Steel slag dissolution promoting method based on complexing solubilizing effect

Abstract

The invention discloses a steel slag dissolution promoting method based on a complexing solubilizing effect, and belongs to the field of low-carbon solid waste cementing materials. The raw materials of the steel slag hydration promotion modification complexing agent comprise dihydric alcohol amine, organic acid, a catalyst and a polymerization inhibitor. The amino group in dihydric alcohol amine and the carboxyl group in the organic acid are subjected to amidation reaction, so that the molecular structure of alcohol amine is changed, the complexing ability of alcohol amine is optimized, and the effect of further promoting hydration and dissolution of the steel slag is achieved. The multi-element amide type steel slag hydration promotion modification complexing agent prepared by the invention can effectively promote the dissolution of ions in steel slag through a complexing solubilization mechanism under an alkaline condition, is beneficial to promoting the hydration reaction of the steel slag, and realizes the improvement of the gelling performance of the steel slag.

Description

Technical Field

[0001] The invention relates to the field of low-carbon solid waste cementitious materials, and in particular to a method for promoting the dissolution of steel slag based on a complexing solubilization effect. Background Art

[0002] Steel slag is a common type of industrial by-product. Globally, the amount of steel slag produced in the steel production process accounts for about 15% of the total steel production. However, the current effective utilization rate of steel slag is less than 30%, which has led to a large amount of land being occupied, resources being idle, and the environment being polluted. Applying steel slag to the cement industry is one of the development directions. Steel slag has the potential to be used as a supplementary cementitious material, which helps to reduce carbon dioxide emissions, and can enhance the mechanical properties of steel slag cement after adding specific admixtures; however, due to the key problems of insufficient cementitious activity and poor stability of steel slag itself, its development and application as an auxiliary cementitious material has been seriously hindered.

[0003] The poor gelling activity and stability of steel slag are mainly due to the compactness of its mineral structure, which makes it difficult to dissolve and slow to hydrate. Steel slag is mainly composed of minerals such as C3S, C2S, C4AF, C2F, RO, f-CaO and f-MgO; if the dissolution of silicon phase and aluminum-iron phase minerals is accelerated, it will be beneficial to improve the gelling activity of steel slag; if the dissolution rate of f-CaO and f-MgO is accelerated, it will be beneficial to improve the volume stability of steel slag.

[0004] The complexing effect between complexing agents and metal ions is an effective way to promote the dissolution of insoluble minerals in steel slag. If a complexing agent with moderate complexing ability is selected or the molecular structure of an existing complexing agent is designed to optimize its complexing ability, the dissolution of steel slag can be promoted through complexing solubilization, which is expected to further increase the ion concentration in the liquid phase of the steel slag slurry and promote better hydration and dissolution of the steel slag. Summary of the invention

[0005] The object of the present invention is to provide a method for promoting the dissolution of steel slag based on the complexing solubilization effect to solve the above-mentioned problems in the background technology. The present invention changes the molecular structure of the alcohol amine and optimizes its complexing ability by subjecting the amino group in the diol amine to an amidation reaction with the carboxyl group in the organic acid, thereby achieving the effect of further promoting the hydration and dissolution of steel slag.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] One of the technical solutions of the present invention is to provide a steel slag hydration-promoting modified complexing agent, wherein the raw materials include diol amine, organic acid, catalyst and inhibitor.

[0008] Preferably, the diolamine is diethanolamine and / or diisopropanolamine.

[0009] More preferably, the diolamine is diethanolamine.

[0010] Preferably, the organic acid is maleic anhydride.

[0011] Preferably, the molar ratio of the amino group in the diol amine to the carboxyl group in the organic acid is 1:1-2.5.

[0012] More preferably, the molar ratio of the amino group in the diol amine to the carboxyl group in the organic acid is 1:1.1.

[0013] Preferably, the catalyst is sulfuric acid and / or p-toluenesulfonic acid; the added amount of the catalyst is 1-2% of the total mass of the diolamine and the organic acid.

[0014] More preferably, the catalyst is p-toluenesulfonic acid; the added amount of the catalyst is 1.5% of the total mass of the diolamine and the organic acid.

[0015] Preferably, the polymerization inhibitor is hydroquinone; the addition amount of the polymerization inhibitor is 1.5% of the total mass of the diolamine and the organic acid.

