A system and method for post-treatment of ion exchange purification of phosphoric acid

Abstract

The present invention discloses a system and method for post-processing phosphate purification by ion exchange. In this system, the bottom outlet of a calcium sulfate crystallization tank is connected to the feed end of a calcium sulfate filter, the side outlet of the calcium sulfate crystallization tank is connected to the top inlet B of a magnesium sulfate crystallization tank, and the bottom outlet of the magnesium sulfate crystallization tank is connected to the feed end of a magnesium sulfate filter. Calcium sulfate from the calcium and magnesium washing solution of the ion exchange phosphate purification system is crystallized in the calcium sulfate crystallization tank. The calcium sulfate crystals in the calcium sulfate crystallization tank are filtered and separated by a calcium sulfate filter. The solution in the calcium sulfate crystallization tank is crystallized in a magnesium sulfate crystallization tank. The magnesium sulfate crystals are filtered and separated by a magnesium sulfate filter. Using the above system and method, industrial salts such as calcium sulfate and magnesium sulfate are recovered to remove the boundary area. The recovered dilute sulfuric acid is used in a deionized exchange phosphate purification system and in a deionized exchange phosphate purification resin regeneration system. This patent aims to save energy and reduce consumption, reduce carbon emissions from production equipment, and reduce operating and maintenance costs.

Description

Technical Field

[0001] The present invention relates to the field of chemical industry, and in particular to a system and method for post-processing ion exchange purified phosphoric acid. Specifically, the invention relates to a new process for treating calcium and magnesium washing liquid from an ion exchange purified phosphoric acid system by utilizing crystallization, filtration, and separation, recovering industrial salts such as calcium sulfate and magnesium sulfate to remove boundary areas, recovering dilute sulfuric acid for use in an ion exchange purified phosphoric acid system, and recovering sulfuric acid for use in an ion exchange purified phosphoric acid resin regeneration system. Background Art

[0002] Phosphoric acid is an important intermediate chemical product with two broad applications: fertilizer production and industrial phosphate production. Wet-process phosphoric acid, produced by acid decomposing phosphate rock, is primarily used in fertilizer production due to its high impurity content. Beyond fertilizer production, wet-process phosphoric acid is difficult to widely use in other industrial sectors, and thermal phosphoric acid is typically used in these applications. Compared to wet-process phosphoric acid, thermal phosphoric acid is energy-intensive and highly polluting. Purification of wet-process phosphoric acid is essential for producing high-quality phosphates.

[0003] Ion exchange purification of phosphoric acid is a type of phosphoric acid purification system and method, which is mainly divided into three parts: ion exchange purification of phosphoric acid, ion exchange purification of phosphoric acid resin regeneration, and ion exchange purification of phosphoric acid post-treatment. Ion exchange purification of phosphoric acid post-treatment mainly includes two process steps: calcium sulfate dilute sulfuric acid recovery and magnesium sulfate sulfuric acid recovery. It is characterized by simple process, less equipment, low installed power, and no steam consumption. Summary of the Invention

