Method for recycling and reproducing grinding material from sodium bicarbonate spray washing waste residues
By screening, dissolving, purifying, and recrystallizing the sodium bicarbonate spraying waste residue, the problems of large quantity and high cost of sodium bicarbonate spraying waste residue were solved, achieving efficient recycling of abrasives and environmental protection.
Patent Information
- Application Number
- CN202510765394.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-09
- Publication Date
- 2025-11-11
AI Technical Summary
The large volume of waste residue from sodium bicarbonate spraying, which cannot be effectively utilized, leads to high abrasive costs, insufficient market competitiveness, and significant environmental pressure.
The sodium bicarbonate washing waste residue is treated by screening, dissolving, purifying and recrystallizing. Large impurities are removed by screening, high-purity sodium bicarbonate solution is obtained by dissolving and purifying, and then cooled and crystallized to produce clinocrystalline polyhedral sodium bicarbonate abrasive, so as to achieve recycling.
It has reduced abrasive processing costs, decreased waste emissions, improved abrasive crystal quality and market competitiveness, and significantly alleviated environmental pressure.
Smart Images
Figure CN120922894A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of sodium bicarbonate abrasive processing technology, and in particular to a method for recycling sodium bicarbonate spray washing waste residue into abrasive. Background Technology
[0002] Industrial cleaning is an indispensable part of equipment processing and remanufacturing in industries such as machinery, electronics, aerospace, and food. Industrial cleaning is generally divided into two main categories: chemical cleaning and physical cleaning. Chemical cleaning refers to the use of chemical agents such as acids, alkalis, organic chelating agents, and dispersants to remove coatings, dirt, scale, rust, and other contaminants adhering to material surfaces through chemical reactions, decomposition, dissolution, corrosion, and peeling. In chemical cleaning operations, the added chemical agents, solvents, and reaction products, along with the original contaminants, form chemical cleaning waste liquid and residue. Because these waste liquids and residues cannot meet environmental standards and cannot be directly discharged, and because purification and treatment costs are high, their market share is gradually decreasing in today's increasingly stringent safety and environmental protection requirements.
[0003] Physical cleaning utilizes the principles of mechanics, acoustics, optics, electricity, and thermodynamics, relying on the application of external energy such as impact, scouring, friction, ultrasound, negative pressure, high pressure, ultraviolet light, and steam to remove dirt and coatings from the surface of objects. Among these methods, mechanical jet cleaning is the most widely used and primary method in the field of physical cleaning.
[0004] Mechanical jet cleaning typically uses compressed air to create a high-speed jet of solid abrasive particles. The intense scouring and friction generated by this high-pressure jet removes coatings, rust, and other contaminants from material surfaces. It is widely used in the cleaning of various materials, including metals and non-metals, glass, plastics, concrete, and marble, in industries such as machinery, equipment, vehicles, ships, aviation, aerospace, electronics, and food. Generally, the abrasives used in mechanical jet cleaning are solid particles such as corundum, steel grit, quartz sand, nutshells, corn cobs, and plastics. No chemical reactions occur during the cleaning process, and the composition of the contaminants remains unchanged. In many cases, through dust classification, the abrasive can be recycled online during the cleaning process, improving abrasive utilization and reducing waste emissions. In recent years, it has gained popularity and experienced rapid development in the industry.
