A controllable-release solid corrosion and scale inhibitor and its preparation method

Abstract

The present invention relates to a controllable-release solid corrosion and scale inhibitor and its preparation method, belonging to the technical field of scale inhibition materials for water treatment. The preparation method of the controllable-release solid corrosion and scale inhibitor provided by the present invention uses three metal salts (manganese nitrate, zinc nitrate, aluminum nitrate) as precursors and xanthan gum as a modifier to prepare a Mn-Zn-Al ternary modified hydrotalcite-like material through a hydrothermal reaction; further, the ternary modified hydrotalcite-like material is mixed and granulated with a scale and corrosion inhibition active component, and sieved to prepare solid corrosion and scale inhibitors of different sizes. The solid corrosion and scale inhibitor of the present invention can reduce the formation of scale while effectively delaying the corrosion of metals, and has a long-lasting action period. It can also achieve the effect of controlled release of the scale and corrosion inhibition active component, which not only helps to improve the utilization rate of water resources and reduce the dosage of water treatment additives, but also has good application prospects and development potential in the development and application of scale inhibitors for water treatment.

Description

Technical Field

[0001] The present invention relates to a controllable release solid corrosion and scale inhibitor and a preparation method thereof, belonging to the technical field of scale inhibitor materials for water treatment. Background Art

[0002] With the rapid development of modern industry, corrosion and scale inhibitors have been widely used in various water treatment environments such as domestic water and industrial circulating cooling water. Corrosion and scale inhibitors have the dual functions of corrosion inhibition and scale inhibition. On the one hand, they form a protective film on the metal surface to prevent oxidation and corrosion. On the other hand, they can reduce the deposition of scale, reduce the wear and blockage of pipelines and equipment. Therefore, the use of corrosion and scale inhibitors can not only reduce the losses caused by scale and corrosion of water-using equipment and pipelines, but also is of great significance for improving the service life of equipment, water utilization rate and heat transfer efficiency.

[0003] At present, most common corrosion and scale inhibitor products inevitably involve the use of phosphorus-containing scale inhibitor components (such as sodium ethylene diamine tetra methylene phosphonate, amino trimethylene phosphonic acid, hydroxyethylidene diphosphonic acid, polyol phosphate, 2-hydroxyphosphonoacetic acid, polyamino polyether methylene phosphonic acid, etc.). Although they can achieve good scale inhibition effects, they are not easily biodegradable and will cause pollution and harm to the natural environment after long-term use. Therefore, developing corrosion and scale inhibitors with good biological safety is an important way to improve water quality and reduce environmental pollution.

[0004] In addition, with the rapid development of the economic society, the application scenarios of scale and corrosion inhibition are gradually diversified, and the research and development focus of scale inhibitors is gradually developing towards refinement and control. Facing application scenarios with different water qualities (such as tap water, groundwater, etc.) and different pipeline materials (such as carbon steel, copper pipelines, etc.), the release requirements and application efficiency of scale inhibitor materials are different. Therefore, it is necessary to conduct controllable design on the scale and corrosion inhibition components according to actual needs, so as to achieve the purposes of high efficiency, adjustable control and improvement of material utilization rate. The controlled release strategy refers to the release process of scale inhibitor components in different environments. By controlling the dissolution rate and release rate of scale inhibitor components in different environments, the action effect of the scale inhibitor can be targeted and the dosage can be reduced. However, most of the existing corrosion and scale inhibitors have problems such as inaccurate regulation of the release rate, unstable and lasting action, and easy failure. In the actual application process, for water treatment environments with serious scaling and corrosion conditions, it is often necessary to increase the dosage and feeding frequency of the corrosion and scale inhibitor. However, the large amount and multiple use of the scale inhibitor not only increase the complexity of the operation, but also lead to excessive dissolution products, reduce the safety of the water environment, and thus greatly limit the further application of the corrosion and scale inhibitor in different water treatment environments and is not conducive to improving the utilization efficiency of scale inhibitor materials.