[0004] The present invention aims to provide a system and method for post-processing phosphate purification by ion exchange. The system comprises a calcium sulfate crystallization tank, a calcium sulfate filter, a calcium sulfate conveyor, a magnesium sulfate crystallization tank, a magnesium sulfate circulation pump, a magnesium sulfate cooler, a magnesium sulfate filter, a magnesium sulfate conveyor, and the like. Calcium and magnesium washing solution from the ion exchange phosphate purification system enters the calcium sulfate crystallization tank through inlet A at the top of the calcium sulfate crystallization tank. Dilute sulfuric acid from the ion exchange phosphate resin regeneration system enters the calcium sulfate crystallization tank through inlet B at the top of the calcium sulfate crystallization tank. Calcium sulfate crystallizes in the calcium sulfate crystallization tank. The calcium sulfate crystals at the bottom of the calcium sulfate crystallization tank are then fed from the bottom outlet of the calcium sulfate crystallization tank to the feed end of the calcium sulfate filter using a rake. The solid calcium sulfate crystals filtered by the calcium sulfate filter are transported from the solid discharge end of the calcium sulfate filter to the feed end of the calcium sulfate conveyor, where they are then transported to the boundary area. The liquid dilute sulfuric acid filtered by the calcium sulfate filter enters the dilute sulfuric acid storage tank from the liquid discharge end of the calcium sulfate filter via the top inlet. The dilute sulfuric acid in the dilute sulfuric acid storage tank is pumped from the bottom outlet of the dilute sulfuric acid storage tank to the deionization and phosphoric acid purification system. The magnesium-containing solution in the upper portion of the calcium sulfate crystallization tank enters the magnesium sulfate crystallization tank from the side outlet of the calcium sulfate crystallization tank via the top inlet B of the magnesium sulfate crystallization tank. Concentrated sulfuric acid from the boundary area enters the magnesium sulfate crystallization tank from the top inlet A of the magnesium sulfate crystallization tank. The solution in the magnesium sulfate crystallization tank enters the magnesium sulfate cooler from the lower side outlet of the magnesium sulfate crystallization tank via the magnesium sulfate circulation pump for cooling before returning to the magnesium sulfate crystallization tank through the upper side inlet of the magnesium sulfate crystallization tank. Magnesium sulfate crystals crystallize in the magnesium sulfate crystallization tank, and a magnesium sulfate crystallization tank rake is used to transport the magnesium sulfate crystals at the bottom of the magnesium sulfate crystallization tank from the bottom outlet to the feed end of the magnesium sulfate filter. The solid magnesium sulfate crystals filtered out by the magnesium sulfate filter are sent from the solid discharge end of the magnesium sulfate filter to the feed end of the magnesium sulfate conveyor, and the magnesium sulfate conveyor sends the magnesium sulfate crystals to the boundary area; the liquid sulfuric acid filtered out by the magnesium sulfate filter enters the sulfuric acid storage tank from the liquid discharge end of the magnesium sulfate filter through the top inlet of the sulfuric acid storage tank, and the sulfuric acid in the sulfuric acid storage tank is sent from the lower outlet of the sulfuric acid storage tank by the sulfuric acid pump to the ion exchange purification phosphoric acid resin regeneration system for use.

[0005] The above system and method are used to recover industrial salts such as calcium sulfate and magnesium sulfate, remove delimited areas, and recover dilute sulfuric acid for use in deionization and purification of phosphoric acid systems, as well as in phosphoric acid resin regeneration systems. This patent aims to reduce energy consumption, lower carbon emissions from production equipment, and reduce operating and maintenance costs.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] The invention discloses an ion exchange purification phosphoric acid post-processing system. The system comprises a calcium sulfate crystallization tank, a calcium sulfate filter, a calcium sulfate conveyor, a magnesium sulfate crystallization tank, a magnesium sulfate circulation pump, a magnesium sulfate cooler, the magnesium sulfate filter, the magnesium sulfate conveyor, etc. The top inlet A of the calcium sulfate crystallization tank is connected to a calcium and magnesium washing liquid pipeline from an ion exchange purification phosphoric acid system, the top inlet B of the calcium sulfate crystallization tank is connected to a dilute sulfuric acid pipeline from an ion exchange purification phosphoric acid resin regeneration system, the bottom outlet of the calcium sulfate crystallization tank is connected to a feed end of the calcium sulfate filter, the side outlet of the calcium sulfate crystallization tank is connected to the top inlet B of the magnesium sulfate crystallization tank, the top inlet A of the magnesium sulfate crystallization tank is connected to a concentrated sulfuric acid pipeline from a boundary zone, the bottom outlet of the magnesium sulfate crystallization tank is connected to the feed end of the magnesium sulfate filter, the side lower outlet of the magnesium sulfate crystallization tank is connected to the side upper inlet of the magnesium sulfate crystallization tank via the magnesium sulfate circulation pump and the magnesium sulfate cooler, the side upper inlet of the magnesium sulfate cooler is connected to a cooling water supply pipeline from the boundary zone, and the side lower outlet of the magnesium sulfate cooler is connected to a cooling return water pipeline from the deboundary zone.