[0005] However, physical jet cleaning technology is not a panacea. With technological advancements, the variety of materials across industries is constantly expanding, leading to increasingly higher demands and requirements for material cleaning. The high hardness and strength of traditional abrasive media, while providing strong cleaning capabilities and efficiency, can also cause mechanical damage and scratches to material surfaces. Careless cleaning can reduce the lifespan of materials due to over-cleaning, and in severe cases, even render components unusable. This poses potential risks for cleaning softer non-metallic materials, high-precision mechanical parts, highly sensitive electronic and optical components, and sensitive materials such as aircraft skin with special coatings and food trays. Furthermore, in flammable and explosive environments, using conventional abrasives for mechanical cleaning can generate sparks and static electricity, posing safety hazards. Therefore, a new type of sodium bicarbonate particle abrasive, characterized by its abrasive properties, safety (no sparks), environmental friendliness, non-toxicity, and a balance of brittleness and flexibility, has gradually entered the jet cleaning industry. Its moderate brittleness and flexibility, along with its safe and environmentally friendly cleaning characteristics, solves the troublesome problems of over-cleaning sensitive materials and ensuring safety and environmental protection in special environments. However, the abrasive properties of sodium bicarbonate, which combine brittleness and flexibility, also bring problems such as high breakage rate, difficulty in reuse, large waste discharge, high overall cleaning cost, and poor competitiveness.
[0006] Sodium bicarbonate, commonly known as baking soda, is chemically composed of sodium bicarbonate. Its suitability as an abrasive in the cleaning industry lies in its specific crystal structure and particle size. In other words, not all sodium bicarbonate products can be called abrasives; only those with a certain hardness and particle size, exhibiting a prismatic, polygonal crystal structure, qualify as abrasive products. The primary manufacturing method for sodium bicarbonate is the chemical method, commonly known as the carbonation method. This involves using soda ash (sodium carbonate) or natural alkali (sesquialkali) as raw materials, reacting them with carbon dioxide to produce a crystalline product. Chemically produced sodium bicarbonate products are mostly needle-shaped powder crystals around 100 micrometers in size, whose crystal form and particle size do not meet the requirements for blasting abrasives. In recent years, to meet the needs of flue gas desulfurization, many companies have developed large-particle sodium bicarbonate products. However, these products either have excessively large, poorly crystallized particles or are flat and lack sufficient strength, neither of which meets the requirements for blasting abrasives. In order to obtain sodium bicarbonate crystal abrasives with suitable particle size and crystal structure that meets the requirements of blasting, a sodium bicarbonate recrystallization abrasive production process has been developed in recent years. It successfully produces high-quality granular clinocrystalline polyhedral sodium bicarbonate products through dissolution and recrystallization using commercially available powdered sodium bicarbonate as raw material, and has been put into use in the blasting cleaning industry.
[0007] However, in today's industrial cleaning field, environmental protection and cost are crucial foundations for the survival and development of enterprises. For sodium bicarbonate cleaning technology, the manufacturing cost is relatively high because qualified crystalline abrasives are recycled products made from conventional materials through special processing. Furthermore, the brittle and flexible nature of sodium bicarbonate results in a high breakage rate, making online recycling in spray cleaning operations difficult. This leads to relatively large abrasive consumption and waste generation, resulting in higher overall cleaning costs compared to other traditional abrasives. Consequently, its advantages are diminished, hindering its widespread adoption and development.
[0008] Comprehensive analysis shows that sodium bicarbonate spray cleaning technology belongs to the category of physical jet cleaning. No chemical reaction occurs during the cleaning process. Under normal circumstances, the cleaning waste contains only a small amount of coating or paint debris removed by the washout; the majority is abrasive residue broken off during the cleaning process due to impact and friction, and its chemical composition remains sodium bicarbonate. If a reasonable and practical method can be adopted to recycle the sodium bicarbonate and reprocess it into abrasive for use in sodium bicarbonate cleaning technology, the important problem of high abrasive costs can be effectively solved, further enhancing market competitiveness. Simultaneously, waste emissions will be significantly reduced, resulting in significant environmental benefits. Summary of the Invention
[0009] This invention provides a method for recycling sodium bicarbonate spraying waste residue into abrasives, which can overcome the difficulties in the prior art where the amount of sodium bicarbonate spraying waste residue is large and cannot be utilized, thereby solving the problem of high processing cost of sodium bicarbonate abrasives.
[0010] To address the above problems, this invention provides a method for recovering sodium bicarbonate spray washing waste residue, comprising the following steps:
[0011] Step a. Spray the waste residue with sodium bicarbonate, then screen it to remove large impurities and collect the first waste residue with small particles.
