A method for resourceful treatment of pharmaceutical high-salt high-alkali wastewater

Abstract

The application discloses a kind of resource processing methods of pharmaceutical high-salt high-alkali wastewater, comprising: step one: filtration purification;Step two: membrane method recovers mixed alkali;Step three: zinc treatment;Step four: preparation of basic zinc carbonate;Step five: salt separation and purification.The application realizes the efficient recovery and purification of alkali, zinc, sodium chloride and potassium chloride in pharmaceutical wastewater;Among them, the inorganic potassium salt binder is innovatively introduced, and the constant process conditions are matched to avoid the early precipitation of potassium salt in the component regulation and evaporation concentration process, while the recycling of membrane separation alkali is combined to greatly reduce the consumption of reagent.The wastewater treated by the application realizes the maximum recovery of resources, without secondary solid waste pollution, and the products sodium chloride, potassium chloride and basic zinc carbonate all meet the industrial standards, with a yield of more than 90%, 85% and 90% respectively, suitable for the treatment of pharmaceutical high-salt high-alkali wastewater with sodium chloride, potassium chloride, alkali and zinc as the main components, with significant economic and environmental benefits.

Description

Technical Field

[0001] This invention relates to the field of industrial wastewater treatment and resource recycling technology, and in particular to a resource-based treatment method for pharmaceutical high-salt and high-alkali wastewater. Background Technology

[0002] The pharmaceutical industry generates various types of high-concentration wastewater during production. Among these, high-salt, high-alkali wastewater, primarily composed of sodium chloride and potassium chloride, and also containing high concentrations of alkali and zinc ions, presents significant challenges for treatment due to its unique characteristics. Direct evaporation and concentration of this wastewater yields a mixed solid waste of sodium chloride, potassium chloride, hydroxides, and zinc salts, which can only be disposed of by qualified environmental protection companies. This not only results in severe resource waste but also incurs high solid waste treatment costs. Furthermore, the high concentrations of alkali and zinc in the wastewater are not effectively recovered, increasing the raw material consumption of the company's production.

[0003] In existing technologies, the traditional separation process for wastewater containing potassium chloride and sodium chloride involves repeated evaporation and concentration to precipitate salt (sodium chloride) followed by cooling to precipitate potassium (potassium chloride). However, this process has two major drawbacks: First, the production process and product quality are difficult to control accurately. After the potassium precipitation mother liquor is returned, the composition of the evaporation raw materials continues to change, and the boiling point at the end of evaporation fluctuates, which can easily lead to potassium chloride mixed in sodium chloride and sodium chloride mixed in potassium chloride, resulting in substandard product purity. Secondly, the organic matter in the wastewater, after being concentrated and enriched, can interfere with salt crystallization, further reducing product quality and making it impossible to meet industrial use standards.

[0004] Meanwhile, traditional preparation of basic zinc carbonate mostly uses the ammonia method or the soda ash method. The ammonia method is complex and requires ammonia stripping treatment, while the soda ash method requires a large amount of pure soda ash and hydrochloric acid, resulting in high raw material costs. Furthermore, it is not combined with wastewater treatment and cannot achieve the recycling of wastewater resources.

[0005] Therefore, in order to solve the technical problems of large solid waste production and resource waste caused by direct treatment of pharmaceutical high-salt and high-alkali wastewater, as well as the difficulty in controlling product quality and interference of organic matter with crystallization in traditional salt separation processes, it is urgent for those skilled in the art to provide a treatment method that can maximize the recovery of resources, achieve high-quality product purification, and reduce the consumption of reagents in pharmaceutical high-salt and high-alkali wastewater. Summary of the Invention

[0006] In view of this, the present invention provides a resource-based treatment method for pharmaceutical high-salt and high-alkali wastewater, which realizes the efficient recovery and purification of sodium bicarbonate, zinc, sodium chloride and potassium chloride in the wastewater, while achieving no secondary solid waste pollution, and has both environmental and economic value.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A method for the resource-based treatment of pharmaceutical high-salt and high-alkalinity wastewater includes the following steps: Step 1: Filtration and Purification The pharmaceutical wastewater, characterized by high salinity and alkalinity, is filtered to remove black insoluble substances, yielding refined wastewater. Step two: Membrane-based recovery of mixed alkali. Diffusion dialysis membrane separation technology is used to treat the refined wastewater and recover the mixed alkali of sodium hydroxide and potassium hydroxide in the wastewater to obtain dealkalized wastewater; Step 3: Zinc immersion treatment Adding a zinc precipitant to the dealkalization wastewater causes the zinc in the wastewater to precipitate out as zinc hydroxide. After separation by pressure filtration, solid zinc hydroxide and zinc precipitation mother liquor are obtained. Step 4: Preparation of basic zinc carbonate The mixed alkali recovered in step two is mixed with sodium bicarbonate in a certain proportion and used as a reactant to react with zinc hydroxide obtained in step three to prepare basic zinc carbonate, while simultaneously obtaining zinc production mother liquor. Step 5: Salt separation and purification After neutralizing the zinc precipitation mother liquor from step three, it is mixed with the zinc production mother liquor from step four to obtain a mixed salt mother liquor. An inorganic potassium salt binder is added to the mixed salt mother liquor, and the components are adjusted and concentrated by controlling constant process conditions. High-purity sodium chloride is precipitated first, and then the sodium removal mother liquor is cooled to precipitate high-purity potassium chloride.