[0005] Therefore, there is an urgent need to develop a green and environmentally friendly corrosion and scale inhibitor with a controlled release function and stable effect to meet the refined and controllable application requirements. Summary of the Invention

[0006] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a preparation method of a solid corrosion and scale inhibitor with controlled release, which has simple process, mild conditions, and high biosafety of the prepared solid corrosion and scale inhibitor, and can timely adjust the release rate of the corrosion and scale inhibition components according to the application scenario, so as to solve the problems that the release rate of the corrosion and scale inhibitor cannot be accurately controlled and the effect is unstable.

[0007] At the same time, the purpose of the present invention is also to provide a solid corrosion and scale inhibitor with controlled release, which can reduce the formation of scale and effectively delay the corrosion of metals, and has a long-lasting action period, especially can achieve the effect of controlled release of scale and corrosion inhibition active components.

[0008] To achieve the above purpose, in the first aspect of the present invention, a preparation method of a solid corrosion and scale inhibitor with controlled release is provided, including the following steps:

[0009] (1) Mix manganese nitrate, zinc nitrate, aluminum nitrate, and xanthan gum in water, and then adjust the pH of the system to 8-10 to obtain a mixed solution; transfer the mixed solution to a high-pressure reaction kettle and carry out a hydrothermal reaction at a temperature of 110-130 °C; filter the product after the reaction, and then wash, dry, and grind to obtain modified hydrotalcite-like powder.

[0010] (2) Uniformly disperse the modified hydrotalcite-like powder in water to obtain a hydrotalcite-like dispersion; mix the scale and corrosion inhibition active components and the binder evenly to obtain an active component mixed solution; add the hydrotalcite-like dispersion to the active component mixed solution and mix evenly, and then granulate, dry, and screen to obtain solid corrosion and scale inhibitors with controlled release of different particle sizes.

[0011] In a preferred mode, in step (1), the manganese nitrate is manganese nitrate tetrahydrate; the zinc nitrate is zinc nitrate hexahydrate; the aluminum nitrate is aluminum nitrate nonahydrate.

[0012] In a preferred mode, in step (1), the molar ratio of manganese nitrate, zinc nitrate, and aluminum nitrate is 1:(0.8-1.2):(0.8-1.2), and further preferably 1:1:1. The dosage ratio of manganese nitrate, xanthan gum, and water is 0.01 mol:(2-4) g:(50-80) mL, and further preferably 0.01 mol:3 g:60 mL.

[0013] In a preferred embodiment, in step (1), the pH of the system is adjusted using ammonia water or sodium hydroxide solution. Further preferably, the mass concentration of the ammonia water is 25% - 28%, and the concentration of the sodium hydroxide solution is 0.1 - 0.5 mol / L. The hydrothermal reaction time is 2 - 4 h, and further preferably 3 h.

[0014] In a preferred embodiment, in step (2), the scale and corrosion inhibitor active components are polyepoxysuccinic acid, sodium lignosulfonate, and zinc sulfate; the mass ratio of polyepoxysuccinic acid, sodium lignosulfonate, and zinc sulfate is (4.0 - 6.0)∶(0.5 - 0.9)∶(2.0 - 2.5), and further preferably 5∶0.7∶2.3.

[0015] In a preferred embodiment, in step (2), in the hydrotalcite-like dispersion, the concentration of the modified hydrotalcite-like powder is 0.2 - 0.3 g / mL, and further preferably 0.24 g / mL.

[0016] In a preferred embodiment, in step (2), the mass ratio of the modified hydrotalcite-like powder to the scale and corrosion inhibitor active components is 3∶(3.5 - 4.5), and further preferably 3∶4.

[0017] In a preferred embodiment, in step (2), the binder is one of hydroxypropyl methylcellulose, carboxymethylcellulose, and polyvinyl alcohol; the dosage of the binder is 10% - 20% of the scale and corrosion inhibitor active components.

[0018] In a preferred embodiment, in step (2), the mesh number of the sieve used for sieving is 10 - 100 mesh. Further preferably, the mesh number of the sieve used for sieving is two or more of 10 mesh, 25 mesh, 50 mesh, 75 mesh, and 100 mesh.

[0019] In the second aspect of the present invention, a controllable release solid scale and corrosion inhibitor prepared by the above preparation method is provided.