[0008] In the above system: the solid discharge end of the calcium sulfate filter is connected to the feed end of the calcium sulfate conveyor, and the discharge end of the calcium sulfate conveyor is demarcated; the liquid discharge end of the calcium sulfate filter is connected to the top inlet of the dilute sulfuric acid storage tank, and the lower outlet of the dilute sulfuric acid storage tank is connected to the dilute sulfuric acid pipeline of the deionized exchange phosphoric acid purification system through a dilute sulfuric acid pump.

[0009] In the above system: the solid discharge end of the magnesium sulfate filter is connected to the feed end of the magnesium sulfate conveyor, and the discharge end of the magnesium sulfate conveyor is delimited; the liquid discharge end of the magnesium sulfate filter is connected to the top inlet of the sulfuric acid storage tank, and the lower outlet of the sulfuric acid storage tank is connected to the sulfuric acid pipeline of the deionized exchange purification phosphoric acid resin regeneration system through a sulfuric acid pump.

[0010] In the above system: the calcium sulfate crystallization tank is provided with a calcium sulfate crystallization tank rake machine, and the magnesium sulfate crystallization tank is provided with a magnesium sulfate crystallization tank rake machine.

[0011] A production method for post-processing phosphoric acid purification by ion exchange using the above system comprises the following steps, wherein more than one substance can be recovered:

[0012] (1) Calcium sulfate and dilute sulfuric acid recovery section: The calcium and magnesium washing solution from the ion exchange phosphoric acid purification system enters the calcium sulfate crystallization tank from the top inlet A of the calcium sulfate crystallization tank. The dilute sulfuric acid from the ion exchange phosphoric acid resin regeneration system enters the calcium sulfate crystallization tank from the top inlet B of the calcium sulfate crystallization tank. Calcium sulfate crystallizes in the calcium sulfate crystallization tank. The calcium sulfate crystals at the bottom of the calcium sulfate crystallization tank are sent from the bottom outlet of the calcium sulfate crystallization tank to the feed end of the calcium sulfate filter by a calcium sulfate crystallization tank rake. The solid calcium sulfate crystals filtered out by the calcium sulfate filter are sent to the feed end of the calcium sulfate conveyor from the solid discharge end of the calcium sulfate filter. The calcium sulfate conveyor sends the calcium sulfate crystals to the boundary area. The liquid dilute sulfuric acid filtered out by the calcium sulfate filter enters the dilute sulfuric acid storage tank from the liquid discharge end of the calcium sulfate filter through the top inlet of the dilute sulfuric acid storage tank. The dilute sulfuric acid in the dilute sulfuric acid storage tank is sent from the lower outlet of the dilute sulfuric acid storage tank by a dilute sulfuric acid pump to the ion exchange phosphoric acid purification system for use. The magnesium-containing solution at the top of the calcium sulfate crystallization tank is sent to the magnesium sulfate and sulfuric acid recovery section from the side outlet of the calcium sulfate crystallization tank.

[0013] (2) Magnesium sulfate and sulfuric acid recovery section: The magnesium-containing solution from the calcium sulfate and dilute sulfuric acid recovery section enters the magnesium sulfate crystallization tank from the inlet B at the top of the magnesium sulfate crystallization tank, and the concentrated sulfuric acid from the boundary zone enters the magnesium sulfate crystallization tank from the inlet A at the top of the magnesium sulfate crystallization tank. The solution in the magnesium sulfate crystallization tank enters the magnesium sulfate cooler from the lower outlet of the magnesium sulfate crystallization tank through the magnesium sulfate circulation pump for cooling, and then returns to the magnesium sulfate crystallization tank through the upper inlet of the magnesium sulfate crystallization tank. Magnesium sulfate crystallizes in the magnesium sulfate crystallization tank, and the magnesium sulfate crystals at the bottom of the magnesium sulfate crystallization tank are sent from the bottom outlet of the magnesium sulfate crystallization tank to the feed end of the magnesium sulfate filter by the magnesium sulfate crystallization tank rake. The solid magnesium sulfate crystals filtered out by the magnesium sulfate filter are sent from the solid discharge end of the magnesium sulfate filter to the feed end of the magnesium sulfate conveyor, and the magnesium sulfate conveyor sends the magnesium sulfate crystals to the boundary zone; the liquid sulfuric acid filtered out by the magnesium sulfate filter enters the sulfuric acid storage tank from the liquid discharge end of the magnesium sulfate filter through the top inlet of the sulfuric acid storage tank, and the sulfuric acid in the sulfuric acid storage tank is sent from the lower outlet of the sulfuric acid storage tank by the sulfuric acid pump to the ion exchange purification phosphoric acid resin regeneration system for use.

