Recycling system for co-production of high-value products from waste sulfuric acid and waste phosphoric acid

Abstract

The utility model belongs to the technical field of chemical engineering, and particularly relates to a recovery system for co-production of high-valued products from waste sulfuric acid and waste phosphoric acid. The recovery system comprises a microfiltration device (1), an electrodialysis device (2), a nanofiltration device (3), an extraction device (4), a reverse extraction device (5), an ammonia neutralization device (6), a strong acid reverse extraction ammonium salt precipitation device (7) and an oxalic acid reverse extraction device (8), wherein the microfiltration device (1) is respectively provided with a steel industry waste sulfuric acid feed port (9) and an insoluble substance discharge port (10); and an electronic industry waste phosphoric acid feeding hole (11) and the like are formed in the extraction device (4). Through the device, the purpose of simple, efficient and high-resource recycling of waste sulfuric acid and waste phosphoric acid can be achieved.

Description

Technical Field

[0001] This utility model belongs to the field of chemical technology, specifically a high-value product recovery system for the co-production of waste sulfuric acid and waste phosphoric acid. Background Technology

[0002] Waste sulfuric acid is a common waste product generated during steel production, primarily from pickling and flue gas desulfurization processes. This waste sulfuric acid contains large amounts of metal ions such as iron, chromium, and zinc, as well as organic matter. Direct discharge without treatment will cause serious environmental harm.

[0003] In the electronic component manufacturing industry, waste phosphoric acid mainly originates from acid pickling and phosphating, surface anodizing, and chemical etching processes. During electronic component manufacturing, chemical etching is used to remove photoresist and form intricate circuits and structures on silicon wafers. Waste phosphoric acid consists of phosphoric acid and metal ions used for etching, and contains high concentrations of chemicals such as phosphoric acid, acetic acid, and nitrates.

[0004] The aforementioned waste sulfuric acid and waste phosphoric acid contain large amounts of metal resources and free acid. Direct discharge would cause environmental pollution and resource waste. Due to the inherent characteristics of these waste acids, existing technologies cannot incorporate heavy metal ion removal processes. Furthermore, most waste acids used for etching contain a significant concentration of nitric acid, which produces a large amount of yellow fumes during neutralization, posing a significant risk during disposal. Currently, waste sulfuric acid from the steel industry and waste phosphoric acid from electronics companies are typically recycled by downstream enterprises using simple neutralization methods to achieve harmlessness or simple resource recovery. For example, quicklime is added to waste phosphoric acid to prepare phosphogypsum, or liquid alkali is used to neutralize and prepare inorganic phosphates such as sodium phosphate. However, these processes are relatively complex and still do not achieve high-value recovery. Utility Model Content

[0005] The purpose of this invention is to address the problems existing in current technologies by providing a high-value product recovery system for the co-production of waste sulfuric acid and waste phosphoric acid. In this system, the microporous structure of ultrafiltration and nanofiltration membranes in membrane separation effectively filters out suspended solids, colloidal particles, and microorganisms from the waste acid. Furthermore, the selectivity and permeability of the reverse osmosis membrane separate dissolved organic matter, salts, and heavy metals from the waste acid, yielding high-purity acid.

[0006] To achieve the above-mentioned objectives, the technical solution of this utility model is as follows:

[0007] A high-value-added product recovery system for the co-production of waste sulfuric acid and waste phosphoric acid is disclosed. The recovery system includes a microfiltration device, an electrodialysis device, a nanofiltration device, an extraction device, a back-extraction device, an ammonia neutralization device, a strong acid back-extraction ammonium salt precipitation device, and an oxalic acid back-extraction device. The microfiltration device is equipped with a feed inlet for waste sulfuric acid from the steel industry and an outlet for insoluble matter. The extraction device is equipped with a feed inlet for waste phosphoric acid from the electronics industry. The microfiltration device is connected to the electrodialysis device. The electrodialysis device is connected to both the nanofiltration device and the extraction device. The extraction device is connected to the back-extraction device, the ammonia neutralization device, and the nanofiltration device. The back-extraction device is connected to both the strong acid back-extraction ammonium salt precipitation device and the oxalic acid back-extraction device.

[0008] Furthermore, an acid discharge outlet is provided on the nanofiltration device of the waste sulfuric acid and waste phosphoric acid co-production high-value product recovery system.