[0008] Preferably, in step one, the pharmaceutical high-salt and high-alkali wastewater is filtered through a titanium filter microfiltration device or filter paper.

[0009] Preferably, in step one, the pharmaceutical high-salt and high-alkali wastewater is wastewater with a density of 1.32 g / L, pH > 14, COD 34000 ppm, and containing Na+, K+, Cl-, Zn, and OH-, with a daily treatment capacity of 5-6 m³. 3 .

[0010] Preferably, in step three, the zinc precipitation agent is sodium carbonate.

[0011] Preferably, in step four, the mixed alkali recovered in step two is mixed with sodium bicarbonate in a molar ratio of 3:2.

[0012] Preferably, in step four, the main inorganic components of the zinc-producing mother liquor are potassium chloride and sodium chloride.

[0013] Preferably, in step five, the inorganic potassium salt binder is an inorganic composite agent specifically used for potassium-sodium separation.

[0014] Preferably, in step five, the process conditions for evaporation concentration and cooling are constant parameters.

[0015] Preferably, in step five, the zinc precipitation mother liquor is neutralized with hydrochloric acid, and the pH of the mother liquor is adjusted to neutral to slightly acidic after neutralization.

[0016] Preferably, the method recovers sodium chloride with a yield of ≥90%, potassium chloride with a yield of ≥85%, and basic zinc carbonate with a yield of ≥90%, and the sodium chloride and potassium chloride are white in color, while the basic zinc carbonate meets relevant industrial standards.

[0017] The present invention achieves the following technical effects compared to the prior art: (1) Preparation of basic zinc carbonate by membrane alkali recycling + modified soda ash method: For the first time, wastewater mixed with alkali recovered from diffusion dialysis membranes was used to prepare basic zinc carbonate, replacing the pure soda ash raw material in the traditional soda ash process. When used in conjunction with sodium bicarbonate, it significantly reduced the consumption of soda ash, hydrochloric acid, and zinc precipitation agent, realizing the resource recycling of waste alkali and simplifying the preparation process of basic zinc carbonate. (2) Potassium-sodium separation technology using a special inorganic potassium salt binder and constant process conditions: We developed a proprietary inorganic potassium salt binder that can effectively prevent potassium salts from precipitating prematurely during the evaporation and concentration process. Combined with constant process parameters, it completely solves the problems of evaporation termination boiling point fluctuation and salt mixing caused by changes in raw material composition in traditional processes. At the same time, it avoids the interference of organic matter in wastewater on salt crystallization, ensuring the high purity of sodium chloride and potassium chloride. (3) The entire process is resource-based, with no secondary solid waste: Breaking through the traditional wastewater "treatment only, no recycling" model, it achieves full-component recovery of alkali, zinc, sodium chloride, and potassium chloride in wastewater. All products are industrial-grade products, with no mixed solid waste generated, truly realizing "wastewater to resources" and solving the problems of resource waste and solid waste pollution from pharmaceutical high-salt and high-alkali wastewater. (4) Strong process adaptability and stable yield: A step-by-step process was designed to address the specific water quality characteristics of pharmaceutical high-salt and high-alkalinity wastewater. Each step is tightly integrated, achieving recoveries of ≥90% sodium chloride, ≥85% potassium chloride, and ≥90% basic zinc carbonate. All product quality meets relevant industrial standards, and 5-6 cubic meters of wastewater are produced daily. 3 Its processing capacity is adapted to the actual production scale of enterprises, making it easy to implement in industrialization. Attached Figure Description

[0018] Figure 1 This is a flowchart of the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] This invention discloses a method for the resource-based treatment of pharmaceutical high-salt and high-alkalinity wastewater, specifically including the following steps: Step 1: Filtration and purification A pharmaceutical company's daily by-product of 5-6 mg 3 Pharmaceutical wastewater with high salinity and alkalinity (density 1.32 g / L, pH > 14, COD approximately 34,000 ppm, containing Na+ 146.99 g / L, K+ 55.56 g / L, Cl- 124.68 g / L, Zn 29.4 g / L, OH- 57.8 g / L, yellow in color, with an odor and suspended black insoluble matter) is filtered through a titanium filter microfiltration device or filter paper to completely remove insoluble matter from the wastewater, resulting in purified wastewater that ensures the purity of subsequent product preparation.