[0014] A method for post-processing phosphoric acid purification by ion exchange includes crystallization, filtration, and separation of a calcium-magnesium washing solution; cooling, crystallization, filtration, and separation of a magnesium-containing solution; and recovery of calcium sulfate, magnesium sulfate, dilute sulfuric acid, and sulfuric acid. The method is characterized in that the production process includes a calcium sulfate and dilute sulfuric acid recovery section and a magnesium sulfate and sulfuric acid recovery section. The steps are as follows. More than one substance can be recovered. Calcium sulfate, magnesium sulfate, dilute sulfuric acid, and sulfuric acid are used as examples:

[0015] (1) Calcium sulfate and dilute sulfuric acid recovery section: The calcium and magnesium washing solution from the ion exchange phosphoric acid purification system enters the calcium sulfate crystallization tank from the inlet A at the top of the calcium sulfate crystallization tank. The dilute sulfuric acid H2SO4 with a mass concentration of ≤45% from the ion exchange phosphoric acid resin regeneration system enters the calcium sulfate crystallization tank from the inlet B at the top of the calcium sulfate crystallization tank. The temperature in the calcium sulfate crystallization tank is controlled at >44°C. Calcium sulfate crystallizes in the calcium sulfate crystallization tank. The calcium sulfate crystals at the bottom of the calcium sulfate crystallization tank are sent from the bottom outlet of the calcium sulfate crystallization tank to the feed end of the calcium sulfate filter using a calcium sulfate crystallization tank rake. The solid calcium sulfate crystals filtered out of the calcium sulfate filter are sent from the solid discharge end of the calcium sulfate filter to the feed end of the calcium sulfate conveyor, and the calcium sulfate conveyor sends the calcium sulfate crystals to the boundary area. The liquid dilute sulfuric acid H2SO4 with a mass concentration of ≤35% filtered out of the calcium sulfate filter enters the dilute sulfuric acid storage tank from the liquid discharge end of the calcium sulfate filter through the top inlet of the dilute sulfuric acid storage tank. The dilute sulfuric acid in the dilute sulfuric acid storage tank is sent from the lower outlet of the dilute sulfuric acid storage tank by a dilute sulfuric acid pump to the ion exchange phosphoric acid purification system for use. The magnesium-containing solution at the top of the calcium sulfate crystallization tank is exported from the side of the calcium sulfate crystallization tank to the magnesium sulfate and sulfuric acid recovery section.

