Phosphorus-free neutral rust remover and preparation method thereof
A phosphorus-free detergent additive was prepared by combining oxaloacetic acid and polyether compounds. Combined with sodium dithionite and a dispersant, a phosphorus-free neutral rust remover was prepared. This solved the problems of low safety and corrosion of the substrate of existing rust removers, achieving efficient rust removal and reducing the phosphorus content of wastewater.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANGHAI KAIXIAN TECHNOLOGY CO LTD
- Filing Date
- 2024-02-20
- Publication Date
- 2026-06-26
AI Technical Summary
Existing rust removers have problems such as low safety, poor rust removal effect and corrosion of metal substrate. Especially in the pharmaceutical or cosmetic beverage industry, the surface of stainless steel equipment is severely rusted, and the phosphorus content of the wastewater after cleaning exceeds the standard.
A phosphorus-free detergent additive prepared by combining oxaloacetic acid and polyether compounds, combined with sodium dithionite, a phosphorus-free chelating agent and a dispersant, forms a phosphorus-free neutral rust remover. The phosphorus-free neutral rust remover is then prepared by microwave heating and grinding.
It achieves efficient removal of rust from stainless steel surfaces, avoids damage to the metal substrate, and reduces phosphorus content in wastewater, thus solving the problems of safety and poor rust removal effect.
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Figure CN118028822B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of rust removal technology, and in particular to a phosphorus-free neutral rust remover and its preparation method. Background Technology
[0002] In the pharmaceutical, cosmetics and beverage industries, stainless steel is commonly used for water purification and production equipment. However, after long-term use, the passivation layer on the surface will continue to age and disappear, and red rust will appear, increasing the risks in pharmaceutical manufacturing.
[0003] Currently, rust removers on the market are divided into acidic reagents or neutral reducing reagents. The reagent is added to the system, the circulation pump is turned on, and spray cleaning is performed to remove the rust. Regardless of the type of rust remover, they are either unsafe and have poor rust removal effects, or they contain large amounts of phosphorus, resulting in total phosphorus levels in the wastewater exceeding the standard by thousands of times. This makes direct discharge impossible; the wastewater must be collected and treated as hazardous waste. Furthermore, conventional rust removers typically use highly corrosive acids such as hydrochloric acid and nitric acid, which not only pose significant hazards but also corrode the substrate while removing rust, thus reducing the equipment's lifespan. Summary of the Invention
[0004] This application provides a phosphorus-free neutral rust remover and its preparation method to solve the technical problems of existing rust removers, such as low safety, poor rust removal effect, and corrosion of metal substrate.
[0005] In a first aspect, this application provides a phosphorus-free neutral rust remover, which, by weight, comprises the following components:
[0006] Sodium dithionite 5-10 parts, phosphate-free detergent builder 5-10 parts, dispersant 0.5-2 parts, phosphate-free chelating agent 10-20 parts, and water 67-84 parts;
[0007] The phosphorus-free detergent builder is obtained by compounding oxaloacetic acid and a polyether compound.
[0008] Furthermore, by weight, the phosphorus-free neutral rust remover comprises the following components:
[0009] 7 parts sodium dithionite, 7.5 parts phosphate-free detergent, 1.5 parts dispersant, 15 parts phosphate-free chelating agent, and 75.75 parts water.
[0010] Furthermore, the preparation method of the phosphate-free detergent builder includes the following steps:
[0011] Oxaloacetic acid was added to a polyether compound and subjected to microwave heating to obtain a mixed slurry;
[0012] The mixed slurry is ground and then dried to obtain the phosphate-free detergent additive.
[0013] Further, the weight ratio of the oxaloacetic acid to the polyether compound is (3-5):(7-10).
[0014] Furthermore, the weight ratio of the oxaloacetic acid to the polyether compound is 4.7:8.5.
[0015] Furthermore, the polyether compound is an ethylene oxide-propylene oxide block polyether.
[0016] Furthermore, the operating parameters of the microwave heating treatment include: microwave power of 500-600W, temperature of 50-60℃, time of 30-50 minutes, and stirring speed of 500-600rpm.
[0017] Furthermore, the grinding operating parameters include: a grinding speed of 350-400 rpm and a grinding time of 25-35 min.
[0018] Furthermore, the phosphorus-free chelating agent includes at least one of trisodium methylglycine diacetate and sodium polyaspartate; the dispersant includes sodium maleic acid-acrylic acid copolymer.
[0019] Secondly, this application provides a method for preparing the phosphorus-free neutral rust remover according to any one of the first aspects, the preparation method comprising the following steps:
[0020] A phosphate-free detergent builder was obtained;
[0021] The phosphorus-free detergent, sodium dithionite, phosphorus-free chelating agent, dispersant and water are mixed to obtain the phosphorus-free neutral rust remover.