[0021] Step 2: Membrane recovery of mixed alkali Diffusion dialysis membrane separation technology is used to treat refined wastewater by membrane separation, and sodium hydroxide and potassium hydroxide mixed alkali are specifically recovered from the wastewater.

[0022] The recovered mixed alkali is directly recycled for subsequent basic zinc carbonate preparation processes, which not only realizes the resource utilization of waste alkali but also significantly reduces the consumption of soda ash in the basic zinc carbonate preparation process. Simultaneously, it reduces the amount of zinc precipitation agent and neutralizing hydrochloric acid used, lowering the overall reagent costs of the process. The dealkali-removing wastewater obtained after membrane separation proceeds to the next step of zinc precipitation treatment.

[0023] Step 3: Zinc immersion treatment Add a special zinc precipitation agent to the dealkali-removing wastewater, and the zinc ions in the wastewater will precipitate out in the form of zinc hydroxide precipitate through a chemical reaction; The reaction solution was separated into solid and liquid phases by pressure filtration to obtain zinc hydroxide solid filter cake and zinc precipitation mother liquor. The zinc precipitation mother liquor was then used in the subsequent salt separation process.

[0024] Step 4: Preparation of basic zinc carbonate Abandoning the traditional ammonia method and pure soda ash method for preparing basic zinc carbonate, the mixed alkali recovered in step 2 is mixed with sodium bicarbonate in a specific ratio as a reactant and reacted with the zinc hydroxide solid obtained in step 3 to prepare industrial-grade basic zinc carbonate.

[0025] The reaction also yields zinc mother liquor, whose main inorganic components are potassium chloride and sodium chloride. This zinc mother liquor is introduced into the subsequent salt separation process to achieve centralized recovery of salt resources.

[0026] Step 5: Salt separation and purification The zinc precipitation mother liquor is neutralized to neutral to weakly acidic using hydrochloric acid. The neutralized zinc precipitation mother liquor is then thoroughly mixed with the zinc production mother liquor from step 4 to obtain a mixed salt mother liquor. The inorganic potassium salt binder developed in this invention is added to the mixed salt mother liquor. This binder is an inorganic composite agent that can precisely regulate the ionic environment of the mother liquor. By controlling constant process conditions, the components of the mixed salt mother liquor with added binder are regulated and concentrated by evaporation. Under these conditions, potassium salt does not precipitate as solid salt during the evaporation and concentration process; only high-purity sodium chloride preferentially crystallizes out, thus achieving the separation and purification of sodium chloride. The mother liquor from which sodium chloride has been removed is cooled down, at which point potassium salt crystallizes out as high-purity potassium chloride, thus achieving the separation and purification of potassium chloride. The inorganic potassium salt binder used in this invention can be reused repeatedly in the salt separation system without loss or introduction of impurities, thus continuously ensuring the purity of salt crystals.

[0027] Example 1: A method for the resource-based treatment of pharmaceutical high-salt and high-alkalinity wastewater includes the following steps: Step 1: Filtration and Purification 5m 3 Pharmaceutical wastewater with high salinity and alkalinity (Na+ 146.99 g / L, K+ 55.56 g / L, Cl- 124.68 g / L, Zn 29.4 g / L, OH- 57.8 g / L, pH > 14, COD 34000 ppm) was filtered through a titanium filter microfiltration device to remove black insoluble substances and obtain refined wastewater.

[0028] Step 2: Membrane-based recovery of mixed alkali The refined wastewater is passed into a diffusion dialysis membrane separation device to recover mixed alkali (NaOH+KOH). The mixed alkali is directly collected into the basic zinc carbonate preparation reactor, and dealkali-removed wastewater is obtained after membrane separation.

[0029] Step 3: Zinc immersion treatment Add a zinc precipitant to the dealkalization wastewater, stir until zinc ions are completely precipitated, and then filter using a plate and frame filter press to obtain solid zinc hydroxide and zinc precipitate mother liquor.