[0016] (2) Magnesium sulfate and sulfuric acid recovery section: The magnesium-containing solution from the calcium sulfate and dilute sulfuric acid recovery section enters the magnesium sulfate crystallization tank from the top inlet B of the magnesium sulfate crystallization tank. The concentrated sulfuric acid H2SO4 from the boundary area with a mass concentration of ≤98% enters the magnesium sulfate crystallization tank from the top inlet A of the magnesium sulfate crystallization tank. The solution in the magnesium sulfate crystallization tank enters the magnesium sulfate cooler from the lower side outlet of the magnesium sulfate crystallization tank through the magnesium sulfate circulation pump for cooling, and then returns to the magnesium sulfate crystallization tank through the upper side inlet of the magnesium sulfate crystallization tank. The temperature in the magnesium sulfate crystallization tank is controlled at ≤44°C. Magnesium sulfate crystallizes in the magnesium sulfate crystallization tank, and the magnesium sulfate crystals at the bottom of the magnesium sulfate crystallization tank are sent to the feed end of the magnesium sulfate filter from the bottom outlet of the magnesium sulfate crystallization tank using a magnesium sulfate crystallization tank rake. The solid magnesium sulfate crystals filtered out by the magnesium sulfate filter are sent from the solid discharge end of the magnesium sulfate filter to the feed end of the magnesium sulfate conveyor, and the magnesium sulfate conveyor sends the magnesium sulfate crystals to the boundary area; the liquid sulfuric acid H2SO4 filtered out by the magnesium sulfate filter with a mass concentration of ≥73% enters the sulfuric acid storage tank from the liquid discharge end of the magnesium sulfate filter through the top inlet of the sulfuric acid storage tank, and the sulfuric acid in the sulfuric acid storage tank is sent from the lower outlet of the sulfuric acid storage tank by the sulfuric acid pump to the ion exchange purification phosphoric acid resin regeneration system for use.

[0017] Beneficial effects of the present invention:

[0018] The present invention provides a system and method for post-processing ion exchange-purified phosphoric acid. This system and method can process the calcium and magnesium wash solution from the ion exchange-purified phosphoric acid system, recovering industrial salts such as calcium sulfate and magnesium sulfate to remove delimited areas. The recovered dilute sulfuric acid can then be used in the ion exchange-purified phosphoric acid system and in the ion exchange-purified phosphoric acid resin regeneration system. This patent aims to save energy and reduce consumption, lower the production cost of ion exchange-purified phosphoric acid, reduce carbon emissions from production equipment, and reduce operating and maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is the process flow diagram of this patent

[0020] Among them, calcium sulfate crystallization tank 1, calcium sulfate crystallization tank rake 2, calcium sulfate filter 3, calcium sulfate conveyor 4, dilute sulfuric acid storage tank 5, dilute sulfuric acid pump 6, magnesium sulfate crystallization tank 7, magnesium sulfate crystallization tank rake 8, magnesium sulfate circulation pump 9, magnesium sulfate cooler 10, magnesium sulfate filter 11, magnesium sulfate conveyor 12, sulfuric acid storage tank 13, sulfuric acid pump 14. DETAILED DESCRIPTION

[0021] The present invention will be further described below with reference to the embodiments, but the protection scope of the present invention is not limited thereto:

[0022] like Figure 1 A system for post-processing of ion exchange purification of phosphoric acid, the system comprising a calcium sulfate crystallization tank 1, a calcium sulfate filter 3, a calcium sulfate conveyor 4, a magnesium sulfate crystallization tank 7, a magnesium sulfate circulation pump 9, a magnesium sulfate cooler 10, a magnesium sulfate filter 11, a magnesium sulfate conveyor 12, etc., wherein the top A inlet of the calcium sulfate crystallization tank 1 is connected to a calcium and magnesium washing liquid pipeline from an ion exchange purification phosphoric acid system, the top B inlet of the calcium sulfate crystallization tank 1 is connected to a dilute sulfuric acid pipeline from an ion exchange purification phosphoric acid resin regeneration system, and the bottom outlet of the calcium sulfate crystallization tank 1 is connected to a feed of the calcium sulfate filter 3. The end is connected, calcium sulfate crystallization tank 1 side outlet is connected to magnesium sulfate crystallization tank 7 top B import, magnesium sulfate crystallization tank 7 top A import is connected to the concentrated sulfuric acid pipeline from the boundary zone, magnesium sulfate crystallization tank 7 bottom outlet is connected to magnesium sulfate filter 11 feed ends, magnesium sulfate crystallization tank 7 side lower outlets are connected to magnesium sulfate crystallization tank 7 side upper imports by magnesium sulfate circulation pump 9, magnesium sulfate cooler 10, magnesium sulfate cooler 10 side upper imports are connected to the cooling water supply pipeline from the boundary zone, and magnesium sulfate cooler 10 side lower outlets are connected to the cooling return water pipeline of the boundary zone.

