An acid pickling accelerator for use in an acid regeneration system and a method of preparing the same

Abstract

The application discloses an acid pickling accelerator suitable for an acid regeneration system and a preparation method. The preparation raw materials include, in percentage by weight, 6-17% of a penetrating agent, 1-5% of a stripping agent, 5-10% of a dispersing agent, 1-5% of a stabilizing agent, 1-3% of a foam control agent and water supplementing to 100%. The application uses lauryl hydroxyethyl imidazoline as the penetrating agent and lauryl hydroxyl sulfobetaine as the stripping agent, accelerates the penetration of the acid liquid to the metal oxide skin, improves the sheet white degree, reduces the color difference and reduces the generation of silicon mud. After the silicon steel is pickled, the obtained regenerated acid has high purity, improves the quality of the byproduct iron oxide powder of the acid regeneration system and improves the economy of resource recovery.

Description

TECHNICAL FIELD

[0001] The present application relates to chemical method of metal material cleaning and degreasing except electrolysis, and particularly relates to an acid pickling accelerator suitable for acid regeneration system and preparation thereof. BACKGROUND

[0002] Hot-rolled silicon steel pickling is one of the main processes in silicon steel production, and the pickling can remove the surface oxides and contaminants of hot-rolled silicon steel, reduce the magnetic deterioration points, and ensure the application efficiency and stability of finished silicon steel. In addition to the common iron oxide, the oxide of silicon and silicon-iron compound are also contained in the oxide skin on the surface of silicon steel, and the solubility in conventional hydrochloric acid is very poor, which is easy to produce precipitated silicon mud, and increases the difficulty of waste acid treatment. At the same time, the high silicon content makes the oxide skin form a more dense composite structure, which hinders the penetration of acid liquid. The existing technology relies on high-concentration acid liquid or fluoride auxiliary dissolution, combined with the strict quality requirements of the surface of silicon steel, resulting in generally low pickling efficiency. The existing pickling liquid adds reducing compounds, although the pickling efficiency is improved, but the silicon mud increases, resulting in the decrease of silicon content in regenerated acid, the magnetic properties and particle size distribution of silicon-iron powder produced by regeneration are polluted by silicon, and the quality is decreased. Therefore, it is crucial to develop an acid regeneration system without reducing agent and with less silicon mud.

[0003] Chinese invention patent CN1195102C discloses a steel pickling accelerator, which uses a mixture of hydrochloric acid, sulfuric acid and hydrofluoric acid, can accelerate the removal of oxide skin generated on steel, and improves the pickling quality of steel surface, but generates more silicon mud, affecting the quality of regenerated acid. Chinese invention patent CN103526215A discloses a silicon steel pickling accelerator and a preparation method thereof, which uses corrosion inhibitor imidazoline derivative and defoaming agent tributyl phosphate, has the characteristics of convenient use, low pickling temperature, high efficiency, good "corrosion inhibition" effect, low cost and environmental friendliness, but the silicon dioxide content in the pickling liquid after pickling is high, and silicon mud is precipitated. SUMMARY

[0004] In order to improve the pickling efficiency of hot-rolled silicon steel, the existing technology generally adds reducing compounds (multivalent metal compounds, reducing agents) in the pickling accelerator, but the reducing agent reduces the Fe 3+ concentration, and the silicon dissolution ability of the acid liquid is weakened, Fe 2+The coprecipitation effect with silicate increases the silicon mud produced by pickling, increases the difficulty of waste acid treatment, and the waste acid is more likely to deposit in the pipeline, filter screen, valve, graphite heat exchanger and other parts of the acid regeneration system during the acid regeneration process, resulting in a decrease in acid regeneration efficiency and an increase in maintenance cost of the acid regeneration system; and the silicon content of the regenerated acid increases, which reduces the purity of the regenerated acid and the process stability when used in the pickling tank. At the same time, the indicators such as the magnetic performance and particle size distribution of the regenerated byproduct iron oxide powder are significantly reduced in quality due to silicon pollution. In order to develop a pickling promoter with high pickling efficiency and less silicon mud, the first aspect of the present application provides a pickling promoter suitable for an acid regeneration system, and the preparation raw materials include, in percentage by weight: 6-17% of a penetrating agent, 1-5% of a stripping agent, 5-10% of a dispersing agent, 1-5% of a stabilizing agent, 1-3% of a foam control agent, and water supplementing to 100%.