[0030] Step 4: Preparation of basic zinc carbonate The recovered mixed alkali and a measured amount of sodium bicarbonate were added to the reaction vessel and stirred until dissolved. Then, solid zinc hydroxide was added. The reaction temperature was controlled at 60-70℃ and the reaction was carried out for 2-3 hours. After filtration and drying, basic zinc carbonate product was obtained, and zinc production mother liquor was also obtained.

[0031] Step 5: Salt separation and purification The zinc precipitation mother liquor was neutralized with hydrochloric acid to pH 6.5-7.0. The neutralized mother liquor was then mixed with the zinc production mother liquor to obtain a mixed salt mother liquor. Add an inorganic potassium salt binder to the mixed salt mother liquor and stir until homogeneous; Evaporation and concentration are carried out under constant evaporation temperature and pressure until sodium chloride is completely crystallized and precipitated, and then filtered to obtain high-purity sodium chloride solid. The desodium mother liquor was cooled to 20-25°C, and potassium chloride crystallized out. After filtration, high-purity potassium chloride solid was obtained. The filtered mother liquor is mixed with a new mixed salt mother liquor, and the inorganic potassium salt binder is recycled.

[0032] Implementation results: In this embodiment, 5m is processed daily. 3 The wastewater yields 2.13 tons of sodium chloride, 0.53 tons of potassium chloride, and 0.25 tons of basic zinc carbonate. Testing shows that the yields of sodium chloride, potassium chloride, and basic zinc carbonate are 90%, 85%, and 90%, respectively. The sodium chloride and potassium chloride are white in color and meet industrial salt standards, while the basic zinc carbonate complies with relevant industrial standards.

[0033] Based on 300 production days per year, 570 tons of industrial salt, 135 tons of potassium chloride, and 75 tons of basic zinc carbonate can be recycled. No mixed solid waste is generated. Membrane alkali recycling reduces soda ash consumption by more than 40% and hydrochloric acid and zinc precipitation agent consumption by more than 30%.

[0034] Beneficial effects: The method for resource-based treatment of pharmaceutical high-salt and high-alkali wastewater of the present invention has the following significant beneficial effects: 1. Maximize resource utilization: It achieves the full recovery of alkali, zinc, sodium chloride and potassium chloride in wastewater. All products are industrial-grade usable products, which completely changes the status quo of traditional treatment methods that only produce mixed solid waste. It greatly improves the resource value of wastewater and brings significant economic benefits to enterprises.

[0035] 2. Stable and controllable product quality: Through innovative design of inorganic potassium salt binder and constant process conditions, the problems of low product purity and difficult quality control in traditional salt separation processes have been solved. The recovered sodium chloride and potassium chloride have high purity and good color, and the basic zinc carbonate meets industrial standards. The products can be sold directly to external parties or used by the company itself.

[0036] 3. Significantly reduced reagent costs: Basic zinc carbonate is prepared by recycling mixed alkali through membrane separation, replacing traditional pure soda ash raw materials. At the same time, the amount of zinc precipitation agent and neutralizing hydrochloric acid used is reduced, which significantly reduces the reagent consumption of the process and further improves the economic feasibility of the process.

[0037] 4. Significant environmental benefits: This invention is a full-process resource utilization process with no secondary solid waste or secondary wastewater discharge, which completely solves the pollution problem of high-salt and high-alkali wastewater in pharmaceutical manufacturing and meets the national policy requirements for "dual carbon" and resource utilization of industrial wastewater.

[0038] 5. The process is easy to industrialize: Each step of this invention uses mature industrial equipment (titanium filter microfiltration device, diffusion dialysis membrane device, filter press, evaporation crystallization equipment, etc.), the process parameters are clear and the control is simple, with a daily output of 5-6 cubic meters. 3 Its processing capacity is adapted to the actual production scale of enterprises, making it easy to implement and promote its application in industrial settings.

[0039] Figure 1 is a process flow diagram of the pharmaceutical high-salt and high-alkali wastewater resource utilization method of the present invention. The process sequence is as follows: pharmaceutical high-salt and high-alkali wastewater → filtration and purification → membrane recovery of mixed alkali (mixed alkali is recycled to the preparation of basic zinc carbonate) → dealkali wastewater → zinc precipitation treatment → zinc hydroxide (to the preparation of basic zinc carbonate) + zinc precipitation mother liquor → neutralization of zinc precipitation mother liquor → mixing with zinc production mother liquor → addition of inorganic potassium salt binder → component regulation + evaporation and concentration → precipitation of sodium chloride → sodium removal mother liquor → cooling and temperature reduction → precipitation of potassium chloride → recycling of potassium salt binder; The preparation method of basic zinc carbonate is as follows: mixed alkali + sodium bicarbonate + zinc hydroxide → reaction → basic zinc carbonate + zinc production mother liquor (until salt separation).

