Pre-treatment device and method for hydrochloric acid pickling wastewater of steel products

Abstract

The invention relates to a pre-treatment device and method for hydrochloric acid pickling wastewater of steel products. The device comprises a rotary solar water heater, a negative-pressure evaporation tank, a condensation tank, a gas absorption tank, an oxidation-precipitation tank and a multi-layered filtering tower, wherein the rotary solar water heater comprises a base, a water heating pipe, a water inlet pipe of the water heater, a water outlet pipe of the water heater and a water pump; the negative-pressure evaporation tank comprises a water inlet pipe of the negative-pressure evaporation tank, a water outlet pipe of the negative-pressure evaporation tank, a heat exchanger, a pressure regulation and control device and a gas outlet pipe of the negative-pressure evaporation tan; the condensation tank comprises a steam inlet, a hydrochloric acid receiving tank, a cooling liquid inlet, a cooling liquid outlet and a steam outlet; the gas absorption tank is internally provided with a hydrochloric acid gas absorbent; the oxidation-precipitation tank comprises a mixing region and a precipitation region; aeration discs are arranged at the bottom of the mixing region, and a water distribution branch pipe of the oxidation-precipitation tank is arranged above the aeration discs; the multi-layered filtering tower comprises a top cover, a water inlet pipe of the multi-layered filtering tower, a water distribution pipe of the multi-layered filtering tower, a filtering material, a filtering material supporting frame, an air inlet and a water outlet pipe of the multi-layered filtering tower.

Description

technical field [0001] The invention relates to the technical field of wastewater treatment, in particular to a pretreatment device and method for steel hydrochloric acid pickling wastewater. Background technique [0002] Steel pickling means that before surface treatment such as galvanizing, the strip steel should have a clean and active surface to ensure the surface quality of the produced steel. In order to obtain such a surface, it is necessary to pickle the steel surface to Remove impurities such as iron oxide scale on the surface. During the pickling process, the acid cleaning agent contacts and reacts with the metal surface. With the decrease of the concentration of hydrogen ions and the increase of the concentration of metal ions in the acid solution, the pickling efficiency of the acid solution is also continuously reduced, and it becomes necessary to discharge of pickling waste. For ordinary steel, the pickling effect of hydrochloric acid is more significant than...

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Problems solved by technology

The process includes neutralization, flocculation, sedimentation, filtration and other processes. The treatment effect is average, and a large amount of alkali and flocculant are needed. There are problems such as lengthy process, unstable effluent quality, large floor area, etc., and a large amount of sludge is dehydrated. Difficult, so it is gradually eliminated in the process of practical application

Large-scale enterprises generally adopt high-temperature roasting method, which has the advantage of high recovery rate of regenerated acid and iron salt, but the investment is huge, the equipment requirements are high, the operating conditions are strict, and the operation and maintenance costs are also high, which has an impact on the large-scale promotion of the process restricted by

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