[0023] The solid discharge end of the calcium sulfate filter 3 is connected to the feed end of the calcium sulfate conveyor 4, and the discharge end of the calcium sulfate conveyor 4 is delimited; the liquid discharge end of the calcium sulfate filter 3 is connected to the top inlet of the dilute sulfuric acid storage tank 5, and the lower outlet of the dilute sulfuric acid storage tank 5 is connected to the dilute sulfuric acid pipeline of the deionized exchange phosphoric acid purification system through a dilute sulfuric acid pump 6.

[0024] The solid discharge end of the magnesium sulfate filter 11 is connected to the feed end of the magnesium sulfate conveyor 12, and the discharge end of the magnesium sulfate conveyor 12 is delimited; the liquid discharge end of the magnesium sulfate filter 11 is connected to the top inlet of the sulfuric acid storage tank 13, and the lower outlet of the sulfuric acid storage tank 13 is connected to the sulfuric acid pipeline of the deionized exchange purification phosphoric acid resin regeneration system through the sulfuric acid pump 14.

[0025] The calcium sulfate crystallization tank 1 is provided with a calcium sulfate crystallization tank rake 2 , and the magnesium sulfate crystallization tank 7 is provided with a magnesium sulfate crystallization tank rake 8 .

[0026] The production method for post-treatment of phosphoric acid by ion exchange purification using the above system includes the following steps. More than one substance can be recovered. Calcium sulfate, magnesium sulfate, dilute sulfuric acid, and sulfuric acid are used as examples:

[0027] (1) Calcium sulfate and dilute sulfuric acid recovery section: The calcium and magnesium washing solution from the ion exchange purification phosphoric acid system enters the calcium sulfate crystallization tank 1 from the top inlet A of the calcium sulfate crystallization tank 1. The dilute sulfuric acid H2SO4 with a mass concentration of 42% from the ion exchange purification phosphoric acid resin regeneration system enters the calcium sulfate crystallization tank 1 from the top inlet B of the calcium sulfate crystallization tank 1. The temperature in the calcium sulfate crystallization tank is controlled at >44°C. Calcium sulfate crystallizes in the calcium sulfate crystallization tank 1. The calcium sulfate crystals at the bottom of the calcium sulfate crystallization tank 1 are fed to the feed end of the calcium sulfate filter 3 from the bottom outlet of the calcium sulfate crystallization tank 1 by the calcium sulfate crystallization tank rake 2. The solid calcium sulfate crystals filtered by calcium sulfate filter 3 are transported from the solid discharge end of calcium sulfate filter 3 to the feed end of calcium sulfate conveyor 4, which then transports the calcium sulfate crystals to the boundary area. Liquid dilute sulfuric acid (H2SO4) with a mass concentration of 30% is then transported from the liquid discharge end of calcium sulfate filter 3 through the top inlet of dilute sulfuric acid storage tank 5. The dilute sulfuric acid in dilute sulfuric acid storage tank 5 is then transported from the bottom outlet of dilute sulfuric acid storage tank 5 by dilute sulfuric acid pump 6 to the ion exchange phosphoric acid purification system for use. The magnesium-containing solution in the upper portion of calcium sulfate crystallization tank 1 is then transported from the side outlet of calcium sulfate crystallization tank 1 to the magnesium sulfate and sulfuric acid recovery section.