[0040] Industrial applicability: This invention relates to a resource-based treatment method for pharmaceutical high-salt and high-alkali wastewater, specifically designed for pharmaceutical by-product wastewater with sodium chloride, potassium chloride, alkali, and zinc as main components. The method features clear process steps, mature equipment selection, and controllable process parameters, achieving a daily treatment capacity of 5-6 cubic meters. 3 The processing capacity is well-suited to the actual wastewater output of pharmaceutical companies, and the recovered products have clear industrial application value, bringing both economic and environmental benefits to enterprises. It possesses strong industrial practicality and promotional value.

[0041] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the technical scope of the present invention. Therefore, any minor modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for the resource-based treatment of pharmaceutical high-salt and high-alkalinity wastewater, characterized in that, Includes the following steps: Step 1: Filtration and Purification The pharmaceutical wastewater, characterized by high salinity and alkalinity, is filtered to remove black insoluble substances, yielding refined wastewater. Step two: Membrane-based recovery of mixed alkali. Diffusion dialysis membrane separation technology is used to treat the refined wastewater and recover the mixed alkali of sodium hydroxide and potassium hydroxide in the wastewater to obtain dealkalized wastewater; Step 3: Zinc immersion treatment Add a zinc precipitation agent to the dealkali-removing wastewater to cause zinc in the wastewater to precipitate out in the form of zinc hydroxide. After separation by pressure filtration, solid zinc hydroxide and zinc precipitation mother liquor are obtained. Step 4: Preparation of basic zinc carbonate The mixed alkali recovered in step two is mixed with sodium bicarbonate in a certain proportion and used as a reactant to react with zinc hydroxide obtained in step three to prepare basic zinc carbonate, while simultaneously obtaining zinc production mother liquor. Step 5: Salt separation and purification After neutralizing the zinc precipitation mother liquor from step three, it is mixed with the zinc production mother liquor from step four to obtain a mixed salt mother liquor. An inorganic potassium salt binder is added to the mixed salt mother liquor, and the components are adjusted and concentrated by controlling constant process conditions. High-purity sodium chloride is precipitated first, and then the sodium removal mother liquor is cooled to precipitate high-purity potassium chloride.

2. The method for resource-based treatment of pharmaceutical high-salt and high-alkali wastewater according to claim 1, characterized in that, In step one, the pharmaceutical high-salt and high-alkali wastewater is filtered through a titanium filter microfiltration device or filter paper.

3. The method for resource-based treatment of pharmaceutical high-salt and high-alkali wastewater according to claim 1, characterized in that, In step one, the pharmaceutical high-salt and high-alkali wastewater is defined as wastewater with a density of 1.32 g / L, pH > 14, COD 34000 ppm, and containing Na+, K+, Cl-, Zn, and OH-, with a daily treatment capacity of 5-6 m³. 3 .

4. The method for resource-based treatment of pharmaceutical high-salt and high-alkali wastewater according to claim 1, characterized in that, In step three, the zinc precipitation agent is sodium carbonate.

5. The method for resource-based treatment of pharmaceutical high-salt and high-alkali wastewater according to claim 1, characterized in that, In step four, the mixed alkali recovered in step two is mixed with sodium bicarbonate in a molar ratio of 3:

2.

6. The method for resource-based treatment of pharmaceutical high-salt and high-alkali wastewater according to claim 1, characterized in that, In step four, the main inorganic components of the zinc-producing mother liquor are potassium chloride and sodium chloride.

7. The method for resource-based treatment of pharmaceutical high-salt and high-alkali wastewater according to claim 1, characterized in that, In step five, the inorganic potassium salt binder is an inorganic composite agent specifically used for potassium-sodium separation.

8. The method for resource-based treatment of pharmaceutical high-salt and high-alkali wastewater according to claim 1, characterized in that, In step five, the process conditions for evaporation concentration and cooling are constant parameters.

9. The method for resource-based treatment of pharmaceutical high-salt and high-alkali wastewater according to claim 1, characterized in that, In step five, the zinc precipitation mother liquor is neutralized with hydrochloric acid, and the pH of the mother liquor is adjusted to neutral to slightly acidic after neutralization.

10. A method for resource-based treatment of pharmaceutical high-salt and high-alkali wastewater according to any one of claims 1-9, characterized in that, The method recovers sodium chloride with a yield of ≥90%, potassium chloride with a yield of ≥85%, and basic zinc carbonate with a yield of ≥90%. The sodium chloride and potassium chloride are white in color, and the basic zinc carbonate meets the relevant industrial standards.

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