System for purifying and recovering high-concentration industrial phosphoric acid from waste phosphoric acid in electronic industry

Abstract

The utility model discloses a system for purifying and recovering high-concentration industrial phosphoric acid from waste phosphoric acid in the electronic industry. The system comprises a phosphoric acid dilution tank, an inorganic ultrafiltration device, a nanofiltration device, a membrane distillation device, a single-effect evaporator and a condensed water tank. An inlet of the phosphoric acid dilution tank is connected with an outlet of the waste phosphoric acid storage tank; an inlet of the inorganic ultrafiltration device is connected with an outlet of the phosphoric acid dilution tank; an inlet of the nanofiltration device is connected with an outlet of the inorganic ultrafiltration device; an inlet of the membrane distillation device is connected with an outlet of the nanofiltration device; an inlet of the single-effect evaporator is connected with an outlet of the membrane distillation device, and an outlet of the single-effect evaporator is connected with the high-concentration phosphoric acid storage tank; an inlet of the condensed water tank is respectively connected with a distilled water outlet of the membrane distillation device and a condensed water outlet of the single-effect evaporator, and an outlet of the condensed water tank is connected with a water replenishing port of the phosphoric acid dilution tank. The device can efficiently separate pollutants and concentrate and recover phosphoric acid at the same time, has the advantages of low energy consumption, flexibility in operation, high efficiency and the like, and can generate higher market value.

Description

Technical Field

[0001] The utility model relates to a system for purifying waste phosphoric acid in the electronics industry and recovering high-concentration industrial phosphoric acid. Background Art

[0002] my country's electronics industry is rapidly developing, and demand for phosphoric acid, a key chemical, has increased significantly. Phosphoric acid in the electronics industry is primarily used in etching integrated circuits, cleaning semiconductors, and cleaning optoelectronic devices. The etched materials primarily consist of various metal oxides, silicates, and nitrides. While waste phosphoric acid is generally clear and transparent, the potential presence of metal ions and other adulterants presents a major challenge to its recovery.

[0003] Currently, waste phosphoric acid is mostly recycled by preparing phosphate products, such as calcium phosphate and urea phosphate; metal ions contained in waste phosphoric acid are removed by using cation exchange resins, adjusting pH and precipitation methods. However, cation exchange resins cannot selectively remove metal ion mixtures, and operating conditions will affect the exchange efficiency and stability of the resin; other pollutants will be generated when calcium hydroxide, activated carbon, flocculants and other impurities are added, and the pH value requires precise measurement and adjustment, which may lead to unsatisfactory treatment effects. Metal ions are easily enriched and amplified in prepared products such as calcium phosphate and urea phosphate, which also poses a great problem for the use and sale of subsequent products. At present, inorganic phosphates have high production and low prices on the market. The recycled products are under great competition and have low market value, which means that waste phosphoric acid has not been well recycled. Utility Model Content

[0004] The purpose of the utility model is to overcome the defects of the prior art and provide a system for purifying and recovering high-concentration industrial phosphoric acid from waste phosphoric acid in the electronics industry. The system can efficiently separate pollutants while concentrating and recovering phosphoric acid, has the advantages of low energy consumption, flexible operation, high efficiency, etc., and generates higher market value.

[0005] The purpose of the utility model is achieved as follows: a system for purifying and recovering high-concentration industrial phosphoric acid from waste phosphoric acid in the electronics industry, comprising a phosphoric acid dilution tank, an inorganic ultrafiltration device, a nanofiltration device, a membrane distillation device, a single-effect evaporator and a condensed water tank; wherein,

[0006] The inlet of the phosphoric acid dilution tank is connected to the outlet of the waste phosphoric acid storage tank;

[0007] The inlet of the inorganic ultrafiltration device is connected to the outlet of the phosphoric acid dilution tank;

[0008] The feed liquid inlet of the nanofiltration device is connected to the outlet of the inorganic ultrafiltration device, and the retentate of the nanofiltration device is refluxed into the phosphoric acid dilution tank;

[0009] The inlet of the membrane distillation device is connected to the permeate outlet of the nanofiltration device;

[0010] The inlet of the single-effect evaporator is connected to the outlet of the membrane distillation device, and the outlet of the single-effect evaporator is connected to the high-concentration phosphoric acid storage tank;

[0011] The inlet of the condensed water tank is connected to the distilled water outlet of the membrane distillation device and the condensed water outlet of the single-effect evaporator respectively, and the outlet of the condensed water tank is connected to the water supply port of the phosphoric acid dilution tank.