[0020] The technical solution of the present invention has the following advantages and beneficial effects:

[0021] When preparing the solid scale and corrosion inhibitor of the present invention, three metal salts (manganese nitrate, zinc nitrate, aluminum nitrate) are used as precursors, xanthan gum is used as a modifier, and a Mn-Zn-Al ternary modified hydrotalcite-like material is prepared by hydrothermal reaction; further, the ternary modified hydrotalcite-like material is mixed with the scale and corrosion inhibitor active components for granulation and sieving to prepare solid scale and corrosion inhibitors of different sizes.

[0022] In the method of the present invention, xanthan gum undergoes ion exchange with the lamellar structure of layered double hydroxides (LDHs) during the hydrothermal reaction, and thus intercalates into the interlayer of LDHs. This not only helps to improve the structural stability of LDHs, but also helps to enhance the adsorption strength of LDHs for scale and corrosion inhibition active components, realizing the effective encapsulation of scale and corrosion inhibition active components, avoiding the sudden release and burst release of active components during use, and thus achieving the purpose of controllable adjustment of the release rate of active components.

[0023] Furthermore, the present invention uses modified LDHs as the loading matrix for scale and corrosion inhibition active components, which is beneficial to the exertion of the scale and corrosion inhibition effects of active components, and is also beneficial to improving the stability and service life of scale and corrosion inhibition active components. In particular, the present invention can select corrosion and scale inhibitors of different sizes for grading according to the actual needs of the scale inhibition environment, so as to achieve the purpose of effectively controlling the release rate and achieving the customized effect of scale and corrosion inhibition.

[0024] In addition, the preparation method of the present invention has simple process and mild conditions, and the prepared solid corrosion and scale inhibitor can be directly used for water treatment, and the use method is simple and convenient. Moreover, the solid corrosion and scale inhibitor prepared by the above method of the present invention contains no phosphorus element in the preparation raw materials, is green and environmentally friendly, and will not cause environmental pollution in the natural environment. At the same time, the present invention prepares a series of scale inhibitors with different forming sizes, and proportions the scale inhibitors of different sizes according to needs, and a series of scale inhibitor products with different release rates can be obtained. Before use, it can be controllably put in according to the predetermined scale removal requirements and release requirements, so as to realize the precise and controllable release of the scale inhibitor.

[0025] Therefore, the solid corrosion and scale inhibitor of the present invention can reduce the formation of scale, effectively delay the corrosion of metals, and has a long-lasting action period. It can also achieve the effect of controlled release of scale and corrosion inhibition active components, which not only helps to improve the utilization rate of water resources and reduce the dosage of water treatment additives, but also has good application prospects and development potential in the development and application of scale inhibitors for water treatment. Description of the Drawings

[0026] Figure 1 Results of the cumulative release rate changes of the scale inhibitors (test samples - A to C) in Example 1 of the present invention and the scale inhibitors in the control group (control samples - A to C);

[0027] Figure 2 Results of the scale inhibition rate changes of the scale inhibitor (test sample - B) in Example 1 of the present invention and the scale inhibitors in Comparative Examples 1 to 5 (comparative samples - A to E). Detailed Embodiments

[0028] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention will be further described in detail below in conjunction with specific embodiments. It should be noted that, without conflict, the features in the embodiments of the present invention can be combined with each other. Many specific details are set forth in the following description in order to fully understand the present invention. However, the present invention can also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited by the specific embodiments disclosed below. For those of ordinary skill in the art, other embodiments can also be obtained according to the provided embodiments without creative efforts. In the embodiments of the present invention, xanthan gum is from Shanghai Aladdin; the model of sodium lignosulfonate is TY-8912; polyepoxysuccinic acid is a liquid preparation with a mass content of 50%. The mass concentration of ammonia water is 25% - 28%. Other raw materials, etc., unless otherwise specified, are all commonly used materials in the art that can be obtained through commercial channels.

[0029] Example 1

[0030] A controllable-release solid corrosion and scale inhibitor, and its preparation method includes the following steps:

[0031] (1) Dissolve manganese nitrate tetrahydrate (0.01 mol), zinc nitrate hexahydrate (0.01 mol), and aluminum nitrate nonahydrate (0.01 mol) in 60 mL of deionized water, then add 3 g of xanthan gum, stir and mix for 10 min, add ammonia water to adjust the pH of the system to 9, transfer the obtained mixed solution into a high-pressure reaction kettle, and carry out hydrothermal reaction at 120 °C for 3 h; after the reaction, filter the product, wash it with deionized water until neutral, and after washing, dry the product in vacuum at 80 °C for 4 h, and then grind it to obtain a uniform powder, which is the modified hydrotalcite-like powder.