[0028] (2) Magnesium sulfate sulfuric acid recovery section: The magnesium-containing solution from the calcium sulfate dilute sulfuric acid recovery section enters the magnesium sulfate crystallization tank 7 from the top B inlet of the magnesium sulfate crystallization tank 7. The concentrated sulfuric acid H2SO4 with a mass concentration of 93% from the boundary area enters the magnesium sulfate crystallization tank 7 from the top A inlet of the magnesium sulfate crystallization tank 7. The solution in the magnesium sulfate crystallization tank 7 enters the magnesium sulfate cooler 10 from the lower side outlet of the magnesium sulfate crystallization tank 7 through the magnesium sulfate circulation pump 9 for cooling, and then returns to the magnesium sulfate crystallization tank 7 through the upper side inlet of the magnesium sulfate crystallization tank 7. The temperature in the magnesium sulfate crystallization tank is controlled at ≤44°C. Magnesium sulfate crystallizes in the magnesium sulfate crystallization tank 7, and the magnesium sulfate crystals at the bottom of the magnesium sulfate crystallization tank 7 are sent to the feed end of the magnesium sulfate filter 11 from the bottom outlet of the magnesium sulfate crystallization tank 7 by the magnesium sulfate crystallization tank rake 8. The solid magnesium sulfate crystals filtered out by the magnesium sulfate filter 11 are sent from the solid discharge end of the magnesium sulfate filter 11 to the feed end of the magnesium sulfate conveyor 12, and the magnesium sulfate conveyor 12 sends the magnesium sulfate crystals to the boundary area; the liquid sulfuric acid H2SO4 with a mass concentration of 75% filtered out by the magnesium sulfate filter 11 is sent from the liquid discharge end of the magnesium sulfate filter 11 through the top inlet of the sulfuric acid storage tank 13 into the sulfuric acid storage tank 13, and the sulfuric acid in the sulfuric acid storage tank 13 is sent from the lower outlet of the sulfuric acid storage tank 13 by the sulfuric acid pump 14 to the ion exchange purification phosphoric acid resin regeneration system for use. The operation results of the present invention are shown in Table 1

[0029] Table 1 Performance evaluation results of 10,000 tons / year ion exchange phosphoric acid post-treatment unit

[0030] Table 1 Performance evaluation results of 10,000 tons / year ion exchange phosphoric acid post-treatment unit

[0031]

Claims

1. A system for ion exchange purification of phosphoric acid post-treatment, characterized by: The system comprises a calcium sulfate crystallization tank (1) and a calcium sulfate filter (3), wherein an inlet A at the top of the calcium sulfate crystallization tank (1) is connected to a calcium and magnesium washing liquid pipeline from an ion exchange purification phosphoric acid system, and an inlet B at the top of the calcium sulfate crystallization tank (1) is connected to a dilute sulfuric acid pipeline from an ion exchange purification phosphoric acid resin regeneration system; The bottom outlet of the calcium sulfate crystallization tank (1) is connected to the feed end of the calcium sulfate filter (3), the side outlet of the calcium sulfate crystallization tank (1) is connected to the top inlet B of the magnesium sulfate crystallization tank (7), the top inlet A of the magnesium sulfate crystallization tank (7) is connected to the concentrated sulfuric acid pipeline from the boundary area, the bottom outlet of the magnesium sulfate crystallization tank (7) is connected to the feed end of the magnesium sulfate filter (11), and the lower side outlet of the magnesium sulfate crystallization tank (7) is connected to the upper side inlet of the magnesium sulfate crystallization tank (7) through the magnesium sulfate circulation pump (9) and the magnesium sulfate cooler (10); The solid discharge end of the calcium sulfate filter (3) is connected to the feed end of the calcium sulfate conveyor (4), and the discharge end of the calcium sulfate conveyor (4) is delimited; the liquid discharge end of the calcium sulfate filter (3) is connected to the top inlet of the dilute sulfuric acid storage tank (5), and the lower outlet of the dilute sulfuric acid storage tank (5) is connected to the dilute sulfuric acid pipeline of the deionized exchange phosphoric acid purification system through a dilute sulfuric acid pump (6); The solid discharge end of the magnesium sulfate filter (11) is connected to the feed end of the magnesium sulfate conveyor (12), and the discharge end of the magnesium sulfate conveyor (12) is debounded; the liquid discharge end of the magnesium sulfate filter (11) is connected to the top inlet of the sulfuric acid storage tank (13), and the lower outlet of the sulfuric acid storage tank (13) is connected to the sulfuric acid pipeline of the deionized exchange purification phosphoric acid resin regeneration system through a sulfuric acid pump (14).

2. The system for ion exchange purification of phosphoric acid post-treatment according to claim 1, characterized in that: The calcium sulfate crystallization tank (1) is provided with a calcium sulfate crystallization tank rake (2), and the magnesium sulfate crystallization tank (7) is provided with a magnesium sulfate crystallization tank rake (8).