[0009] Furthermore, an ammonium phosphate discharge port is provided on the ammonia neutralization device of the waste sulfuric acid and waste phosphoric acid co-production high-value product recovery system.

[0010] Furthermore, a metal double salt discharge outlet is provided on the strong acid back-extraction ammonium salt precipitation device of the waste sulfuric acid and waste phosphoric acid co-production high-value product recovery system.

[0011] Furthermore, an oxalate discharge outlet is provided on the oxalate back-extraction device.

[0012] Furthermore, the microfiltration device is a microfiltration membrane separation device; this device is existing technology, and its function is to separate the insoluble matter in waste sulfuric acid from the waste sulfuric acid, send the waste sulfuric acid into an electrodialysis device, and send the insoluble matter for external treatment.

[0013] Furthermore, the electrodialysis device is an electrodialysis separation device. Electrodialysis separation devices are existing technology, and their function is to initially separate soluble salts from waste sulfuric acid after microfiltration treatment. The soluble salts are sent to an extraction device, while the waste sulfuric acid is sent to a nanofiltration device.

[0014] Furthermore, the nanofiltration device is a nanofiltration membrane separation device. Nanofiltration membrane separation devices are existing technology, and their function is to concentrate the waste sulfuric acid treated by the electrodialysis unit, and then send the concentrated waste sulfuric acid back to the steel plant for reuse.

[0015] Furthermore, the extraction device is a multi-stage extraction device. This extraction device is existing technology, using an extractant to extract metal ions from waste phosphoric acid from the electronics industry. The extract is then sent to a back-extraction unit, and the raffinate is sent to a neutralization unit or a nanofiltration unit.

[0016] Furthermore, the ammonia neutralization device is an acid-base neutralization device. Acid-base neutralization devices are existing technology, and their function is to neutralize phosphoric acid with ammonia to prepare ammonium phosphate.

[0017] Furthermore, the back-extraction device is existing technology, which uses a back-extraction agent to separate metal ions in the extract, and can produce metal double salts, ferrous oxalate and other high-value products according to market needs.

[0018] The working principle of this utility model is as follows:

[0019] Insoluble substances in waste sulfuric acid are separated by microfiltration. The waste sulfuric acid is then subjected to electrodialysis for preliminary separation of sulfuric acid and salts. Finally, it undergoes nanofiltration for further separation of sulfuric acid and salts, resulting in sulfuric acid usable in the steel industry. Waste phosphoric acid from the electronics industry is extracted using a self-made specialized extractant to extract and enrich metal ions, yielding purified acid and a solution rich in metal ions. The purified acid can be further purified by nanofiltration for reuse, or neutralized with ammonia to prepare ammonium phosphate. The solution rich in metal ions is back-extracted using a specific back-extractant to generate metal double salts and ferrous oxalate.

[0020] Compared with existing technologies, the beneficial effects of this utility model are:

[0021] (i) The use of membrane separation technology is less energy-consuming and does not produce secondary pollution compared to existing commonly used acid-base neutralization and technology.

[0022] (ii) The combined process of waste phosphoric acid and waste sulfuric acid recovery saves on equipment investment and land occupation.

[0023] (iii) Waste phosphoric acid and waste sulfuric acid are purified by membrane separation and extraction and then sent back to the electronics and steel industries for reuse, thus saving existing resources.

[0024] (iv) Waste phosphoric acid is treated with membranes and then neutralized with ammonia to produce ammonium phosphate. Metal ions in waste sulfuric acid are recovered by back-extraction to prepare high-value products. Attached Figure Description

[0025] Figure 1 This is a schematic diagram showing the connection relationship of a waste sulfuric acid and waste phosphoric acid co-production high-value product recovery system described in this utility model;

[0026] Among them, 1—microfiltration device, 2—electrodialysis device, 3—nanofiltration device, 4—extraction device, 5—back-extraction device, 6—ammonia neutralization device, 7—strong acid back-extraction ammonium salt precipitation device, 8—oxalic acid back-extraction device, 9—waste sulfuric acid feed port for steel industry, 10—insoluble matter discharge port, 11—waste phosphoric acid feed port for electronics industry, 12—acid discharge port, 13—ammonium phosphate discharge port, 14—metal double salt discharge port, and 15—ferrous oxalate discharge port. Detailed Implementation

[0027] All features disclosed in this specification, or all steps in all disclosed methods or processes, may be combined in any way, except for mutually exclusive features and / or steps.