[0032] (2) Ultrasonically disperse 6 g of the modified hydrotalcite-like powder in 25 mL of deionized water to obtain a hydrotalcite-like dispersion; separately, mix 5 g of polyepoxysuccinic acid, 0.7 g of sodium lignosulfonate, 2.3 g of zinc sulfate, and 1.5 g of binder (polyvinyl alcohol) evenly under heating conditions at 40 °C to obtain an active component mixed solution. Slowly add the hydrotalcite-like dispersion to the active component mixed solution, stir and mix for 30 min, then granulate and dry, and pass through 10-mesh, 50-mesh, and 100-mesh sieves respectively to obtain spherical solid corrosion and scale inhibitors with different particle sizes (denoted as test sample - A, test sample - B, and test sample - C).

[0033] Example 2

[0034] A controllable-release solid corrosion and scale inhibitor, and its preparation method includes the following steps:

[0035] (1) Dissolve manganese nitrate tetrahydrate (0.012 mol), zinc nitrate hexahydrate (0.008 mol), and aluminum nitrate nonahydrate (0.01 mol) in 50 mL of deionized water. Then add 3.5 g of xanthan gum, stir and mix for 10 min, add ammonia water to adjust the pH of the system to 9, transfer the obtained mixed solution to a high-pressure reaction kettle, and carry out hydrothermal reaction at 120 °C for 3 h. After the reaction, filter the product, wash it with deionized water until neutral, dry the product in vacuum at 80 °C for 4 h, and then grind it to obtain a uniform powder, which is the modified hydrotalcite-like powder.

[0036] (2) Ultrasonically disperse 6 g of the modified hydrotalcite-like powder in 25 mL of deionized water to obtain a hydrotalcite-like dispersion. Separately, mix 5.5 g of polyepoxysuccinic acid, 0.5 g of sodium lignosulfonate, 2.0 g of zinc sulfate, and 1.5 g of binder (polyvinyl alcohol) evenly under heating at 40 °C to obtain an active component mixture. Slowly add the hydrotalcite-like dispersion to the active component mixture, stir and mix for 30 min, then granulate and dry, and pass through 10-mesh, 50-mesh, and 100-mesh sieves respectively to obtain spherical solid corrosion and scale inhibitors with different particle sizes.

[0037] Example 3

[0038] A controllable-release solid corrosion and scale inhibitor, and its preparation method includes the following steps:

[0039] (1) Dissolve manganese nitrate tetrahydrate (0.01 mol), zinc nitrate hexahydrate (0.012 mol), and aluminum nitrate nonahydrate (0.008 mol) in 80 mL of deionized water. Then add 4 g of xanthan gum, stir and mix for 10 min, add ammonia water to adjust the pH of the system to 9, transfer the obtained mixed solution to a high-pressure reaction kettle, and carry out hydrothermal reaction at 120 °C for 3 h. After the reaction, filter the product, wash it with deionized water until neutral, dry the product in vacuum at 80 °C for 4 h, and then grind it to obtain a uniform powder, which is the modified hydrotalcite-like powder.

[0040] (2) Ultrasonically disperse 6 g of the modified hydrotalcite-like powder in 30 mL of deionized water to obtain a hydrotalcite-like dispersion. Separately, mix 6 g of polyepoxysuccinic acid, 0.5 g of sodium lignosulfonate, 2.5 g of zinc sulfate, and 1.7 g of binder (polyvinyl alcohol) evenly under heating at 40 °C to obtain an active component mixture. Slowly add the hydrotalcite-like dispersion to the active component mixture, stir and mix for 30 min, then granulate and dry, and pass through 10-mesh, 50-mesh, and 100-mesh sieves respectively to obtain spherical solid corrosion and scale inhibitors with different particle sizes.