[0016] The second technical solution of the present invention is to provide a method for preparing the above-mentioned steel slag hydration-promoting modified complexing agent, comprising the following steps:

[0017] The diol amine, organic acid, catalyst and polymerization inhibitor are mixed and reacted to obtain the steel slag hydration-promoting modified complexing agent.

[0018] Preferably, the reaction temperature is 100-130° C. and the reaction time is 1-2 h.

[0019] More preferably, the reaction temperature is 100° C. and the reaction time is 2 h.

[0020] The third technical solution of the present invention is to provide a method for promoting the dissolution of steel slag based on the complexing solubilization effect, wherein the above-mentioned steel slag hydration-promoting modified complexing agent is used.

[0021] Preferably, the added amount of the steel slag hydration-promoting complexing agent is 0.01-0.2% of the mass of the steel slag.

[0022] The technical principles of the present invention are as follows:

[0023] The present invention changes the molecular structure of the alcohol amine and optimizes its complexing ability by subjecting the amino group in the diol amine to an amidation reaction with the carboxyl group in the organic acid, thereby achieving the effect of further promoting the hydration and dissolution of the steel slag. The molar ratio of the carboxyl group in the organic acid in the reaction raw material to the amino group in the diol amine should be greater than 1:1, in order to ensure that all the amino groups in the chemical structure of the product are reacted, and the obtained product contains unreacted hydroxyl groups, thereby playing a role in promoting the dissolution of the steel slag.

[0024] The product prepared by the invention realizes the purpose of promoting the dissolution of steel slag through the complexation solubilization mechanism. The product will produce a complexation with the metal ions in the steel slag to promote the dissolution reaction to proceed in a positive direction, and can promote the total ion concentration of the steel slag to increase by 10%-15%.

[0025] The beneficial technical effects of the present invention are as follows:

[0026] The polyamide-type steel slag hydration-promoting modified complexing agent prepared by the present invention can effectively promote the dissolution of ions in steel slag through a complexation solubilization mechanism under alkaline conditions, which is beneficial to promoting the hydration reaction of steel slag and improving the gelling performance of steel slag.

[0027] The present invention solves the problem of insufficient dissolution capacity during the hydration process of steel slag, is expected to improve the resource utilization rate of steel slag when used as an auxiliary cementitious material, realizes high-quality resource utilization of steel slag, and has good application value. DETAILED DESCRIPTION

[0028] Now, various exemplary embodiments of the present invention are described in detail, and this detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics and embodiments of the present invention. It should be understood that the terms described in the present invention are only for describing specific embodiments and are not used to limit the present invention.

[0029] In addition, for the numerical range in the present invention, it is understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0030] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the invention pertains. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention.

[0031] The words “include,” “including,” “have,” “contain,” etc. used in the present invention are open-ended terms, meaning including but not limited to.

[0032] All raw materials used in the following examples and comparative examples of the present invention are commercially available products.

[0033] Example 1

[0034] A steel slag hydration-promoting modified complexing agent is composed of the following raw materials: 31.54 g of diethanolamine, 32.36 g of maleic anhydride (the molar ratio of the amino group in the diethanolamine to the carboxyl group in the maleic anhydride is 1:2.2), 0.96 g of p-toluenesulfonic acid and 0.96 g of hydroquinone (the added amounts of p-toluenesulfonic acid and hydroquinone are both 1.5% of the sum of the masses of diethanolamine and maleic anhydride).

[0035] The specific preparation method is as follows:

[0036] Diethanolamine, maleic anhydride, p-toluenesulfonic acid and hydroquinone were added into a three-necked flask in sequence and reacted at 110° C. for 2 h to obtain a steel slag hydration-promoting modified complexing agent (denoted as D1).

[0037] Example 2

[0038] A steel slag hydration-promoting modified complexing agent is composed of the following raw materials: 31.54 g of diethanolamine, 32.36 g of maleic anhydride (the molar ratio of the amino group in the diethanolamine to the carboxyl group in the maleic anhydride is 1:2.2), 0.96 g of concentrated sulfuric acid and 0.96 g of hydroquinone (the added amounts of the concentrated sulfuric acid and the hydroquinone are both 1.5% of the sum of the masses of the diethanolamine and the maleic anhydride).

[0039] The specific preparation method is as follows:

[0040] Diethanolamine, maleic anhydride, concentrated sulfuric acid and hydroquinone were added into a three-necked flask in sequence and reacted at 100°C for 2 hours to obtain a steel slag hydration-promoting modified complexing agent (denoted as D2).

