Method for preparing nanoscale ferroferric oxide from steel pickling wastewater

A ferroferric oxide and steel pickling technology, which is applied to the oxides of sub-ferric iron, chemical instruments and methods, iron oxide/iron hydroxide, etc., can solve problems such as scabbing, waste of resources, and complicated process flow. Achieve the effect of reducing concentration and avoiding corrosion

Active Publication Date: 2015-09-02
TIANJIN UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Its biggest disadvantage is that the generated sediment occupies a large area and the transportation cost is high; secondly, the secondary pollution is serious, and there is basically no product recovery, resulting in a great waste of resources
Others, such as evaporation concentration and high-temperature roasting, can recover hydrochloric acid and iron salts in pickling wastewater, but because they all need to be carried out at a high temperature of about 600°C in a hydrochloric acid atmosphere, they have the following fatal disadvantages: complex process , equipment investment is large, energy consumption is high; hydrochloric acid corrosion resistant materials are difficult to solve at high temperature; problems such as blockage and scarring of equipment pipelines in the recycling process

Method used

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  • Method for preparing nanoscale ferroferric oxide from steel pickling wastewater

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Experimental program
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Effect test

Embodiment 1

[0025] The method for preparing nano-scale ferroferric oxide by iron and steel pickling wastewater consists of the following steps:

[0026] (1) Filter the steel pickling wastewater to remove suspended solids in the wastewater, and heat to 30°C;

[0027] (2) Add hydrogen peroxide to oxidize part of the ferrous ions in the waste water to ferric ions, and control the molar ratio of ferrous ions to ferric ions to be 1:1.7, stop adding hydrogen peroxide;

[0028] (3) add sodium citrate, control the concentration of sodium citrate in the waste water to be 1g / L;

[0029] (4) Add sodium hydroxide, after the pH value of waste water is adjusted to 10, stop adding sodium hydroxide; Add sodium metasilicate afterwards, the addition of sodium metasilicate is 2g / L;

[0030] (5) Continue heating the solution obtained in step (4) to 60° C., keep it warm for 1 hour, and then cool it naturally to room temperature;

[0031] (6) After solid-liquid separation, the obtained solid powder is washed...

Embodiment 2

[0033] The method for preparing nano-scale ferroferric oxide by iron and steel pickling wastewater consists of the following steps:

[0034] (1) Filtrate the steel pickling wastewater to remove suspended matter in the wastewater, and heat it to 40°C;

[0035] (2) Add hydrogen peroxide to oxidize part of the ferrous ions in the waste water into ferric ions, and control the molar ratio of ferrous ions to ferric ions to be 1:1.8, stop adding hydrogen peroxide;

[0036] (3) add sodium citrate, control the concentration of sodium citrate in the waste water to be 3g / L;

[0037] (4) Add sodium hydroxide, after the pH value of waste water is adjusted to 11, stop adding sodium hydroxide; Add sodium metasilicate afterwards, the addition of sodium metasilicate is 3g / L;

[0038] (5) Continue heating the solution obtained in step (4) to 70° C., keep it warm for 2 hours, and then cool it naturally to room temperature;

[0039] (6) After solid-liquid separation, the obtained solid powder i...

Embodiment 3

[0041] The method for preparing nano-scale ferroferric oxide by iron and steel pickling wastewater consists of the following steps:

[0042] (1) Filtrate the steel pickling wastewater to remove suspended solids in the wastewater, and heat to 50°C;

[0043] (2) Add hydrogen peroxide to oxidize part of the ferrous ions in the waste water into ferric ions, and control the molar ratio of ferrous ions to ferric ions to be 1:1.9, stop adding hydrogen peroxide;

[0044] (3) add sodium citrate, control the concentration of sodium citrate in the waste water to be 5g / L;

[0045] (4) Add sodium hydroxide, after the pH value of waste water is adjusted to 12, stop adding sodium hydroxide; Add sodium metasilicate afterwards, the addition of sodium metasilicate is 4g / L;

[0046] (5) Continue heating the solution obtained in step (4) to 80° C., keep it warm for 3 hours, and then cool it naturally to room temperature;

[0047] (6) After solid-liquid separation, the obtained solid powder is w...

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Abstract

The invention relates to a method for preparing nanoscale ferroferric oxide from steel pickling wastewater. The method comprises the following steps: filtering steel pickling wastewater to remove suspended solids out of wastewater; oxidizing partial divalent iron ions in wastewater into trivalent iron ions, controlling the molar ratio of divalent iron ions to trivalent iron ions to be (1: 1.7)-(1:1.9), and stopping adding an oxidant; controlling the concentration of an aid in wastewater at 1g/L-5g/L; adding a pH regulator to regulate the pH value of wastewater to be 10-12; adding 2g/L-4g/L of sodium metasilicate; further heating the obtained solution to 60-80 DEG C, maintaining the temperature for 1-3 hours, and naturally cooling to the room temperature; after carrying out solid-liquid separation, washing and drying obtained solid powder, so as to obtain nanoscale ferroferric oxide. According to the method, steel pickling wastewater can be subjected to effective resourceful treatment, and nanoscale ferroferric can be prepared by virtue of divalent iron ions contained in wastewater.

Description

technical field [0001] The invention belongs to the technical field of waste water treatment, and in particular relates to a method for preparing nanometer ferroferric oxide by using steel pickling waste water. Background technique [0002] Before steel is processed, it usually needs to be pickled with a large amount of hydrochloric acid to remove the oxide scale on the surface. Along with the pickling, a large amount of pickling waste water containing hydrochloric acid and ferrous ions is produced. For example, the pickling wastewater discharged by a medium-sized rolling mill is as many as tens of tons or even hundreds of tons every day. Its typical composition is 5-15% hydrochloric acid and 80-150g / L ferrous ion content. Because pickling wastewater has huge hidden dangers to environmental pollution and ecological safety, it is regarded as one of the hazardous wastes in my country and included in the "National Hazardous Waste List". [0003] For the treatment of iron and ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F9/04C01G49/08B82Y30/00
Inventor 刘涉江王存贵杨宏扬
Owner TIANJIN UNIV
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