Method and system for recovering waste acid produced from chlorohydric acid pickling of steel

A technology for pickling waste acid and recycling and processing, which is applied in the field of recycling and processing waste acid from hydrochloric acid pickling of steel, and can solve the problems of high energy consumption and high evaporation temperature

Active Publication Date: 2014-05-28
TIANJIN JIANCHANG ENVIRONMENTAL PROTECTION
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

It can be seen from the above that in order to obtain hydrochloric acid vapor, the evaporation and concentration of B), C) and D) must be carried out, and the evaporation temperature of these three steps is quite high, which will inevitably consume a lot of energy

Method used

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  • Method and system for recovering waste acid produced from chlorohydric acid pickling of steel

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Experimental program
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Effect test

Embodiment 1

[0035] A method for recycling waste acid from hydrochloric acid pickling of steel materials, comprising the following steps:

[0036] Step 101: Pretreating the waste acid from hydrochloric acid pickling to obtain pretreated waste acid.

[0037] Step 102: adding magnesia to the pretreated waste acid for reaction to obtain magnesite cement; wherein, adding 300-500 kg of magnesia per 1000 L of pretreated waste acid.

[0038] Among them, the pretreatment in step 101 is usually conventional treatment such as filtration and decontamination, so as to improve the product recovery rate. In order to increase the reaction rate and efficiency, stirring may also be performed during the reaction in step 102.

[0039] The principle of the above recovery and treatment method is: magnesium oxide reacts with the main components in the waste acid of steel hydrochloric acid pickling - free acid, ferrous chloride and water, and finally produces magnesite cement with industrial value (ie Mg 2 OCL...

Embodiment 2

[0051] A kind of recovery processing method of steel material hydrochloric acid pickling waste acid, such as figure 1 shown, including the following steps:

[0052] Step 201: Pretreat the waste acid from hydrochloric acid pickling to obtain pretreated waste acid.

[0053] Step 202: adding magnesium oxide to the pretreated waste acid until the pH value of the pretreated waste acid is 3.0-4.0 to obtain a first waste liquid.

[0054] Step 203: Filter the first waste liquid to obtain ferrous hydroxide and the second waste liquid.

[0055] Step 204: Add the remaining amount of magnesium oxide to the second waste liquid to obtain magnesite cement.

[0056] This embodiment is improved on the basis of Embodiment 1. Magnesium oxide is added in two times to recover more types of products. Wherein, the total amount of magnesium oxide added in step 202 and step 204 is: 300-500 kg of magnesium oxide is added for every 1000 L of pretreated waste acid. In addition, Fe(OH) is obtained in ...

Embodiment 3

[0061] A kind of recovery treatment method of steel product hydrochloric acid pickling waste acid, take processing 1000L waste acid as example, comprises the following steps:

[0062] Step 301: Pretreat the waste acid from hydrochloric acid pickling to obtain pretreated waste acid.

[0063] Step 302: Add 200kg of magnesium oxide to the pretreated waste acid to obtain the first waste liquid.

[0064] Step 303: Filter the first waste liquid to obtain ferrous hydroxide and the second waste liquid.

[0065] Step 304: Add 100kg of magnesium oxide to the second waste liquid to obtain magnesite cement.

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Abstract

The invention relates to the treatment field of waste acid produced from acid pickling of steel, in particular to a method and a system for recovering waste acid produced from chlorohydric acid pickling of steel. The method comprises steps as follows: A, waste acid produced from chlorohydric acid pickling of the steel is pretreated, and pretreated waste acid is obtained; and B, magnesium oxide is added into the pretreated waste acid for reaction, magnesite cement is obtained, and 300-500 kg of magnesium oxide is added into each 1,000 L of the pretreated waste acid. According to the recovering method and system, the waste acid produced from acid pickling is sufficiently utilized, high-temperature heating is not required, and energy consumption during recycling is reduced greatly.

Description

technical field [0001] The invention relates to the field of processing waste acid from pickling of steel materials, in particular to a method and system for recycling waste acid from hydrochloric acid pickling of steel materials. Background technique [0002] In the steel manufacturing industry, the surface of the steel is usually pickled with hydrochloric acid to remove the oxide scale on the surface, so that the steel has a clean and active surface for further processing. After pickling steel with hydrochloric acid, a large amount of pickling waste acid will be produced. If these pickling waste acids are directly discharged, it will not only seriously pollute the environment, but also cause a great waste of resources. [0003] In recent years, the method of regeneration of hydrochloric acid by evaporation method has been widely used at home and abroad to treat waste acid. These metal salts always remain in the acid solution, and the secondary steam hardly contains ferro...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23G1/36
Inventor 侯景树
Owner TIANJIN JIANCHANG ENVIRONMENTAL PROTECTION
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