[0041] Example 3

[0042] A steel slag hydration-promoting modified complexing agent is composed of the following raw materials: 39.96 g of diisopropanolamine, 32.36 g of maleic anhydride (the molar ratio of the amino group in the diisopropanolamine to the carboxyl group in the maleic anhydride is 1:2.2), 1.08 g of concentrated sulfuric acid and 1.08 g of hydroquinone (the added amounts of the concentrated sulfuric acid and the hydroquinone are both 1.5% of the sum of the masses of the diisopropanolamine and the maleic anhydride).

[0043] The specific preparation method is as follows:

[0044] Diisopropanolamine, maleic anhydride, concentrated sulfuric acid and hydroquinone were added into a three-necked flask in sequence and reacted at 100° C. for 2 h to obtain a steel slag hydration-promoting modified complexing agent (denoted as D3).

[0045] Example 4

[0046] A steel slag hydration-promoting modified complexing agent is composed of the following raw materials: 31.54 g of diethanolamine, 16.18 g of maleic anhydride (the molar ratio of the amino group in the diethanolamine to the carboxyl group in the maleic anhydride is 1:1.1) and 0.72 g of hydroquinone (the added amount of hydroquinone is 1.5% of the sum of the masses of diethanolamine and maleic anhydride).

[0047] The specific preparation method is as follows:

[0048] Diethanolamine, maleic anhydride and hydroquinone were added into a three-necked flask in sequence and reacted at 100°C for 1 hour to obtain a steel slag hydration-promoting modified complexing agent (denoted as D4).

[0049] Example 5

[0050] A steel slag hydration-promoting modified complexing agent is composed of the following raw materials: 31.54 g of diethanolamine, 16.18 g of maleic anhydride (the molar ratio of the amino group in the diethanolamine to the carboxyl group in the maleic anhydride is 1:1.1), 0.72 g of p-toluenesulfonic acid and 0.72 g of hydroquinone (the added amounts of p-toluenesulfonic acid and hydroquinone are both 1.5% of the sum of the masses of diethanolamine and maleic anhydride).

[0051] The specific preparation method is as follows:

[0052] Diethanolamine, maleic anhydride, p-toluenesulfonic acid and hydroquinone were added into a three-necked flask in sequence and reacted at 100° C. for 2 h to obtain a steel slag hydration-promoting modified complexing agent (denoted as D5).

[0053] Example 6

[0054] A steel slag hydration-promoting modified complexing agent is composed of the following raw materials: 31.54 g of diethanolamine, 19.12 g of maleic anhydride (the molar ratio of the amino group in the diethanolamine to the carboxyl group in the maleic anhydride is 1:1.3), 0.76 g of p-toluenesulfonic acid and 0.76 g of hydroquinone (the added amount of hydroquinone is 1.5% of the sum of the masses of diethanolamine and maleic anhydride).

[0055] The specific preparation method is as follows:

[0056] Diethanolamine, maleic anhydride, p-toluenesulfonic acid and hydroquinone were added into a three-necked flask in sequence and reacted at 100° C. for 2 h to obtain a steel slag hydration-promoting modified complexing agent (denoted as D6).

[0057] Effect verification

[0058] In order to verify the effect of the product obtained by the present invention on promoting the hydration and dissolution of steel slag, the following tests were conducted on each embodiment and comparative example. The specific test method is: D1, D2, D3, D4, D5 or D6 were added to the steel slag solution respectively, and diethanolamine (DEA) was added as a control group, and its dosage was 1% of the total mass of the steel slag. After standing for 30 minutes, the ICP ion concentration test was carried out to characterize its ability to promote the dissolution of steel slag, and the relevant data of the pure steel slag aqueous solution without adding any modifier was used as a blank control (Blank). The results are shown in Table 1.