[0005] As an implementation form, the weight percentage of the penetrating agent is 13.8%.

[0006] As an implementation form, the weight percentage of the stripping agent is 2-4%.

[0007] As an implementation form, the weight percentage of the stripping agent is 3.6%.

[0008] As an implementation form, the weight percentage of the dispersing agent is 6-9%.

[0009] As an implementation form, the weight percentage of the dispersing agent is 8%.

[0010] As an implementation form, the weight percentage of the stabilizing agent is 2-4%.

[0011] As an implementation form, the weight percentage of the stabilizing agent is 3.5%.

[0012] As an implementation form, the weight percentage of the foam control agent is 2%.

[0013] As an implementation form, the penetrating agent includes at least one of lauryl hydroxyethyl imidazoline, heptadecenyl amine ethyl imidazoline quaternary ammonium salt, or disodium cocamidopropyl betaine diacetate.

[0014] As an implementation form, the penetrating agent is lauryl hydroxyethyl imidazoline.

[0015] As an implementation form, the stripping agent includes at least one of lauryl hydroxy sulfobetaine, dodecyl dimethyl betaine, or cocamide propyl betaine.

[0016] As an implementation form, the stripping agent is lauryl hydroxy sulfobetaine.

[0017] The inventors found in the experiment that the lauryl hydroxyethyl imidazoline as the penetrant and the lauryl hydroxy sulfobetaine as the stripping agent can still maintain good permeability under strong acid conditions, can effectively accelerate the penetration of the acid liquid to the metal oxide scale, and the reason may be that the lauryl hydroxyethyl imidazoline has corrosion inhibition effect on the oxide scale of silicon steel, slowly penetrates under strong acid conditions to prevent over pickling, the lauryl hydroxy sulfobetaine has cationic characteristics under acidic conditions, has adsorption effect on the metal oxide scale material with negative electricity, improves the whiteness of the plate surface in the penetration and stripping process, reduces the color difference, improves the pickling speed, reduces the dissolution of silicon ions into the acid liquid, and reduces the generation of silicon mud.

[0018] As an implementation form, the dispersant comprises at least one of polyoxyethylene sorbitan monolaurate, sodium polyacrylate or gum arabic.

[0019] As an implementation form, the dispersant is polyoxyethylene sorbitan monolaurate.

[0020] As an implementation form, the stabilizer comprises at least one of polyethylene glycol octylphenyl ether or polyoxyethylene mono-tert-octylphenyl ether.

[0021] As an implementation form, the stabilizer is polyethylene glycol octylphenyl ether.

[0022] The inventors found in the experiment that the polyoxyethylene sorbitan monolaurate as the dispersant and the polyethylene glycol octylphenyl ether as the stabilizer can reduce the content of silicon dioxide in the regenerated acid and reduce the generation of silicon mud, and the reason may be that the polyoxyethylene sorbitan monolaurate is adsorbed on the surface of silicate particles to form a steric hindrance effect, promotes uniform dispersion of silicate particles, and avoids rapid precipitation caused by too high local concentration. And the polyethylene glycol octylphenyl ether controls the formation of a double electric layer on the surface of silicate colloidal particles, enhances the stability of the colloid, prevents the colloid from being adsorbed and aggregated, and further avoids the generation of silicon mud precipitation.

[0023] As an implementation form, the weight ratio of the dispersant to the stabilizer is 8:3.5.

[0024] The inventors found in the experiment that the weight ratio of the dispersant to the stabilizer is 8:3.5, which can effectively reduce the silicon mud generated by the aggregation of silicates in the acid liquid, prevent the deposition of silicon mud on the pipelines, filter screens and other equipment in the regeneration system, and the reason may be that the dispersant is adsorbed on the surface of silicate particles to form a steric hindrance effect, a double electric layer is formed on the surface of silicate colloidal particles to enhance the stability of the colloid, and the weight ratio of the dispersant to the stabilizer is 8:3.5 to achieve the balance of physical stability and electrochemical stability, thereby further reducing the aggregation of silicates in the acid liquid.

[0025] As an implementation form, the foam control agent comprises at least one of propylene glycol block polyether, polyoxyethylene polyoxypropylene block polyether, dimethicone or carbon alcohol defoamer.

[0026] As an implementation form, the foam control agent is propylene glycol block polyether.