[0041] Example 4

[0042] A controllable-release solid corrosion and scale inhibitor, and its preparation method includes the following steps:

[0043] (1) Dissolve manganese nitrate tetrahydrate (0.01 mol), zinc nitrate hexahydrate (0.01 mol), and aluminum nitrate nonahydrate (0.01 mol) in 60 mL of deionized water. Then add 3 g of xanthan gum, stir and mix for 10 min. Add ammonia water to adjust the pH of the system to 10. Transfer the obtained mixed solution into a high-pressure reaction kettle and carry out hydrothermal reaction at 110 °C for 4 h. After the reaction, filter the product, wash it with deionized water until neutral, dry the product in vacuum at 80 °C for 4 h, and then grind it to obtain a uniform powder, which is the modified hydrotalcite-like powder.

[0044] (2) Ultrasonically disperse 6 g of the modified hydrotalcite-like powder in 25 mL of deionized water to obtain a hydrotalcite-like dispersion. Separately, mix 5 g of polyepoxysuccinic acid, 0.7 g of sodium lignosulfonate, 2.3 g of zinc sulfate, and 1.5 g of binder (polyvinyl alcohol) evenly under heating at 40 °C to obtain an active component mixed solution. Slowly add the hydrotalcite-like dispersion to the active component mixed solution, stir and mix for 30 min, then granulate and dry, and pass through 10-mesh, 50-mesh, and 100-mesh sieves respectively to obtain spherical solid corrosion and scale inhibitors with different particle sizes.

[0045] Example 5

[0046] A controllable-release solid corrosion and scale inhibitor, and its preparation method includes the following steps:

[0047] (1) Dissolve manganese nitrate tetrahydrate (0.01 mol), zinc nitrate hexahydrate (0.01 mol), and aluminum nitrate nonahydrate (0.01 mol) in 60 mL of deionized water. Then add 3 g of xanthan gum, stir and mix for 10 min. Add ammonia water to adjust the pH of the system to 8.5. Transfer the obtained mixed solution into a high-pressure reaction kettle and carry out hydrothermal reaction at 130 °C for 2 h. After the reaction, filter the product, wash it with deionized water until neutral, dry the product in vacuum at 80 °C for 4 h, and then grind it to obtain a uniform powder, which is the modified hydrotalcite-like powder.

[0048] (2) Ultrasonically disperse 6 g of the modified hydrotalcite-like powder in 25 mL of deionized water to obtain a hydrotalcite-like dispersion. Separately, mix 5 g of polyepoxysuccinic acid, 0.7 g of sodium lignosulfonate, 2.3 g of zinc sulfate, and 1.5 g of binder (polyvinyl alcohol) evenly under heating at 40 °C to obtain an active component mixed solution. Slowly add the hydrotalcite-like dispersion to the active component mixed solution, stir and mix for 30 min, then granulate and dry, and pass through 10-mesh, 50-mesh, and 100-mesh sieves respectively to obtain spherical solid corrosion and scale inhibitors with different particle sizes.

[0049] Comparative Example 1

[0050] A solid corrosion and scale inhibitor, the difference in its preparation method from that of Example 1 lies in: omitting step (1); step (2) is: ultrasonically dispersing 6 g of xanthan gum in 25 mL of deionized water to obtain a xanthan gum solution; separately, mixing 5 g of polyepoxysuccinic acid, 0.7 g of sodium lignosulfonate, 2.3 g of zinc sulfate and 1.5 g of binder (polyvinyl alcohol) evenly under the heating condition of 40 °C to obtain an active component mixture. Slowly add the xanthan gum solution to the active component mixture, stir and mix for 30 min, then granulate, dry, and pass through a 50-mesh sieve to obtain a spherical solid corrosion and scale inhibitor (denoted as Comparative Sample - A).

[0051] Comparative Example 2

[0052] A solid corrosion and scale inhibitor, the difference in its preparation method from that of Example 1 lies in: in step (1), using the same molar amount of nickel nitrate hexahydrate to replace manganese nitrate tetrahydrate; in addition, after granulating and drying in step (2), pass through a 50-mesh sieve, and the dosages of the remaining raw materials and the preparation conditions are the same as those in Example 1, and a spherical solid corrosion and scale inhibitor is prepared (denoted as Comparative Sample - B).

