Method for recycling waste liquid generated by absorbing HCl and application of method

Abstract

The invention discloses a method for recycling waste liquid generated by absorbing HCl and an application of the method. The recycling method of the waste liquid generated by absorbing HCl comprises the following steps: (1) adding excessive ammonia water, HF, H2SiF6 and NH3.H2O into the waste liquid generated by quartz etching treatment, and reacting to generate NH4F and SiO2; and (2) filtering the reaction product obtained in the step (1) to obtain a filtrate, mixing the filtrate with a waste liquid generated by absorbing HCl, and reacting NH4F with NaCl to generate NaF and NH4Cl. The invention discloses the method for recycling waste liquid generated by absorbing HCl. The waste alkali liquor, waste acid liquor, cleaning wastewater and diluted hydrochloric acid which are low in utilization value are comprehensively treated and recycled, a solution generated in the whole treatment process basically does not need to be discharged outwards, required chemicals can be circularly prepared,additional auxiliary chemicals do not need to be added, and byproducts with market utilization value can be generated.

Description

technical field [0001] The invention relates to a method for reusing waste liquid produced by absorbing HCl and its application. Background technique [0002] In the manufacturing process of optical fiber preform and high-purity quartz, it is more common to use silicon tetrachloride vapor deposition process, SiCl 4 The raw material undergoes high-temperature hydrolysis as shown in the following reaction formula 1 under the hydrogen-oxygen flame, producing SiO-containing 2 Waste gas of fine powder and HCl and SiO 2 vitreous body. Due to the limitation of deposition efficiency, the undeposited SiO 2 Fine powder can be removed and collected by bag filter; HCl in exhaust gas is absorbed by water to generate hydrochloric acid solution. Deposited SiO 2 Vitreous quartz products are formed, but the deposition rate is low, and the concentration of HCl in the exhaust gas is low, generally ≤1000mg / m 3 . Therefore, the partial pressure of HCl in the waste gas is low, and the equi...

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Problems solved by technology

[0010] It can be seen from the above that the treatment cost of dilute hydrochloric acid and waste lye produced by absorbing HCl is very high, and cannot be effectively utilized, and even further treatment is required in order to meet the emission standards; during the neutralization treatment of fluorine-containing waste acid and cleaning wastewater However, more auxiliary materials need to be consumed, and the amount of sludge produced is larger, which not only increases the cost of the enterprise, but also causes serious pollution to the environment.

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