[0012] Step b. Add the first waste residue to the dissolving tank, add water to fully dissolve it, and obtain the first solution;
[0013] Step c. Purify the first solution and collect the purified liquid;
[0014] Step d. Cool the purified solution to obtain sodium bicarbonate recrystallization.
[0015] In this invention, the purification method may be natural sedimentation, clarification or mechanical filtration, but is not limited to these.
[0016] In an optional embodiment of the present invention, in step a, the sieving process is set to be performed using a sieve with an aperture of 30-50 mesh.
[0017] In an optional embodiment of the present invention, in step b, the first waste residue is dissolved in water at a temperature of 55°C-60°C.
[0018] In an optional embodiment of the present invention, step b further includes: detecting the sodium bicarbonate concentration of the first solution to achieve a concentration of 14%wt-16%wt.
[0019] In an optional embodiment of the present invention, in step c, the residual impurity content of the purified liquid is set to 0.005% wt-0.01% wt. In an optional embodiment of the present invention, in step c, the remaining impurities in the first solution are dehydrated and washed, and the filtrate after impurity removal is returned to the dissolving tank in step b.
[0020] In an optional embodiment of the present invention, in step d, the purified liquid is subjected to cooling and crystallization treatment to obtain climatic polyhedral sodium bicarbonate.
[0021] In an optional embodiment of the present invention, after the purification liquid undergoes crystallization treatment, it is filtered and separated, the filtrate is returned to the dissolving tank, and the filter residue is dried to obtain the oblique crystalline polyhedral sodium bicarbonate.
[0022] In an optional embodiment of the present invention, the dried oblique crystalline polyhedral sodium bicarbonate is then sieved through multiple layers of sieves to obtain the oblique crystalline polyhedral sodium bicarbonate with a preset particle size.
[0023] In an optional embodiment of the present invention, the multi-layer sieve is configured to include at least sieves with apertures of 50 mesh, 80 mesh, 100 mesh and 150 mesh arranged from top to bottom, and the preset particle size includes 80 mesh and 100 mesh.
[0024] The present invention has the following beneficial effects:
[0025] The core technology of "solid-phase primary screening and solution-liquid phase secondary separation" for sodium bicarbonate spray washing waste residue creates favorable preconditions for the recovery, abrasive reprocessing, and recycling of sodium bicarbonate in the waste residue. It not only avoids a large waste of useful sodium bicarbonate resources and effectively reduces the processing cost of abrasives, but also produces sodium bicarbonate abrasives with a typical clinocrystalline polyhedral structure, whose crystal quality far exceeds that of similar domestic products, greatly increasing the market competitiveness of sodium bicarbonate cleaning technology. At the same time, it significantly reduces the amount of cleaning waste residue discharged for treatment, significantly alleviates environmental pressure, and has good social benefits. Attached Figure Description
[0026] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.
[0027] Figure 1 This is a schematic diagram illustrating the process principle of the sodium bicarbonate spraying waste recovery method of the present invention. Detailed Implementation
[0028] In the description of this specification, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that the specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.
[0029] This invention provides a method for recycling sodium bicarbonate spraying waste residue into abrasives, comprising the following steps:
[0030] Step a. Spray the waste residue with sodium bicarbonate, then screen it to remove large impurities and collect the first waste residue with small particles.
[0031] Step b. Add the first waste residue to the dissolving tank, add water to fully dissolve it, and obtain the first solution;
[0032] Step c. Purify the first solution and collect the purified liquid;
[0033] Step d. Cool the purified solution to obtain sodium bicarbonate recrystallization.
[0034] In sodium bicarbonate blast cleaning operations, the sodium bicarbonate abrasive residue broken by impact and friction was found to be a mixture of sodium bicarbonate and coating fragments. Since the amount of abrasive used in cleaning far exceeds the amount of coating fragments detached, and the waste residue is predominantly sodium bicarbonate, direct disposal would result in significant resource waste.