[0027] The inventors use propylene glycol block polyether as a foam control agent, which can prevent excessive foam overflow during pickling and avoid foam affecting acid regeneration treatment during waste acid treatment. Meanwhile, propylene glycol block polyether has cleaning and dispersing effects on oil stains, preventing the influence of oil stains on the surface of silicon steel on pickling.

[0028] The second aspect of the present application provides a preparation method of a pickling accelerator suitable for an acid regeneration system, comprising the following steps:

[0029] S1: water is added to start stirring, and a penetrating agent is added under stirring;

[0030] S2: then, a stripping agent, a dispersing agent, a stabilizing agent and a foam control agent are sequentially added, and mixed and stirred uniformly to obtain the pickling accelerator.

[0031] As an implementation form, the use method of the pickling accelerator comprises the following steps: the pickling accelerator is added to acid liquor, mixed uniformly, and silicon steel is pickled in the acid liquor with the pickling accelerator.

[0032] As an implementation form, the acid liquor comprises but is not limited to hydrochloric acid.

[0033] As an implementation form, the concentration of the acid liquor is 20%-22%.

[0034] As an implementation form, the addition concentration of the pickling accelerator is 0.2%-0.5%.

[0035] As an implementation form, the pickling speed of the silicon steel is 80-110 m / min.

[0036] As an implementation form, the pickling temperature is 80℃-85℃.

[0037] Compared with the prior art, the present application has the following beneficial effects:

[0038] (1) The pickling accelerator suitable for an acid regeneration system has lauryl hydroxyethyl imidazoline as a penetrating agent and lauryl hydroxyl sulfobetaine as a stripping agent, which accelerates the penetration of acid liquor to metal oxide skin, improves the whiteness of the surface, reduces color difference and reduces the generation of silicon mud.

[0039] (2) The pickling accelerator suitable for acid regeneration system adopts polyoxyethylene sorbitan monolaurate as a dispersant and polyethylene glycol octylphenyl ether as a stabilizer, so that the content of silicon dioxide in regenerated acid can be reduced, and the generation of silicon mud can be reduced.

[0040] (3) The weight ratio of the dispersant to the stabilizer in the pickling accelerator is 8:35, so that the silicon mud generated by the aggregation of silicates in the acid liquid can be effectively reduced, the deposition of the silicon mud on the equipment such as pipelines, filter screens, valves and heat exchangers in the regeneration system can be prevented, and the blockage of nozzles and pipelines can be reduced.

[0041] (4) The pickling accelerator is applied to the pickling process of silicon steel, and under the condition that no reducing agent is contained, the pickling speed of the silicon steel can be increased by 30%-50%, so that the pickling efficiency of the silicon steel is improved, and the difficulty of waste acid treatment is reduced.

[0042] (5) The pickling accelerator suitable for acid regeneration system has high purity of regenerated acid after silicon steel pickling, improves the quality of iron oxide powder, a byproduct of the acid regeneration system, and improves the economic efficiency of resource recycling. DETAILED DESCRIPTION

[0043] Examples and Comparative Examples

[0044] A pickling accelerator suitable for an acid regeneration system is prepared from raw materials in the following Table 1-2 in terms of weight percentage, and the parameters of the use method of the pickling accelerator are shown in Table 1-2.

[0045] Table 1

[0046]

[0047]

[0048] Table 2

[0049]

[0050]

[0051] The heptadecenyl amine ethyl imidazoline quaternary ammonium salt is purchased from Hubei Comaid Chemical Co., Ltd., and the brand is ODD.

[0052] The polyoxyethylene sorbitan monolaurate is Tween 20, and the CAS number is 9005-64-5.

[0053] The polyacrylic acid sodium is purchased from Dow Chemical, and the brand is ACUSOL 445N Polymer.

[0054] The polyethylene glycol octylphenyl ether is purchased from Haian Petroleum Chemical Co., Ltd., and the brand is Triton X-100.

[0055] The polyoxyethylene mono-tert-octyl phenyl ether is purchased from Hai'an Petroleum Chemical Industry, and the brand is Triton X-114.

[0056] The propylene glycol block polyether is purchased from Hai'an Petroleum Chemical Industry, and the brand is L-64.

[0057] A preparation method of an acid pickling promoter suitable for an acid regeneration system, comprising the following steps:

[0058] S1: water is added to start stirring, and a penetrating agent is added under stirring;

[0059] S2: then, a stripping agent, a dispersing agent, a stabilizing agent and a foam controller are sequentially added, and mixed and stirred uniformly to obtain the acid pickling promoter.