[0059] Table 1 Changes in total ion concentration after slag dissolution for 30 min

[0060] Modified complexing agent Blank DEA D1 D2 D3 D4 D5 D6 Total ion concentration (mg / L) 621.34 649.66 685.50 683.92 689.31 697.33 713.15 701.50 Total ion concentration increase (%) - 4.56 10.33 10.07 10.94 12.23 14.78 12.90

[0061] As shown in Table 1, the best dissolution effect on steel slag was achieved when diethanolamine and maleic anhydride were selected for synthesis, the molar ratio of diethanolamine to maleic anhydride was 2:1.1, p-toluenesulfonic acid was selected as the catalyst, and hydroquinone was selected as the inhibitor. When the reaction was carried out at 100°C for 2h, the dissolution effect on steel slag was the best. Compared with the data of the Blank group and the DEA group, D1, D2, D3, D4, D5, and D6 all showed excellent dissolution effects, and the increase in ion concentration reached 10%-15%.

[0062] In order to verify the promoting effect of the product obtained by the present invention on the performance of steel slag, the following tests were conducted on each embodiment and comparative example. The specific test method is: D1, D2, D3, D4, D5 or D6 is added to the steel slag cement composite system, and diethanolamine (DEA) is added as a control group. The specific proportion is shown in Table 2, wherein the steel slag has been added with alcoholamine grinding aid. The 3d compressive strength of the system is tested, and the results are shown in Table 3.

[0063] Table 2 Mixing ratio of steel slag-cement mortar

[0064] serial number Modified complexing agent Cement / g Steel slag / g Water / g Sand / g Modified complexing agent dosage / g 1 Blank 315 135 225 1350 — 2 DEA 315 135 224.91 1350 0.09 3 D1 315 135 224.91 1350 0.09 4 D2 315 135 224.91 1350 0.09 5 D3 315 135 224.91 1350 0.09 6 D4 315 135 224.91 1350 0.09 7 D5 315 135 224.91 1350 0.09 8 D6 315 135 224.91 1350 0.09

[0065] Table 3 3d compressive strength of steel slag-cement composite system

[0066] Modified complexing agent Blank DEA D1 D2 D3 D4 D5 D6 Compressive strength / Mpa 18.24 18.55 20.47 19.98 20.30 20.57 20.89 20.22 Compressive strength increase / Mpa - +0.31 +2.23 +1.74 +2.06 +2.33 +2.65 +1.98

[0067] It can be seen from Table 3 that DEA has little effect on the 3d compressive strength of the slag-cement composite system, while the modified complexing agents obtained by modifying DEA can effectively improve the compressive strength of the system by 1.5-2.7 MPa. Among them, diethanolamine and maleic anhydride are used for synthesis, the molar ratio of diethanolamine to maleic anhydride is 2:1.1, p-toluenesulfonic acid is used as the catalyst, and hydroquinone is used as the inhibitor. When reacted at 100°C for 2h, the effect on the strength of the system is most obvious, increasing by 2.65 MPa.

[0068] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A steel slag hydration-promoting modified complexing agent, characterized in that: The raw materials include diolamine, organic acid, catalyst and inhibitor.

2. The steel slag hydration-promoting complexing agent according to claim 1, characterized in that: The diolamine is diethanolamine and / or diisopropanolamine.

3. The steel slag hydration-promoting complexing agent according to claim 1, characterized in that: The organic acid is maleic anhydride.

4. The steel slag hydration-promoting complexing agent according to claim 1, characterized in that: The molar ratio of the amino group in the diol amine to the carboxyl group in the organic acid is 1:1-2.

5.

5. The steel slag hydration-promoting complexing agent according to claim 1, characterized in that: The catalyst is sulfuric acid and / or p-toluenesulfonic acid; the added amount of the catalyst is 1-2% of the total mass of the diolamine and the organic acid.

6. The steel slag hydration-promoting complexing agent according to claim 1, characterized in that: The polymerization inhibitor is hydroquinone; the addition amount of the polymerization inhibitor is 1.5% of the total mass of the diolamine and the organic acid.

7. A method for preparing the steel slag hydration-promoting modified complexing agent according to any one of claims 1 to 6, characterized in that: The following steps are involved: The diol amine, organic acid, catalyst and polymerization inhibitor are mixed and reacted to obtain the steel slag hydration-promoting modified complexing agent.

8. The preparation method according to claim 7, characterized in that: The reaction temperature is 100-130°C and the reaction time is 1-2h.

9. A method for promoting the dissolution of steel slag based on complexing solubilization effect, characterized in that: The steel slag hydration-promoting modified complexing agent described in any one of claims 1 to 6 is used.

10. The method for promoting dissolution of steel slag according to claim 9, characterized in that: The added amount of the steel slag hydration-promoting modified complexing agent is 0.01-0.2% of the mass of the steel slag.