[0028] Any feature disclosed in this specification (including the claims and abstract) may be replaced by other equivalent or similar features, unless specifically stated otherwise. That is, unless specifically stated otherwise, each feature is merely one example of a series of equivalent or similar features.

[0029] The features and performance of this utility model will be further described in detail below with reference to the embodiments.

[0030] Example 1:

[0031] like Figure 1 As shown, a high-value-added product recovery system for the co-production of waste sulfuric acid and waste phosphoric acid is disclosed. The recovery system includes a microfiltration device 1, an electrodialysis device 2, a nanofiltration device 3, an extraction device 4, a back-extraction device 5, an ammonia neutralization device 6, a strong acid back-extraction ammonium salt precipitation device 7, and an oxalic acid back-extraction device 8. The microfiltration device 1 is equipped with a waste sulfuric acid inlet 9 (for the steel industry) and an insoluble matter outlet 10. The extraction device 4 is equipped with a waste phosphoric acid inlet 11 (for the electronics industry). The microfiltration device 1 is connected to the electrodialysis device 2. The electrodialysis device 2 is connected to both the nanofiltration device 3 and the extraction device 4. The extraction device 4 is connected to the back-extraction device 5, the ammonia neutralization device 6, and the nanofiltration device 3. The back-extraction device 5 is connected to both the strong acid back-extraction ammonium salt precipitation device 7 and the oxalic acid back-extraction device 8.

[0032] Furthermore, in the aforementioned waste sulfuric acid and waste phosphoric acid co-production high-value product recovery system, an acid discharge outlet 12 is provided in the nanofiltration device 3, and the acid discharged from this outlet can be reused.

[0033] Furthermore, an ammonium phosphate discharge outlet 13 is provided on the ammonia neutralization device 6 in the aforementioned waste sulfuric acid and waste phosphoric acid co-production high-value product recovery system.

[0034] Furthermore, a metal double salt discharge outlet 14 is provided on the strong acid back-extraction ammonium salt precipitation device 7 in the aforementioned waste sulfuric acid and waste phosphoric acid co-production high-value product recovery system.

[0035] Furthermore, an oxalic acid back-extraction device 8 of the waste sulfuric acid and waste phosphoric acid co-production high-value product recovery system is provided with an oxalic acid discharge outlet 15.

[0036] Furthermore, in the aforementioned waste sulfuric acid and waste phosphoric acid co-production high-value product recovery system, the microfiltration device 1 used is a microfiltration membrane separation device.

[0037] Furthermore, in the aforementioned waste sulfuric acid and waste phosphoric acid co-production high-value product recovery system, the electrodialysis device 2 used is an electrodialysis separation device.

[0038] Furthermore, in the aforementioned waste sulfuric acid and waste phosphoric acid co-production high-value product recovery system, the nanofiltration device 3 is a nanofiltration membrane separation device.

[0039] Furthermore, in the aforementioned waste sulfuric acid and waste phosphoric acid co-production high-value product recovery system, the extraction device 4 used is a multi-stage extraction device.

[0040] Furthermore, in the aforementioned waste sulfuric acid and waste phosphoric acid co-production high-value product recovery system, the ammonia neutralization device 6 used is an acid-base neutralization device.

[0041] The process for recovering high-value products from waste sulfuric acid and waste phosphoric acid using the above-described waste sulfuric acid and waste phosphoric acid co-production high-value product recovery system is as follows:

[0042] First, waste sulfuric acid 1 from the steel industry (10-20 wt% H2SO4 and 20 wt% FeSO4 in the waste acid) is filtered to remove solid impurities. Then, it is subjected to deep impurity removal through a microfiltration device (pressure 0.1-0.25 MPa) to separate the insoluble matter from the waste sulfuric acid. The resulting waste sulfuric acid 1 is sent to an electrodialysis device, and the insoluble matter is sent for external treatment.

[0043] The function of the electrodialysis separation unit is to initially separate soluble salts from waste sulfuric acid after microfiltration treatment (current density 30-50 mA / cm³). 2 (Running for 0.5 to 3 hours), soluble salts are fed into the extraction device, and the resulting waste sulfuric acid 2 is sent into the nanofiltration device.