[0060] The use method of the acid pickling promoter, comprising the following steps: the acid pickling promoter is added into acid liquor, mixed uniformly, and silicon steel is pickled in the acid liquor added with the acid pickling promoter.

[0061] The acid liquor is hydrochloric acid, the pickling concentration is the concentration of hydrochloric acid, and the silicon steel is SWB1300 non-oriented electrical steel, which is purchased from Guiwansteel.

[0062] Performance test

[0063] 1. After pickling, the reflectivity of the plate surface: a C84-III type reflectivity tester is used to detect the reflectivity of the plate surface at three positions of the driving side, the middle side and the operation side (5-6 points are detected at each position to obtain the average value), and the average value of the reflectivity of the plate surface at the driving side, the middle side and the operation side is taken as the result. The standard reflectivity is greater than 80%.

[0064] 2. The plate surface is detected by using a Mayeda CR-10plus color difference instrument, and the color difference value ΔE of the plate surface at the driving side, the operation side and the middle side is detected (5-6 points are detected at each position to obtain the average value), and the average value of the color difference ΔE is taken as the result. The standard color difference ΔE of the plate surface after pickling is less than or equal to 1.5.

[0065] 3. The amount of silicon mud produced: after the pickling line runs continuously for 5 days, the silicon mud is collected and weighed in the tank, and the total weight of the silicon mud is divided by the total amount of silicon steel pickled in the period (tons) to obtain the amount of silicon mud produced per ton of silicon steel pickled. The standard amount of silicon mud produced is less than 0.6 kg / t of silicon steel.

[0066] 4. The content of silicon dioxide in the regenerated acid: the content of silicon dioxide in the regenerated acid is detected by using the ammonium molybdate spectrophotometric method. The standard content of silicon dioxide in the regenerated acid is less than 50 ppm. The regenerated acid is the acid liquor collected after pickling.

[0067] 5. The content of silicon dioxide in the acid regeneration byproduct iron oxide powder: The content of silicon dioxide was detected according to HG / T 2574-2009 Industrial Iron Oxide 6. The content of silicon dioxide in the qualified product of type I iron oxide powder was ≤0.015%. The acid regeneration byproduct iron oxide powder was collected after the waste acid of the acid regeneration system was treated.

[0068] The test results are shown in Table 3.

[0069] Table 3

[0070]

[0071]

[0072] When the pickling accelerator addition concentration was 0, the reflectivity of the plate surface after pickling was 68.9%, the color difference ΔE of the plate surface after pickling was 2.2, the amount of silicon mud produced was 0.67 kg / t of silicon steel, the content of silicon dioxide in the regenerated acid was 58 ppm, and the content of silicon dioxide in the acid regeneration byproduct iron oxide powder was 0.028%.

Claims

1. A pickling accelerator suitable for use in an acid regeneration system, characterized in that, The raw materials are prepared in weight percentage including: 6-17% penetrating agent, 1-5% peeling agent, 5-10% dispersing agent, 1-5% stabilizing agent, 1-3% foam control agent and water to 100%; The penetrating agent is lauryl hydroxyethyl imidazoline; The peeling agent is lauryl hydroxy sulfobetaine; The dispersing agent is polyoxyethylene sorbitan monolaurate; The stabilizing agent is polyethylene glycol octyl phenyl ether.

2. The pickling promoter suitable for acid regeneration system as claimed in claim 1 wherein, The weight percentage of the peeling agent is 2-4%.

3. The pickling promoter for use in an acid regeneration system according to claim 1, characterized in that, The weight percentage of the dispersing agent is 6-9%.

4. The pickling promoter for use in an acid regeneration system according to claim 1, wherein The weight percentage of the stabilizing agent is 2-4%.

5. The pickling promoter for use in an acid regeneration system according to claim 1, wherein The foam control agent includes at least one of propylene glycol block polyether, polyoxyethylene polyoxypropylene block polyether, dimethicone or carbon alcohol defoaming agent.

6. A process for the preparation of pickling accelerators suitable for use in acid regeneration systems according to any one of claims 1 to 5, characterized in that, The method comprises the following steps: S1: add water to start stirring, and add the penetrating agent under stirring condition; S2: then add the peeling agent, the dispersing agent, the stabilizing agent and the foam control agent in sequence, mix and stir uniformly to obtain the pickling promoter.

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