[0035] This application uses sieving, dissolving and purifying processes to obtain a high-purity sodium bicarbonate solution. Subsequently, a cooling crystallization process is used to reprocess the solution into abrasive for recycling. This process not only turns waste into treasure, making full use of the waste sodium bicarbonate components, reducing resource waste and production costs, but also significantly reduces the amount of waste residue discharged.
[0036] In an optional embodiment of the present invention, in step a, the sieving process is set to be performed using a sieve with an aperture of 30-50 mesh.
[0037] Sodium bicarbonate abrasive typically has a particle size of 50-80 mesh. After spray cleaning, the granular abrasive is damaged, and the particle size generally drops to below 150 mesh. The removed coating residue has a variety of particle sizes, some larger than 30 mesh. In this case, this application uses a sieve with a mesh size of 30-50 mesh to screen the sodium bicarbonate cleaning waste residue, preferably 30 mesh, to remove larger dirt and impurity fragments, thus playing a preliminary role in purifying the waste residue. This eliminates the risk of equipment and pipeline blockage caused by impurities entering the production system from the source, ensuring the stable operation of the subsequent production system.
[0038] In an optional embodiment of the present invention, in step b, the first waste residue is dissolved in water at a temperature of 55°C-60°C.
[0039] The first waste residue after initial screening still contains some small-particle coating impurities. When dissolved in water, the coating is insoluble in water, while sodium bicarbonate is water-soluble. In particular, using water at 55℃-60℃, preferably 58℃-60℃, can increase the dissolution rate of sodium bicarbonate, allowing it to reach complete dissolution and near saturation as quickly as possible, thereby accelerating the entire treatment process and improving the production efficiency of the recycling process.
[0040] In an optional embodiment of the present invention, step b further includes: detecting the sodium bicarbonate concentration of the first solution and maintaining it at 14%wt-16%wt.
[0041] When adding water at 58℃-60℃ to dissolve sodium bicarbonate, the concentration of sodium bicarbonate in the solution should be monitored at any time, and its total alkalinity value within this temperature range should be controlled at 14%wt-16%wt, preferably 15%wt, so that the sodium bicarbonate in the first solution is completely dissolved in a near-saturated state, so as to effectively separate it from the water-insoluble coating impurities and achieve efficient recovery of sodium bicarbonate.
[0042] In an optional embodiment of the present invention, in step c, the residual amount of impurities in the purified liquid is set to 0.005%wt-0.01%wt.
[0043] After the first solution has been allowed to stand for a preset time, the water-insoluble coating will appear as precipitate and / or suspended matter. High-purity sodium bicarbonate solution can be obtained by extracting the intermediate clear liquid. The impurity content usually does not exceed 0.005%wt-0.01%wt, and is generally no more than 0.006%wt. Therefore, the sodium bicarbonate solution has high purity, which facilitates the subsequent cooling and crystallization.
[0044] In an optional embodiment of the present invention, in step c, the remaining impurities from the first solution purification process are filtered and dehydrated, and the filtrate is returned to the dissolving tank in step b.
[0045] The purified solution of the first solution can be obtained by natural sedimentation and clarification and mechanical filtration, either alone or in combination. However, the precipitate and filter residue still contain a small amount of sodium bicarbonate. In this invention, various filter residues are collected and mixed, and the impurities are filtered and washed by filtration / water washing. The filtrate containing sodium bicarbonate is returned to the dissolving tank to improve the recovery rate of sodium bicarbonate.
[0046] The filter residue at this stage is pure coating impurities removed during the purification process. It contains virtually no sodium bicarbonate and can be discharged directly; alternatively, it can be further dried and transported.
[0047] In an optional embodiment of the present invention, in step d, the purified liquid is subjected to cooling and crystallization treatment to obtain climatic polyhedral sodium bicarbonate.
