Energy-saving acid pickling method and acid pickling system

Abstract

The invention provides an energy-saving acid pickling method and an acid pickling system. The acid pickling system comprises an acid pickling tank, a micro filter, a water tank and the like. The acidpickling method comprises the following steps of (1) arranging a nozzle system in the acid pickling tank, and discharging iron powder and an acid liquor out of a tank body under the action of a nozzle; (2) after discharging the acid liquor mixed with metal powder out of the tank body, filtering and intercepting most metal powder through the micro filter; and (3) after finishing acid pickling operation and evacuating waste acid of the acid pickling tank, closing an acid liquor valve, opening a cleaning valve, using clean water for omni-directionally circularly cleaning in the acid tank withoutdead corners through the nozzle system, returning formed acid water into the water tank, then adding sodium hydroxide for regulating PH to be neutral, and continuously returning to a line for cleaning. According to the system, slags can be automatically discharged, the acid liquor can be automatically purified, the acid tank can be automatically cleaned, the acid consumption, the water consumptionand the labor consumption are greatly reduced, and the aims of energy conversation and consumption reduction are achieved.

Description

technical field [0001] The invention belongs to the technical field of production waste liquid treatment, and in particular relates to an energy-saving pickling method and a pickling system. Background technique [0002] With the rapid development of my country's industrial economy, it has also led to the rapid development of the steel industry. Steel components must be pickled before hot and cold rolling, electroplating, and spraying to remove surface oxides. The pickling process produces a large amount of waste acid. , waste residue, also consumes a lot of water resources, the main components in the waste acid liquid are S042-, H+, Fe2+, Na+, Cn6+, F-, Men+, Ni, etc., of which Cn6+, F-, Fe2+, Men+ are the main pollutants . [0003] The existing pickling method adopts the mode of pumping acid solution in the middle pipeline in the pickling tank to take away part of the metal powder to the sedimentation tank outside the tank body, the iron powder settles to the bottom through...

AI Technical Summary

Problems solved by technology

[0005] 1. The acid tank only brings out a small amount of metal oxide iron powder in the suction circulation mode, but there is still a large amount of deposition to the bottom of the pickling tank, which accumulates thicker and thicker, scrapes the surface of the strip steel, and affects the surface quality of the strip steel. If most of the iron powder cannot be discharged in a timely and effective manner, the acid solution will not be purified, and the continuous chemical saturation reaction between acid and iron powder will have a greater effect, weakening the continuous etching ability of the acid

[0006] 2. The discharged waste acid must be roasted and regenerated in the acid regeneration furnace to obtain clean acid, but the cost of furnace consumption is high.

The waste acid discharged into the wastewater station needs to be neutralized with chemicals. Lime is the most effective and cheapest neutralizer, but using lime as a neutralizer also produces a large amount of calcium fluoride and calcium sulfate; metal hydroxide sludge , The sludge containing heavy metals is included in the list of hazardous solid wastes. The landfill treatment of hazardous solid wastes will cause damage to groundwater and occupy a large amount of land resources. If it is returned to the furnace for incineration, the cost will be very high. The root ions will continue to etch the furnace wall, which increases the furnace consumption and reduces the service life of the furnace body

[0007] 3. After pickling in the pickling line, the waste acid needs to be cleaned and deposited in the tank. The workers open the tank cover and use high-pressure water guns to clean the tank outside the ground and personnel. The working conditions on site are relatively poor. It also wastes a lot of clean water, and the safety and environmental protection issues are more prominent

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