[0053] Comparative Example 3

[0054] A solid corrosion and scale inhibitor, the difference in its preparation method from that of Example 1 lies in: in step (1), no xanthan gum is added to obtain a hydrotalcite-like powder, and this hydrotalcite-like powder is used in step (2); in addition, after granulating and drying in step (2), pass through a 50-mesh sieve, and the dosages of the remaining raw materials and the preparation conditions are the same as those in Example 1, to obtain a solid corrosion and scale inhibitor (denoted as Comparative Sample - C).

[0055] Comparative Example 4

[0056] A solid corrosion and scale inhibitor, the difference in its preparation method from that of Example 1 lies in: in step (1), using an equal amount of sodium alginate to replace xanthan gum to obtain a modified hydrotalcite-like powder, and this modified hydrotalcite-like powder is used in step (2); in addition, after granulating and drying in step (2), pass through a 50-mesh sieve, and the dosages of the remaining raw materials and the preparation conditions are the same as those in Example 1, and a spherical solid corrosion and scale inhibitor is prepared (denoted as Comparative Sample - D).

[0057] Comparative Example 5

[0058] A solid corrosion and scale inhibitor, the difference in its preparation method from that of Example 1 lies in: xanthan gum was not added in step (1), and hydrotalcite-like powder was obtained and used in step (2); step (2) is specifically: 6 g of a mixture of hydrotalcite-like powder and xanthan gum (the mixing mass ratio of the two is 3:1) was ultrasonically dispersed in 25 mL of deionized water to obtain a mixed dispersion; separately, 5 g of polyepoxysuccinic acid, 0.7 g of sodium lignosulfonate, 2.3 g of zinc sulfate and 1.5 g of binder (polyvinyl alcohol) were mixed evenly under the heating condition of 40 °C to obtain an active component mixed solution. The mixed dispersion was slowly added to the active component mixed solution, stirred and mixed for 30 min, then granulated, dried, and passed through a 50-mesh sieve to obtain spherical solid corrosion and scale inhibitor (denoted as comparative sample - E).

[0059] Test Example 1. Determination of scale inhibition effect

[0060] Refer to GB / T 22626-2008 "Determination of Scale Inhibition Performance of Water Treatment Agents - Calcium Phosphate Deposition Method" to test the calcium phosphate scale inhibition performance of the scale inhibitors prepared in Examples 1 to 5 and Comparative Examples 1 to 5 (all with a size of 50 mesh). The dosage is 5 mg / L, and the treatment conditions are: temperature is 80 ± 1 °C, time is 10 h. The test results of calcium phosphate scale inhibition efficiency are shown in Table 1.

[0061] Refer to GB / T 16632-2019 "Determination of Scale Inhibition Performance of Water Treatment Agents - Calcium Carbonate Deposition Method" to test the calcium carbonate scale inhibition performance of the scale inhibitors prepared in Examples 1 to 5 and Comparative Examples 1 to 5 (all with a size of 50 mesh). The dosage is 5 mg / L, and the treatment conditions are: temperature 80 ± 1 °C, time is 10 h. The test results of calcium carbonate scale inhibition efficiency are shown in Table 1.

[0062] Table 1. Scale inhibition effects of different scale inhibitors on calcium phosphate and calcium carbonate

[0063]

[0064] It can be seen from the results in Table 1 that the scale inhibitors of Examples 1 to 5 of the present invention have a scale inhibition rate of over 90% for both calcium phosphate and calcium carbonate, which is better than the scale inhibitors provided by Comparative Examples 1 to 5, and the scale inhibition effect on calcium carbonate is the best.

[0065] Test Example 2. Determination of release rate and use stability

[0066] In this experiment, the solid corrosion and scale inhibitors with different particle sizes prepared in Example 1 of the present invention (test sample - A, test sample - B, test sample - C) were compared with the scale inhibitor samples prepared by the existing conventional methods in terms of release rate. Further, the solid corrosion and scale inhibitor prepared in Example 1 of the present invention (test sample - B) was compared with the solid corrosion and scale inhibitors prepared in Comparative Examples 1 - 5 (comparative sample - A - comparative sample - E) in terms of use stability.