[0022] The technical solutions provided in this application have at least the following advantages compared with the prior art:
[0023] This application provides a phosphorus-free neutral rust remover. The invention is prepared by compounding a specific phosphorus-free detergent builder obtained by combining oxaloacetic acid and a polyether compound, a specific reducing agent of sodium dithionite, a phosphorus-free chelating agent, and a dispersant. This phosphorus-free neutral rust remover can selectively and efficiently remove rust from stainless steel surfaces without damaging the metal substrate, solving the problems of low safety, poor rust removal effect, and corrosion of the metal substrate found in existing rust removers. Attached Figure Description
[0024] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.
[0025] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0026] Figure 1 This is a schematic flowchart illustrating a method for preparing a phosphorus-free neutral rust remover, as provided in an embodiment of this application. Detailed Implementation
[0027] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0028] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.
[0029] In a first aspect, this application provides a phosphorus-free neutral rust remover, which, by weight, comprises the following components:
[0030] Sodium dithionite 5-10 parts, phosphate-free detergent builder 5-10 parts, dispersant 0.5-2 parts, phosphate-free chelating agent 10-20 parts, and water 67-84 parts;
[0031] The phosphorus-free detergent builder is obtained by compounding oxaloacetic acid and a polyether compound.
[0032] This application provides a phosphorus-free neutral rust remover. The invention is prepared by compounding a specific phosphorus-free detergent builder obtained by combining oxaloacetic acid and a polyether compound, a specific reducing agent of sodium dithionite, a phosphorus-free chelating agent, and a dispersant. This phosphorus-free neutral rust remover can selectively and efficiently remove rust from stainless steel surfaces without damaging the metal substrate, solving the problems of low safety, poor rust removal effect, and corrosion of the metal substrate found in existing rust removers.
[0033] In some specific embodiments, the phosphorus-free neutral rust remover comprises the following components, by weight:
[0034] 7 parts sodium dithionite, 7.5 parts phosphate-free detergent, 1.5 parts dispersant, 15 parts phosphate-free chelating agent, and 75.75 parts water.
[0035] In some specific embodiments, the preparation method of the phosphate-free detergent builder includes the following steps:
[0036] Oxaloacetic acid was added to a polyether compound and subjected to microwave heating to obtain a mixed slurry;
[0037] The mixed slurry is ground and then dried to obtain the phosphate-free detergent additive.
[0038] In some specific embodiments, the weight ratio of oxaloacetic acid to the polyether compound is (3-5):(7-10).
[0039] In some specific embodiments, the weight ratio of oxaloacetic acid to the polyether compound is 4.7:8.5.
[0040] In some specific embodiments, the polyether compound is an ethylene oxide-propylene oxide block polyether, such as the commercially available BASF polyether series, with product models such as PE6100, PE6200, etc., preferably PE6100, with CAS Registry Number 9003-11-6.
[0041] In some specific embodiments, the operating parameters of the microwave heating treatment include: microwave power of 500-600W, temperature of 50-60℃, time of 30-50 minutes, and stirring speed of 500-600rpm.
[0042] In some specific embodiments, the grinding operating parameters include: a grinding speed of 350-400 rpm and a grinding time of 25-35 min.
[0043] In some specific embodiments, the phosphorus-free chelating agent includes at least one of trisodium methylglycine diacetate and sodium polyaspartate.
[0044] It should be noted that, unless otherwise specified or indicated, all raw materials for the phosphorus-free neutral rust remover provided in this application can be commercially available products, and this application document will not elaborate further.
[0045] Secondly, based on a general inventive concept, this application provides a method for preparing the phosphorus-free neutral rust remover as described in any of the claims of the first aspect, such as... Figure 1 As shown, the preparation method includes the following steps:
[0046] A phosphate-free detergent builder was obtained;
[0047] The phosphorus-free detergent, sodium dithionite, phosphorus-free chelating agent, dispersant and water are mixed to obtain the phosphorus-free neutral rust remover.
[0048] The method for preparing the phosphorus-free neutral rust remover provided in this application is simple to operate and applicable to industrial production. Furthermore, this preparation method is based on the phosphorus-free neutral rust remover described in any of the first aspects above, and therefore possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated further here.
[0049] It should be noted that, unless otherwise specified or described, the preparation method of the phosphorus-free neutral rust remover provided in this application can be carried out using conventional methods in the field, and will not be elaborated upon here. Furthermore, the phosphorus-free neutral rust remover provided in this application is generally prepared and used immediately, and during normal storage, each component can be stored separately or the solid and liquid raw materials can be stored separately.
[0050] The present application is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national standards. If there is no corresponding national standard, then general international standards, conventional conditions, or conditions recommended by the manufacturer are followed.
