low fluoride removal efficiency and cannot meet the process indicators. requirements, will inevitably bring additional corrosion of post-system equipment