[0048] The so-called purification solution is actually a pure sodium bicarbonate solution. Circulating and cooling it allows it to recrystallize, thus obtaining a prismatic, polyhedral sodium bicarbonate crystal product. This invention uses a simple and effective purification process to reuse sodium bicarbonate in waste residue and reprocess it into abrasive for blasting cleaning, essentially recycling waste and saving raw material resources.
[0049] The cooling and crystallization of the purified solution can be achieved through external circulation cooling. When the solution reaches saturation, sodium bicarbonate crystals will be regenerated in the crystallizer. The recrystallized crystals continue to grow until they reach the required particle size. The resulting crystals are distributed in the crystallizer in a suspended state with smaller crystals at the top and larger crystals at the bottom. The crystallization operation temperature can be controlled between 40℃ and 55℃, preferably 50℃.
[0050] In an optional embodiment of the present invention, after the purification liquid undergoes crystallization treatment, it is filtered and separated, the filtrate is returned to the dissolving tank, and the filter residue is dried to obtain the oblique crystalline polyhedral sodium bicarbonate.
[0051] The filtrate from the filtration of sodium bicarbonate crystals is a saturated solution of sodium bicarbonate, which is sent to a dissolving tank for reuse in the cycle of dissolving / purifying / recrystallizing the coarse residue; while the filter residue, after drying, becomes the recrystallized product of this invention—clinic polyhedral sodium bicarbonate.
[0052] like Figure 1 As shown, a qualified sodium bicarbonate slurry is taken out from the middle of the crystallizer by a pump, thickened by a thickener, and then sent to a centrifuge for crystal-liquid separation. The resulting filter cake is wet sodium bicarbonate crystals obtained by recrystallization, with a water content of about 5%, and is sent to the subsequent drying system. The filtrate after separation is a saturated sodium bicarbonate solution, which is directly returned to the coarse slag dissolving tank for recycling.
[0053] In an optional embodiment of the present invention, the dried oblique crystalline polyhedral sodium bicarbonate is then sieved through multiple layers of sieves to obtain the oblique crystalline polyhedral sodium bicarbonate with a preset particle size.
[0054] The wet sodium bicarbonate crystals obtained after dehydration are fed into a drying tube or fluidized bed for further drying and dehydration with hot air to obtain a mixture of dry sodium bicarbonate crystals of different particle sizes. The mixed crystals are then fed into a multi-layer sieve for sieving and grading to obtain abrasive crystals of different specifications, such as 50 mesh, 80 mesh, 100 mesh, and 150 mesh. A larger mesh screen is added to the top of the upper sieve to intercept larger impurities and fragments such as equipment and pipe debris that may be mixed in during the production process. The undersize material from the bottom sieve is generally unqualified fine powder crystals. Both of these materials are composed of sodium bicarbonate and are returned to the dissolving tank for recycling.
[0055] Sodium bicarbonate crystal particles of different sizes obtained by sieving are mixed with other media as needed and then weighed and packaged by an automatic packaging machine to become finished sodium bicarbonate abrasive products of different particle size grades.
[0056] This invention collects cleaning waste residue from food dishes washed with sodium bicarbonate abrasive. Testing revealed that this waste residue is a mixture of sodium bicarbonate and coating fragments. The removed coating fragments, in dry, solid flake form, comprise approximately 2% of the waste residue. After sieving through a 30-mesh sieve, a small amount of slightly larger flake-like coating fragments were removed, leaving coarse residue. The particle size of the sodium bicarbonate abrasive decreased from an initial 50-80 mesh to below 150 mesh before and after the cleaning process, significantly smaller than the initial size, resulting in an increased angle of repose and significantly reduced fluidity. When dissolved in water at 58℃-60℃, obvious impurity fragments are insoluble in water, while sodium bicarbonate can be completely dissolved, and the solubility is not affected by impurities. During the dissolution process, a small number of impurities float on the surface of the liquid, while most sink to the bottom. After stirring, the floating matter settles down, and the precipitated impurities gather at the bottom of the bottle and can be removed by filtering with filter paper. The purified solution obtained by filtering out impurities has a purification level that meets the requirements for recrystallization. The sodium bicarbonate crystals generated by circulating cooling are indistinguishable in particle size and crystal form from sodium bicarbonate crystals made from commercially available sodium bicarbonate raw materials.