[0067] Among them, when comparing the release rates, the scale inhibitor sample prepared by the conventional method was used as the control sample. The specific preparation process was as follows: 5 g of polyepoxysuccinic acid, 0.7 g of sodium lignosulfonate, 2.3 g of zinc sulfate, and 1.5 g of binder (polyvinyl alcohol) were mixed evenly under the heating condition of 40 °C, then granulated and dried, and passed through 10 - mesh, 50 - mesh, and 100 - mesh sieves respectively to obtain spherical solid corrosion and scale inhibitors with different particle sizes (denoted as control sample - A, control sample - B, and control sample - C respectively).

[0068] The determination process of the release rate and use stability under static conditions was as follows: 1 g of each scale inhibitor sample was weighed and packed in different gauze bags, and then placed in 1 L of simulated water environment (containing 300 mg / L of Ca 2+ , 200 mg / L of HCO¯), and the temperature was maintained at 60 ± 1 °C for static scale inhibition test. Each scale inhibitor was slowly released into the water body. After 1 day, 20 mL of the supernatant was taken to measure the concentration and scale inhibition rate of the scale inhibitor. After sampling, the gauze bag was taken out and put back into the newly prepared 1000 mL simulated water environment, and the scale inhibition test was carried out in this cycle. Samples were taken and detected on the 1st, 5th, 10th, 20th, 30th, 40th, 50th, and 60th days respectively to measure the concentration and scale inhibition rate of the scale inhibitor, and the cumulative release rate and the change curve of the scale inhibition rate of the scale inhibitor were plotted. The results are shown in Figure 1 and Figure 2 respectively.

[0069] As Figure 1 shown by the cumulative release rate test results, for the scale inhibitors with different sizes provided by the control group, at the test temperature of 60 °C, the release rates were all relatively fast, the rates were uncontrollable, and they did not have the effect of controlled release. However, for the solid corrosion and scale inhibitor provided in Example 1 of the present invention, the release rate of the large - sized scale inhibitor was slow, and the release rate of the small - sized scale inhibitor was significantly accelerated. There was an obvious gradient relationship in the release amount of the active ingredients of the scale inhibitors with different sizes, and it had an excellent controlled release effect. Therefore, the release rate of the corrosion and scale inhibition components could be adjusted timely according to the application scenario. Moreover, the release rate of the active ingredients of the scale inhibitor in Example 1 was slower than that of the control group, and it was not easy to occur sudden release and burst release phenomena, which was also beneficial to extending the effective scale inhibition days.

[0070] As Figure 2As shown in the scale inhibition rate test results, at the same dosage and the same size, the scale inhibition effects of each group of scale inhibitors decreased to varying degrees with the extension of time. Among them, the scale inhibitor provided in Example 1 of the present invention had the highest scale inhibition efficiency. After a 60-day test cycle, its scale inhibition efficiency still reached 71.3%. For the scale inhibitors provided in Comparative Examples 1-5, the scale inhibition efficiencies were 32.9%, 64.4%, 49.3%, 54.3%, and 60.8% respectively after 60 days. Therefore, the scale inhibitor of the present invention can achieve better scale inhibition effects, has good use stability, and a long effective scale inhibition time and service life.

[0071] Experimental Example 3: Determination of Corrosion Inhibition Effect

[0072] Refer to GB / T 18175-2014 "Determination of Corrosion Inhibition Performance of Water Treatment Agents - Rotating Hanging Specimen Method" to test the corrosion inhibition performance of the scale inhibitors prepared in Examples 1-5 and Comparative Examples 1-5 (all with a size of 50 mesh). The test specimens used were brass specimens. The dosage of the scale inhibitor was 50 mg / L, the temperature was 50 ± 1 °C, and the treatment time was 96 h. The test results of the brass corrosion rate and corrosion inhibition rate are shown in Table 2.

[0073] Table 2. Comparison of Corrosion Inhibition Effects of Different Scale Inhibitors

[0074]

[0075] From the comparison of the corrosion inhibition effects of the scale inhibitors in Examples 1-5 and Comparative Examples 1-5 in Table 2, it can be seen that the corrosion rate and corrosion inhibition rate of the scale inhibitors provided in the examples of the present invention are better than those of the comparative examples, indicating that the scale inhibitors of the present invention have good corrosion inhibition performance, are more conducive to reducing metal corrosion, and extending the service life of pipelines.

