A method for preparing iron oxide black and calcium chloride by using waste acid from iron and steel plant

An iron oxide black, iron and steel plant technology, applied in the direction of iron oxide/iron hydroxide, ferrous oxide, calcium/strontium/barium chloride, etc., can solve the problem of harsh reaction conditions of iron oxide, and achieve heavy metal Low content, mild reaction conditions, and the effect of reducing displacement

Active Publication Date: 2019-10-18
杭州金丰环保科技有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The purpose of the present invention is to provide a method for preparing iron oxide black and calcium chloride using waste acid from iron and steel plants, which solves the problem of harsh reaction conditions for the preparation of iron oxide from the recovery of waste acid from iron and steel production, and has the advantages of mild reaction and easy Advantages of mass production

Method used

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  • A method for preparing iron oxide black and calcium chloride by using waste acid from iron and steel plant
  • A method for preparing iron oxide black and calcium chloride by using waste acid from iron and steel plant

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Embodiment 1

[0024] Embodiment 1: A method for preparing iron oxide black and calcium chloride by using waste acid from iron and steel plants, comprising the following steps: S1: adding clean iron sheets to the waste acid from iron and steel plants to fully react with hydrochloric acid to make excess iron sheets, and then adding The coagulant aid improves the sedimentation speed, and the coagulant aid is allowed to stand for clarification. The concentration of the coagulant aid added is 8ppm; in the present embodiment, the coagulant aid adopts polyacrylamide;

[0025] S2: Take 14m 3 The supernatant was added to 50m 3 In the reactor, add 16m 3 Calcium hydroxide suspension with a mass fraction of 15 wt%, adjust the pH value to 6-9, and heat up to 95°C;

[0026] S3: Oxidation by blasting air, the air velocity is 6m 3 / min, when the pH is read from the pH meter and is less than 6.5 during the oxidation process, immediately add a calcium hydroxide suspension with a mass fraction of 15wt%, an...

Embodiment 2

[0029]Embodiment 2: a kind of method adopting iron and steel plant waste acid to prepare iron oxide black and calcium chloride comprises the steps:

[0030] S1: Add clean iron sheet to the waste acid of the iron and steel plant and fully react with hydrochloric acid to make the iron sheet excessive. After the reaction, add a coagulant to increase the precipitation speed, and let it stand for clarification. The concentration of the coagulant is 5ppm; in this embodiment, Polyacrylamide is used as coagulant aid;

[0031] S2: take 12m 3 The supernatant was added to 50m 3 Reactor, add 14m 3 Calcium hydroxide suspension with a mass fraction of 15 wt%, adjust the pH value to 6-9, and heat up to 95°C;

[0032] S3: Oxidation by blasting air, the air velocity is 6m 3 / min, when the pH is read from the pH meter and is less than 6.5 during the oxidation process, immediately add a calcium hydroxide suspension with a mass fraction of 15wt%, and the amount added each time is 0.5m 3 ; Ke...

Embodiment 3

[0035] Embodiment 3: a kind of method adopting iron and steel plant waste acid to prepare iron oxide black and calcium chloride comprises the steps:

[0036] S1: Add clean iron sheet to the waste acid of iron and steel plant and fully react with hydrochloric acid to make the iron sheet excessive. After the reaction, add a coagulant to increase the precipitation speed, and let it stand for clarification. The concentration of the coagulant is 10ppm; in this embodiment, The coagulant is sodium carboxymethyl cellulose;

[0037] S2: take 13m 3 The supernatant was added to 50m 3 Reactor, add 14m 3 The mass fraction is 15wt% calcium hydroxide suspension, the pH value is adjusted to 6-9, and the temperature is raised to 90°C;

[0038] S3: Oxidation by blasting air, the air velocity is 6m 3 / min, when the pH is read from the pH meter and is less than 6.5 during the oxidation process, immediately add a calcium hydroxide suspension with a mass fraction of 15wt%, and the amount added ...

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Abstract

The invention discloses a method for preparing black iron oxide and calcium chloride by adopting waste acid of a steel plant. The method comprises the following steps: S1) adding iron sheet into the waste acid of the steel plant for fully reacting, adding excessive iron sheet, standing by and clarifying after reaction; S2) taking supernate, adding calcium hydroxide, regulating pH value to 6-9 and rising temperature to 80-95 DEG C; S3) blowing in air and oxidizing, and meanwhile, supplementing calcium hydroxide for keeping pH value within 6-9, keeping the temperature at 80-95 DEG C till showing the required color through reaction, keeping the temperature for 30-60min and discharging; S4) acquiring filter residue and filtrate after solid-liquid separation, adding hydrochloric acid into the filter residue for removing calcium, and then performing rinsing, filter pressing, drying and grinding, thereby acquiring the black iron oxide; and S5) adding heavy-removing agent into the filtrate for removing heavy metal ions, removing impurities, concentrating clear liquid, preparing a calcium chloride solution, continuously crystallizing and drying, thereby acquiring the calcium chloride solid. The method disclosed by the invention is capable of solving the problem of harsh reaction condition for preparing ferric oxide by recycling the waste acid generated from steel at present and has the advantages of mild reaction and easiness in volume production.

Description

technical field [0001] The invention relates to the technical field of iron oxide preparation, in particular to a method for preparing iron oxide black and calcium chloride by using waste acid from iron and steel plants. Background technique [0002] In order to remove the oxide scale on the surface of the steel plate in the process of steel production, the iron and steel plant all use the pickling process. At present, most of them use hydrochloric acid as the medium for pickling the steel plate. The iron oxide scale on the surface of the plate is treated with hydrochloric acid to form FeCl 2 and FeCl 3 , and dissolved in hydrochloric acid solution, the amount of waste acid solution is large, Fe 2+ , Fe 3+ and Cl - High ion concentration. At present, nearly one million cubic meters of this kind of waste liquid is discharged every year in the country. With the improvement of steel production and quality, the discharge of pickling waste liquid will continue to increase. I...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01G49/08C01F11/28
Inventor 周益钧
Owner 杭州金丰环保科技有限公司
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