[0057] The above test data and operational experiments provide reliable data support for determining the process route of sodium bicarbonate cleaning waste residue purification, provide feasible judgment basis for the selection of scheme for recrystallization process to regenerate crystal abrasives, and also provide theoretical guidance and experimental verification for the integration of purification process with existing recrystallization process.
[0058] The present invention has the following advantages:
[0059] Based on the analysis and testing data of the waste residue from cleaning the coating of food baking pans and the simulation experiment of dissolution, purification and recrystallization, it can be seen that by adopting scientific, effective and economical purification methods to replace the purchased raw materials with sodium bicarbonate in the cleaning waste residue, and by continuing the existing recrystallization production process, it is entirely possible to remanufacture sodium bicarbonate crystal abrasive that meets the requirements of spray washing. This is the best way to solve the dual problems of high abrasive cost and difficulty in waste residue discharge at the same time.
[0060] The "solid-phase primary screening and liquid-phase secondary purification" process is the core purification technology developed by this invention for the physical properties of sodium bicarbonate cleaning waste residue. It emphasizes strengthening the pre-treatment of cleaning waste residue and allows for flexible selection, combination, or adjustment of the purification process flow, supporting equipment, and operating parameters according to different raw material qualities. This creates feasible preconditions for replacing purchased raw materials with waste residue and further broadens the range of raw material varieties and qualities that recrystallization technology can select. It is a supplement and improvement to the existing sodium bicarbonate recrystallization technology.
[0061] The production process of "solid phase primary screening, liquid phase secondary purification, and recrystallization technology to re-process abrasives" was developed on the basis of fully retaining the existing recrystallization technology. The new core purification process can achieve perfect process integration and process connection with the existing recrystallization system. The new and old systems rely on and integrate with each other. The original process flow and system equipment do not need to be changed. The separation solution and screening waste of the original recrystallization process can still be recycled according to the original process route, effectively ensuring the water balance and raw material utilization rate of the production system. The process is advanced, the process is reasonable, and the technology is reliable.
[0062] The "solid phase primary screening" technology of this invention mainly utilizes the difference in appearance and specific gravity between impurity fragments and abrasive powder. It adopts a simple and practical mechanical screening method to remove large impurities from the system inlet first, controlling the feed from the source and ensuring the smooth operation of system pipelines and equipment.
[0063] The "liquid-phase secondary purification" process of this invention makes full use of the characteristic that sodium bicarbonate is soluble in water while coating impurities are insoluble. By reasonably controlling the solubility of sodium bicarbonate, it is made completely dissolved, which not only facilitates the sedimentation, clarification and effective separation of impurities, but also simplifies the purification operation process and reduces the system solution circulation equivalent, thereby minimizing the operating costs of the purification process and subsequent crystallization process.
[0064] The core process of this invention, "solid-phase primary screening and liquid-phase secondary purification," adopts a continuous operation mode to process sodium bicarbonate cleaning waste in batches. It is economical, practical, and widely applicable. Regardless of the proportion of cleaning waste, as long as the purification process and equipment are properly selected, sodium bicarbonate raw material liquid with a quality equivalent to that of purchased raw materials can be prepared at the lowest cost. This liquid can be directly incorporated into the recrystallization production system and successively processed through subsequent circulating cooling crystallization, crystal slurry thickening separation, wet crystal drying and screening, and product mixing and packaging. This process can produce sodium bicarbonate crystal abrasive with the same crystal form and particle size as the purchased raw material, and the crystal quality far exceeds that of other abrasive products in the industry.