[0051] Example 1
[0052] This example provides a phosphorus-free neutral rust remover, which, by weight, comprises the following components: 7 parts sodium dithionite, 7.5 parts phosphorus-free detergent additive, 1.5 parts dispersant, 15 parts phosphorus-free chelating agent, and 75.75 parts water; the phosphorus-free detergent additive is obtained by compounding oxaloacetic acid and a polyether compound, the phosphorus-free chelating agent is trisodium methylglycine diacetate, and the dispersant is sodium maleic acid-acrylic acid copolymer.
[0053] The preparation method of the above-mentioned phosphorus-free neutral rust remover includes the following steps:
[0054] Step (1): Preparation of phosphate-free detergent builder:
[0055] Oxaloacetic acid was added to a polyether compound and subjected to microwave heating to obtain a mixed slurry; wherein the weight ratio of oxaloacetic acid to the polyether compound was 4.7:8.5, and the polyether compound was ethylene oxide-propylene oxide block polyether, product model PE6100; the operating parameters of the microwave heating treatment included: microwave power of 550W, temperature of 55℃, time of 40 minutes, and stirring speed of 550rpm;
[0056] The mixed slurry is ground and then dried to obtain the phosphate-free detergent additive; wherein the grinding parameters include: grinding speed of 380 rpm and grinding time of 30 min;
[0057] Step (2) Preparation of phosphorus-free neutral rust remover:
[0058] The phosphorus-free detergent additive, sodium dithionite, phosphorus-free chelating agent, dispersant and water obtained in step (1) are mixed to obtain the phosphorus-free neutral rust remover.
[0059] Example 2
[0060] This example provides a phosphorus-free neutral rust remover, which, by weight, comprises the following components: 5 parts sodium dithionite, 5 parts phosphorus-free detergent additive, 0.5 parts dispersant, 10 parts phosphorus-free chelating agent, and 84 parts water; the phosphorus-free detergent additive is obtained by compounding oxaloacetic acid and a polyether compound, the phosphorus-free chelating agent is trisodium methylglycine diacetate, and the dispersant is sodium maleic acid-acrylic acid copolymer.
[0061] The preparation method of the above-mentioned phosphorus-free neutral rust remover includes the following steps:
[0062] Step (1): Preparation of phosphate-free detergent builder:
[0063] Oxaloacetic acid was added to a polyether compound and subjected to microwave heating to obtain a mixed slurry; wherein the weight ratio of oxaloacetic acid to the polyether compound was 3:10, and the polyether compound was ethylene oxide-propylene oxide block polyether, product model PE6100; the operating parameters of the microwave heating treatment included: microwave power of 500W, temperature of 60℃, time of 30 minutes, and stirring speed of 550rpm.
[0064] The mixed slurry is ground and then dried to obtain the phosphate-free detergent additive; wherein the grinding parameters include: grinding speed of 380 rpm and grinding time of 30 min;
[0065] Step (2) Preparation of phosphorus-free neutral rust remover:
[0066] The phosphorus-free detergent additive, sodium dithionite, phosphorus-free chelating agent, dispersant and water obtained in step (1) are mixed to obtain the phosphorus-free neutral rust remover.
[0067] Example 3
[0068] This example provides a phosphorus-free neutral rust remover, which, by weight, comprises the following components: 10 parts sodium dithionite, 10 parts phosphorus-free detergent additive, 2 parts dispersant, 20 parts phosphorus-free chelating agent, and 67 parts water; the phosphorus-free detergent additive is obtained by compounding oxaloacetic acid and a polyether compound, the phosphorus-free chelating agent is sodium polyaspartate, and the dispersant is sodium maleic acid-acrylic acid copolymer.
[0069] The preparation method of the above-mentioned phosphorus-free neutral rust remover includes the following steps:
[0070] Step (1): Preparation of phosphate-free detergent builder:
[0071] Oxaloacetic acid is added to a polyether compound and microwave-treated to obtain a mixed slurry; wherein the weight ratio of oxaloacetic acid to the polyether compound is 5:7, and the polyether compound is ethylene oxide-propylene oxide block polyether, product model PE6100; the operating parameters of the microwave-treated slurry include: microwave power of 600W, temperature of 50℃, time of 50 minutes, and stirring speed of 550rpm.
[0072] The mixed slurry is ground and then dried to obtain the phosphate-free detergent additive; wherein the grinding parameters include: grinding speed of 380 rpm and grinding time of 30 min;
[0073] Step (2) Preparation of phosphorus-free neutral rust remover:
[0074] The phosphorus-free detergent additive, sodium dithionite, phosphorus-free chelating agent, dispersant and water obtained in step (1) are mixed to obtain the phosphorus-free neutral rust remover.
[0075] Comparative Example 1
[0076] This example provides a rust remover and its preparation method, which differs from Example 1 only in that sodium dithionite is replaced with sodium sulfite; the remaining steps and parameters are the same.