3. A production method for ion exchange purification of phosphoric acid post-treatment using the system according to claim 1, characterized in that: The method comprises the following steps: (1) Calcium sulfate dilute sulfuric acid recovery section: the calcium and magnesium washing solution from the ion exchange purification phosphoric acid system enters the calcium sulfate crystallization tank (1) from the top A inlet of the calcium sulfate crystallization tank (1), and the dilute sulfuric acid from the ion exchange purification phosphoric acid resin regeneration system enters the calcium sulfate crystallization tank (1) from the top B inlet of the calcium sulfate crystallization tank (1). Calcium sulfate crystallizes in the calcium sulfate crystallization tank (1), and the calcium sulfate crystals at the bottom of the calcium sulfate crystallization tank (1) are sent to the feed end of the calcium sulfate filter (3) from the bottom outlet of the calcium sulfate crystallization tank (1) by the calcium sulfate crystallization tank rake (2); the solid calcium sulfate crystals filtered out by the calcium sulfate filter (3) are filtered out. The crystals are sent from the solid discharge end of the calcium sulfate filter (3) to the feed end of the calcium sulfate conveyor (4), and the calcium sulfate conveyor (4) sends the calcium sulfate crystals to the boundary area; the liquid dilute sulfuric acid filtered out of the calcium sulfate filter (3) enters the dilute sulfuric acid storage tank (5) from the liquid discharge end of the calcium sulfate filter (3) through the top inlet of the dilute sulfuric acid storage tank (5), and the dilute sulfuric acid in the dilute sulfuric acid storage tank (5) is sent from the lower outlet of the dilute sulfuric acid storage tank (5) by the dilute sulfuric acid pump (6) to the ion exchange purification phosphoric acid system for use; the magnesium-containing solution in the upper part of the calcium sulfate crystallization tank (1) is sent from the side outlet of the calcium sulfate crystallization tank (1) to the magnesium sulfate sulfuric acid recovery section; (2) Magnesium sulfate and sulfuric acid recovery section: The magnesium-containing solution from the calcium sulfate and dilute sulfuric acid recovery section enters the magnesium sulfate crystallization tank (7) from the top inlet B of the magnesium sulfate crystallization tank (7), and the concentrated sulfuric acid from the boundary area enters the magnesium sulfate crystallization tank (7) from the top inlet A of the magnesium sulfate crystallization tank (7). The solution in the magnesium sulfate crystallization tank (7) enters the magnesium sulfate cooler (10) from the lower outlet of the side of the magnesium sulfate crystallization tank (7) through the magnesium sulfate circulation pump (9) for cooling, and then returns to the magnesium sulfate crystallization tank (7) through the upper inlet of the side of the magnesium sulfate crystallization tank (7); magnesium sulfate crystallizes in the magnesium sulfate crystallization tank (7), and the magnesium sulfate crystallization tank rake (8) is used to remove the magnesium sulfate crystallization tank (7) from the bottom of the magnesium sulfate crystallization tank (7). The magnesium sulfate crystals are fed from the bottom outlet of the magnesium sulfate crystallization tank (7) to the feed end of the magnesium sulfate filter (11); the solid magnesium sulfate crystals filtered out by the magnesium sulfate filter (11) are fed from the solid discharge end of the magnesium sulfate filter (11) to the feed end of the magnesium sulfate conveyor (12), and the magnesium sulfate conveyor (12) transports the magnesium sulfate crystals to the boundary area; the liquid sulfuric acid filtered out by the magnesium sulfate filter (11) enters the sulfuric acid storage tank (13) from the liquid discharge end of the magnesium sulfate filter (11) through the top inlet of the sulfuric acid storage tank (13), and the sulfuric acid in the sulfuric acid storage tank (13) is fed from the lower outlet of the sulfuric acid storage tank (13) by the sulfuric acid pump (14) to the ion exchange purification phosphoric acid resin regeneration system for use.

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