[0012] In the above-mentioned system for purifying waste phosphoric acid from the electronics industry and recovering high-concentration industrial phosphoric acid, the membrane distillation device and the single-effect evaporator are both heated by factory waste heat.

[0013] In the above-mentioned system for purifying waste phosphoric acid in the electronics industry and recovering high-concentration industrial phosphoric acid, the single-effect evaporator is made of graphite.

[0014] The characteristics of the utility model's system for purifying and recovering high-concentration industrial phosphoric acid from waste phosphoric acid in the electronics industry are:

[0015] 1. Use inorganic ultrafiltration and nanofiltration devices to achieve preliminary removal of impurities in waste phosphoric acid without introducing new substances or causing secondary pollution; use membrane distillation devices to concentrate and purify waste phosphoric acid; and use single-effect evaporators to further concentrate to obtain high-concentration industrial phosphoric acid;

[0016] 2. Maximize the use of wastewater and waste heat to achieve resource recycling, save energy and reduce costs;

[0017] 3. The treatment process of this system is simple to operate. The introduction of membrane distillation technology and single-effect evaporation combined technology can effectively separate pollutants while concentrating and recovering phosphoric acid. It has the advantages of low energy consumption, flexible operation and high efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the principle structure of a system for purifying waste phosphoric acid in the electronics industry and recovering high-concentration industrial phosphoric acid. DETAILED DESCRIPTION

[0019] The present invention will be further described below with reference to the accompanying drawings.

[0020] See also Figure 1 The utility model discloses a system for purifying and recovering high-concentration industrial phosphoric acid from waste phosphoric acid in the electronics industry, comprising a phosphoric acid dilution tank 2, an inorganic ultrafiltration device 3, a nanofiltration device 4, a membrane distillation device 5, a single-effect evaporator 6, and a condensed water tank 7; wherein,

[0021] The inlet of the phosphoric acid dilution tank 2 is connected to the outlet of the waste phosphoric acid storage tank 1;

[0022] The inlet of the inorganic ultrafiltration device 3 is connected to the outlet of the phosphoric acid dilution tank 2;

[0023] The feed liquid inlet of the nanofiltration device 4 is connected to the outlet of the inorganic ultrafiltration device 3; the retentate of the nanofiltration device 4 is refluxed into the phosphoric acid dilution tank 2 through the circulation mechanism;

[0024] The inlet of the membrane distillation device 5 is connected to the permeate outlet of the nanofiltration device 4;

[0025] The inlet of the single-effect evaporator 6 is connected to the outlet of the membrane distillation device 5, and the outlet of the single-effect evaporator 6 is connected to the high-concentration phosphoric acid storage tank 7; the single-effect evaporator 6 is made of graphite;

[0026] The membrane distillation unit 5 and the single-effect evaporator 6 are both heated by waste heat from the factory;

[0027] The inlet of the condensed water tank 8 is connected to the distilled water outlet of the membrane distillation device 5 and the condensed water outlet of the single-effect evaporator 6 respectively, and the outlet of the condensed water tank 8 is connected to the water supply port of the dilution tank 2.

[0028] The working process of the system for purifying and recovering high-concentration industrial phosphoric acid from waste phosphoric acid in the electronics industry of this utility model is as follows:

[0029] S1. The waste phosphoric acid solution first enters the phosphoric acid dilution tank 2 and is diluted with water to a concentration of 10-15%. It then enters the inorganic ultrafiltration device 3 and the nanofiltration device 4 for filtration. The inorganic ultrafiltration device 3 intercepts colloids, macromolecules and other particles in the waste phosphoric acid solution; the nanofiltration device 4 removes polyvalent inorganic ions in the waste phosphoric acid solution. The temperature of the nanofiltration device 4 does not exceed 35-40°C and the operating pressure is 3-4 MPa. The retentate of the nanofiltration device 4 is then returned to the phosphoric acid dilution tank 2 for circulation and purification.