[0065] This invention allows for the maximum recycling of sodium bicarbonate components in waste residue, reducing raw material procurement costs to almost zero. With a recycling rate of 90%, the cost of abrasive remanufacturing can be reduced by nearly 1,000 yuan per ton. The purified and separated impurities are dehydrated, washed, collected, and dried, reducing the waste residue discharge equivalent from 1,000 kg to 50 kg, a reduction to less than 5% of the original waste residue amount, greatly alleviating environmental pressure.
[0066] Therefore, this invention not only greatly reduces the cost of abrasive processing, but also significantly reduces the amount of cleaning waste discharged. At the same time, it solves the dual problems of high raw material costs and difficulty in waste discharge. It has significant effects in cost reduction, emission reduction, energy saving and environmental protection, and has certain social significance. It creates favorable conditions for the application and market promotion of sodium bicarbonate cleaning technology.
[0067] This invention, through a production cycle model of "abrasive processing—jet cleaning—waste purification—recrystallization—abrasive reprocessing," provides an opportunity for the system integration and coordinated management of the two major industries of abrasive processing and manufacturing and abrasive cleaning services. It further improves and promotes the recrystallization technology of sodium bicarbonate abrasives. The reduction in overall cleaning costs further enhances the market competitiveness of sodium bicarbonate cleaning technology, providing another feasible path for the circular economy and sustainable development of the spray cleaning industry.
[0068] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.
Claims
1. A method for recycling sodium bicarbonate spraying waste residue into abrasives, characterized in that, Includes the following steps: Step a. Spray the waste residue with sodium bicarbonate, then screen it to remove large impurities and collect the first waste residue with small particles. Step b. Add the first waste residue to the dissolving tank, add water to fully dissolve it, and obtain the first solution; Step c. Purify the first solution and collect the purified liquid; Step d. Cool the purified solution to obtain sodium bicarbonate recrystallization.
2. The method for recovering sodium bicarbonate spray washing waste residue according to claim 1, characterized in that: In step a, the sieving process is set to be performed using a sieve with an aperture of 30-50 mesh.
3. The method for recovering sodium bicarbonate spray washing waste residue according to claim 1, characterized in that: In step b, the first waste residue is dissolved in water at a temperature of 55℃-60℃.
4. The method for recovering sodium bicarbonate spray washing waste residue according to claim 1 or 3, characterized in that: Step b further includes: detecting the sodium bicarbonate concentration of the first solution to achieve a concentration of 14%wt-16%wt.
5. The method for recovering sodium bicarbonate spray washing waste residue according to claim 1, characterized in that: In step c, the residual impurity content of the purification liquid is set to 0.005%wt-0.01%wt.
6. The method for recovering sodium bicarbonate spray washing waste residue according to claim 5, characterized in that: In step c, the remaining impurities in the first solution are dehydrated and washed, and the filtrate after impurity removal is returned to the dissolving tank described in step b.
7. The method for recovering sodium bicarbonate spray washing waste residue according to claim 1, characterized in that: In step d, the purified liquid is cooled and crystallized to obtain climatic polyhedral sodium bicarbonate.
8. The method for recovering sodium bicarbonate spray washing waste residue according to claim 7, characterized in that: After crystallization, the purified liquid is filtered and separated. The filtrate is returned to the dissolving tank, and the filter residue is dried to obtain the oblique crystalline polyhedral sodium bicarbonate.
9. The method for recovering sodium bicarbonate spray washing waste residue according to claim 8, characterized in that: The dried prismatic polyhedral sodium bicarbonate is then sieved through multiple layers of sieves to obtain prismatic polyhedral sodium bicarbonate with a preset particle size.
10. The method for recovering sodium bicarbonate spray washing waste residue according to claim 9, characterized in that: The multi-layer sieve setup includes at least sieves with apertures of 50 mesh, 80 mesh, 100 mesh, and 150 mesh arranged from top to bottom, and the preset particle size includes 80 mesh and 100 mesh.