[0077] Comparative Example 2
[0078] This example provides a rust remover and its preparation method. The only difference from Example 1 is that the polyether compound in step (1) of preparing the phosphorus-free detergent is replaced with lauryl alcohol polyether-4, which is commercially available under the name AEO-4 and has a CAS Registry Number of 68439-50-9; the other steps and parameters are the same.
[0079] Comparative Example 3
[0080] This example provides a rust remover and its preparation method. The only difference from Example 1 is that oxaloacetic acid is replaced with oxalic acid in step (1) of preparing the phosphorus-free detergent; the other steps and parameters are the same.
[0081] Comparative Example 4
[0082] This example provides a rust remover and its preparation method, which differs from Example 1 only in that: in step (1) the weight ratio of oxaloacetic acid and polyether compound in the preparation of the phosphorus-free detergent is 8.5:4.7; the remaining steps and parameters are the same.
[0083] Comparative Example 5
[0084] This example provides a rust remover and its preparation method. The only difference from Example 1 is that step (1) of preparing the phosphorus-free detergent is adjusted to: adding oxaloacetic acid to the polyether compound and stirring and mixing at a speed of 380 rpm for 30 min to obtain the phosphorus-free detergent; wherein the weight ratio of the oxaloacetic acid to the polyether compound is 4.7:8.5; the remaining steps and parameters are the same.
[0085] Test case
[0086] At room temperature, the rust removers obtained in Examples 1-3 and Comparative Examples 1-5 were used to test the rust removal performance of 316 stainless steel. The test results are shown in Table 1.
[0087] Table 1
[0088]
[0089]
[0090] In summary, this application provides a phosphorus-free neutral rust remover and its preparation method. The phosphorus-free neutral rust remover is prepared by compounding a specific phosphorus-free detergent additive obtained by combining oxaloacetic acid and a polyether compound, a specific reducing agent of sodium dithionite, a phosphorus-free chelating agent, and a dispersant. This phosphorus-free neutral rust remover can selectively and efficiently remove rust from stainless steel surfaces without damaging the metal substrate, solving the problems of low safety, poor rust removal effect, and corrosion of the metal substrate found in existing rust removers.
[0091] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.
[0092] In this application, unless otherwise stated, directional terms such as "upper" and "lower" specifically refer to the orientation shown in the accompanying drawings. Furthermore, in the description of this application, terms such as "comprising" and "including" mean "including but not limited to". In this document, "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. A and B can be singular or plural. In this document, "at least one" means one or more, and "more than one" means two or more. "At least one", "at least one of the following", or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both represent: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can each be single or multiple.
[0093] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.
Claims
1. A phosphorus-free neutral rust remover, characterized in that, The phosphorus-free neutral rust remover comprises the following components in parts by weight: Sodium dithionite 5-10 parts, phosphate-free detergent builder 5-10 parts, dispersant 0.5-2 parts, phosphate-free chelating agent 10-20 parts, and water 67-84 parts; The phosphate-free detergent is obtained by compounding oxaloacetic acid and a polyether compound; The preparation method of the phosphorus-free detergent additive includes the following process: adding oxaloacetic acid to a polyether compound and subjecting it to microwave heating treatment to obtain a mixed slurry; The mixed slurry is ground and then dried to obtain the phosphate-free detergent additive; The weight ratio of oxaloacetic acid to the polyether compound is (3~5):(7~10). The operating parameters of the microwave heating treatment include: microwave power of 500~600W, temperature of 50~60℃, time of 30~50 minutes, and stirring speed of 500~600 rpm. The grinding parameters include: a grinding speed of 350~400 rpm and a grinding time of 25~35 min.
2. The phosphorus-free neutral rust remover according to claim 1, characterized in that, The phosphorus-free neutral rust remover comprises the following components in parts by weight: 7 parts sodium dithionite, 7.5 parts phosphate-free detergent, 1.5 parts dispersant, 15 parts phosphate-free chelating agent, and 75.75 parts water.
3. The phosphorus-free neutral rust remover according to claim 1, characterized in that, The weight ratio of oxaloacetic acid to the polyether compound is 4.7:8.
5.
4. The phosphorus-free neutral rust remover according to claim 1, characterized in that, The polyether compound is an ethylene oxide-propylene oxide block polyether.
5. The phosphorus-free neutral rust remover according to claim 1, characterized in that, The phosphorus-free chelating agent includes at least one of trisodium methylglycine diacetate and sodium polyaspartate; the dispersant includes sodium maleic acid-acrylic acid copolymer.
6. A method for preparing the phosphorus-free neutral rust remover according to any one of claims 1 to 5, characterized in that, The preparation method of the phosphorus-free neutral rust remover includes the following steps: A phosphate-free detergent builder was obtained; The phosphorus-free detergent, sodium dithionite, phosphorus-free chelating agent, dispersant and water are mixed to obtain the phosphorus-free neutral rust remover.