[0044] The nanofiltration membrane separation unit is used to concentrate the waste sulfuric acid 2 treated by the electrodialysis unit (pressure 1-6 MPa), and the concentrated waste sulfuric acid is sent back to the steel plant for reuse.

[0045] A soluble salt solution (mainly containing Fe2SO4) was extracted with an extractant and back-extracted with oxalic acid to obtain the high-value product ferrous oxalate;

[0046] An extractant is used in the extraction device to extract metal ions from waste phosphoric acid in the electronics industry. The extract is sent to the back-extraction unit, and the raffinate is sent to the neutralization unit or nanofiltration unit.

[0047] Depending on market demand, the raffinate can be used to prepare ammonium phosphate by neutralizing phosphoric acid with ammonia or concentrated by nanofiltration and then reused.

[0048] Metal ions in the extract can be separated using a back-extraction agent, and metal double salts, ferrous oxalate, and other high-value products can be produced according to market needs.

[0049] The embodiments described above merely illustrate specific implementation methods of this application, and while the descriptions are detailed and specific, they should not be construed as limiting the scope of protection of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the technical solution of this application, and these modifications and improvements all fall within the scope of protection of this application.

[0050] The background section is provided to generally present the context of this utility model. The work of the currently named inventors, the work to the extent described in this background section, and aspects described in this section that did not constitute prior art at the time of filing are neither expressly nor impliedly acknowledged as prior art to this utility model.

Claims

1. A high-value product recovery system for the co-production of waste sulfuric acid and waste phosphoric acid, characterized in that: The recovery system includes a microfiltration device (1), an electrodialysis device (2), a nanofiltration device (3), an extraction device (4), a back-extraction device (5), an ammonia neutralization device (6), a strong acid back-extraction ammonium salt precipitation device (7), and an oxalic acid back-extraction device (8); wherein, the microfiltration device (1) is provided with a waste sulfuric acid inlet (9) from the steel industry and an insoluble matter outlet (10); the extraction device (4) is provided with a waste phosphoric acid inlet (11) from the electronics industry; the microfiltration device (1) is connected to the electrodialysis device (2); the electrodialysis device (2) is connected to the nanofiltration device (3) and the extraction device (4); the extraction device (4) is connected to the back-extraction device (5), the ammonia neutralization device (6), and the nanofiltration device (3); the back-extraction device (5) is connected to the strong acid back-extraction ammonium salt precipitation device (7) and the oxalic acid back-extraction device (8).

2. The waste sulfuric acid and waste phosphoric acid co-production high-value product recovery system according to claim 1, characterized in that: An acid outlet (12) is provided in the nanofiltration device (3).

3. A high-value product recovery system for the co-production of waste sulfuric acid and waste phosphoric acid according to claim 1 or 2, characterized in that: A phosphate discharge port (13) is provided on the ammonia neutralization device (6).

4. The waste sulfuric acid and waste phosphoric acid co-production high-value product recovery system according to claim 3, characterized in that: A metal double salt outlet (14) is provided on the strong acid back-extraction ammonium salt precipitation device (7).

5. A high-value-added product recovery system for the co-production of waste sulfuric acid and waste phosphoric acid according to claim 1 or 4, characterized in that: Ferrous oxalate outlet (15) is provided on the oxalic acid back-extraction device (8).

6. The waste sulfuric acid and waste phosphoric acid co-production high-value product recovery system according to claim 5, characterized in that: The microfiltration device (1) is a microfiltration membrane separation device.

7. A high-value-added product recovery system for the co-production of waste sulfuric acid and waste phosphoric acid according to claim 1, 2, 4 or 6, characterized in that: The electrodialysis device (2) is an electrodialysis separation device.

8. The waste sulfuric acid and waste phosphoric acid co-production high-value product recovery system according to claim 7, characterized in that: The nanofiltration device (3) is a nanofiltration membrane separation device.

9. A high-value product recovery system for the co-production of waste sulfuric acid and waste phosphoric acid according to claim 1 or 8, characterized in that: The extraction device (4) is a multi-stage extraction device.

10. A high-value product recovery system for the co-production of waste sulfuric acid and waste phosphoric acid according to claim 9, characterized in that: The ammonia neutralization device (6) is an acid-base neutralization device.

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