[0076] Based on the above test results, it can be known that the solid corrosion inhibition and scale inhibition agent of the present invention can reduce the formation of water scale and effectively delay the corrosion of metals at the same time, and its action period is persistent. In particular, it can achieve the effect of controlled release of corrosion inhibition and scale inhibition active components, which not only helps to improve the utilization rate of water resources and reduce the dosage of water treatment aids, but also has good application prospects and development potential in the development and application of water treatment scale inhibitors.

[0077] The above is only the preferred embodiment of the present invention, and it is not a limitation of the present invention in other forms. Any person skilled in the art can use the disclosed technical content to make changes or modifications into equivalent embodiments with equivalent changes. However, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention without departing from the technical solution content of the present invention still belong to the protection scope of the technical solution of the present invention.

Claims

1. A method for preparing a controlled-release solid corrosion and scale inhibitor, characterized in that: The following steps are involved: (1) Mixing manganese nitrate, zinc nitrate, aluminum nitrate and xanthan gum in water, and then adjusting the pH of the system to 8-10 to obtain a mixed solution; transferring the mixed solution to a high-pressure reactor, and performing a hydrothermal reaction at a temperature of 110-130° C.; filtering the product after the reaction, and then washing, drying and grinding to obtain a modified hydrotalcite-like powder; (2) uniformly dispersing the modified hydrotalcite-like powder in water to obtain a hydrotalcite-like dispersion; uniformly mixing the scale and corrosion inhibitor active component with a binder to obtain an active component mixed solution; adding the hydrotalcite-like dispersion to the active component mixed solution and mixing, and then granulating, drying, and sieving to obtain solid corrosion and scale inhibitors of different sizes with controlled release; The scale and corrosion inhibition active components are polyepoxysuccinic acid, sodium lignin sulfonate and zinc sulfate.

2. The method for preparing a controlled-release solid corrosion and scale inhibitor according to claim 1, characterized in that: In step (1), the manganese nitrate is manganese nitrate tetrahydrate; the zinc nitrate is zinc nitrate hexahydrate; and the aluminum nitrate is aluminum nitrate nonahydrate.

3. The method for preparing a controlled-release solid corrosion and scale inhibitor according to claim 1, characterized in that: In step (1), the molar ratio of manganese nitrate, zinc nitrate and aluminum nitrate is 1:(0.8-1.2):(0.8-1.2); the dosage ratio of manganese nitrate, xanthan gum and water is 0.01 mol:(2-4) g:(50-80) mL.

4. The method for preparing a controlled-release solid corrosion and scale inhibitor according to claim 1, characterized in that: In step (1), the pH of the system is adjusted using aqueous ammonia or sodium hydroxide solution; and the hydrothermal reaction time is 2 to 4 hours.

5. The method for preparing a controlled-release solid corrosion and scale inhibitor according to any one of claims 1 to 4, characterized in that: In step (2), the mass ratio of the polyepoxysuccinic acid, sodium lignin sulfonate and zinc sulfate is (4.0-6.0):(0.5-0.9):(2.0-2.5).

6. The method for preparing a controlled-release solid corrosion and scale inhibitor according to any one of claims 1 to 4, characterized in that: In step (2), the concentration of the modified hydrotalcite-like powder in the hydrotalcite-like dispersion is 0.2-0.3 g / mL.

7. The method for preparing a controlled-release solid corrosion and scale inhibitor according to any one of claims 1 to 4, characterized in that: In step (2), the mass ratio of the modified hydrotalcite-like powder to the scale and corrosion inhibitor active component is 3: (3.5-4.5).

8. The method for preparing a controlled-release solid corrosion and scale inhibitor according to any one of claims 1 to 4, characterized in that: In step (2), the binder is one of hydroxypropyl methylcellulose, carboxymethyl cellulose and polyvinyl alcohol; the amount of the binder is 10% to 20% of the scale and corrosion inhibition active component.

9. The method for preparing a controlled-release solid corrosion and scale inhibitor according to any one of claims 1 to 4, characterized in that: In step (2), the mesh size of the sieve used for sieving is 10-100 mesh.

10. A controlled-release solid corrosion and scale inhibitor prepared by the preparation method according to any one of claims 1 to 9.

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