[0030] S2. The phosphoric acid solution filtered by nanofiltration device 4 enters membrane distillation device 5 for separation and concentration. Membrane distillation device 5 utilizes waste heat from the plant to heat the membrane to 80-85°C, with a vacuum pressure of -85-90 kPa and an operating time of 45 minutes to 1 hour. The distilled water separated by membrane distillation device 5 enters condensate tank 8, is condensed to a temperature of 35-40°C, and then flows back to phosphoric acid dilution tank 2 as water replenishment for phosphoric acid dilution tank 2.

[0031] S3. The concentrated phosphoric acid solution separated by the membrane distillation unit 5 enters the single-effect evaporator 6 to further increase the concentration of the concentrated phosphoric acid solution. The single-effect evaporator 6 is heated by the waste heat of the factory and the temperature is controlled at 60-110°C. The high-concentration phosphoric acid obtained by the single-effect evaporator 6 enters the high-concentration phosphoric acid storage tank 7. The concentrated density of the high-concentration phosphoric acid is not less than 1.575g / cm 3, that is, the concentration of the high-concentration phosphoric acid solution is 75%, which meets the "Industrial Phosphoric Acid Standard" GB / T2091-2008 standard; the condensed water of the single-effect evaporator 6 enters the condensed water tank 8 and is condensed to a temperature of 35-40°C, and then flows back to the phosphoric acid dilution tank 2 to be used as water for the phosphoric acid dilution tank 2.

[0032] The utility model discloses a system for purifying and recovering high-concentration industrial phosphoric acid from waste phosphoric acid in the electronics industry. The inorganic ultrafiltration device 3 intercepts colloids, macromolecules and other particles in the waste phosphoric acid, significantly reducing the degree of contamination of the nanofiltration device 4, extending the cleaning cycle of the nanofiltration device 4, and extending the service life of the nanofiltration device 4, thereby reducing the overall operating cost of the system. The nanofiltration device 4 uses a special membrane component developed specifically for acid recovery, which has a better acid environment, high efficiency and stability. Compared with the multi-effect evaporator 6, the feed temperature of the membrane distillation device 5 is relatively low, and cheap low-grade energy such as factory waste heat can be utilized to reduce operating costs. The membrane distillation device 5 has a relatively simple structure and is more convenient to operate. In addition, the membrane distillation device 5 has a higher separation efficiency and can better achieve the purification and separation of the target components.

[0033] The high-concentration industrial phosphoric acid recovery system for purifying waste phosphoric acid from the electronics industry of the utility model can produce industrial phosphoric acid with large market demand and high utilization value. It is widely used in multiple industries, such as chemical raw materials, electroplating, and building materials, and plays an important supporting role in modern industry.

[0034] The above embodiments are only used to illustrate the present invention, rather than to limit the present invention. Those skilled in the art may make various changes or modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions should also fall within the scope of the present invention and should be defined by the claims.

Claims

1. A system for purifying and recovering high-concentration industrial phosphoric acid from waste phosphoric acid in the electronics industry, comprising a phosphoric acid dilution tank, an inorganic ultrafiltration device, a nanofiltration device, a membrane distillation device, a single-effect evaporator, and a condensed water tank; characterized in that: The inlet of the phosphoric acid dilution tank is connected to the outlet of the waste phosphoric acid storage tank; The inlet of the inorganic ultrafiltration device is connected to the outlet of the phosphoric acid dilution tank; The feed liquid inlet of the nanofiltration device is connected to the outlet of the inorganic ultrafiltration device, and the retentate of the nanofiltration device is refluxed into the phosphoric acid dilution tank; The inlet of the membrane distillation device is connected to the permeate outlet of the nanofiltration device; The inlet of the single-effect evaporator is connected to the outlet of the membrane distillation device, and the outlet of the single-effect evaporator is connected to the high-concentration phosphoric acid storage tank; The inlet of the condensed water tank is connected to the distilled water outlet of the membrane distillation device and the condensed water outlet of the single-effect evaporator respectively, and the outlet of the condensed water tank is connected to the water supply port of the phosphoric acid dilution tank.

2. The system for purifying and recovering high-concentration industrial phosphoric acid from waste phosphoric acid in the electronics industry according to claim 1, characterized in that: The membrane distillation device and the single-effect evaporator are both heated by waste heat from the factory.

3. The system for purifying and recovering high-concentration industrial phosphoric acid from waste phosphoric acid in the electronics industry according to claim 1, characterized in that: The single-effect evaporator is made of graphite.

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