Process device for preparing trisodium phosphate by recycling phosphated residues

Abstract

The utility model relates to the technical field of hazardous waste recycling, in particular to a process device for preparing trisodium phosphate by recycling phosphated residues, which comprises a storage tank, a reactor, a plate-and-frame filter press, an evaporator, a gas-liquid separator, a crystallization tank, a centrifugal machine, a mother liquor storage tank and a drying box which are sequentially arranged from top to bottom, the lower end of the storage tank is connected with the upper end of the reactor, the lower end of the reactor is connected with the upper end of the plate-and-frame filter press, and a liquid outlet in the lower end of the plate-and-frame filter press is connected with the upper end of the evaporator. According to the treatment process device, solid waste phosphated residues and caustic soda serve as raw materials to prepare trisodium phosphate, the raw materials are low in price and easy to obtain, no by-product is generated, no pollution is caused to the environment, operation is easy, the high recovery value and good economic benefits are achieved, the preparation technology of trisodium phosphate is mastered through independent research and development of the device, waste is turned into wealth, and the production cost is reduced. The trisodium phosphate is prepared from the solid waste phosphated residues through resource research.

Description

Technical Field

[0001] This utility model relates to the field of hazardous waste resource utilization technology, and in particular to a process device for preparing trisodium phosphate from phosphating slag. Background Technology

[0002] Phosphating, as a metal surface treatment technology, is widely used in chemical, metallurgical, automotive, aerospace, and shipbuilding industries. However, the phosphating process inevitably generates solid waste phosphating slag, mainly composed of iron phosphate and zinc phosphate. Indiscriminate discharge of this solid waste phosphating slag will inevitably cause secondary pollution to the environment. Therefore, research on the resource utilization of solid waste phosphating slag is of paramount importance. The goal is to extract valuable phosphorus and iron from this white solid waste phosphating slag and transform it into products with high economic and social benefits.

[0003] Because phosphate rock resources are difficult to regenerate and replace, it is estimated that the world's phosphate rock resources can be mined for 100 to 200 years. With the development of the human economy, the consumption of phosphorus resources is constantly increasing, and eventually, phosphorus resources will face depletion. Therefore, the price of phosphorus compounds is also constantly rising. Considering environmental and economic benefits, processing and recovering phosphorus resources from phosphate slag is in line with the concept of sustainable development and is economically feasible. Utility Model Content

[0004] The purpose of this utility model is to provide a process device for the resource-based preparation of trisodium phosphate from phosphate slag in order to solve the above-mentioned technical defects in the prior art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A process apparatus for the resource-based preparation of trisodium phosphate from phosphate slag includes, from top to bottom, a storage tank, a reactor, a plate and frame filter press, an evaporator, a gas-liquid separator, a crystallization tank, a centrifuge, a mother liquor storage tank, and a drying chamber. The lower end of the storage tank is connected to the upper end of the reactor, the lower end of the reactor is connected to the upper end of the plate and frame filter press, the liquid outlet of the lower end of the plate and frame filter press is connected to the upper end of the evaporator, the gas outlet of the upper end of the evaporator is connected to the gas-liquid separator, the lower end of the evaporator is connected to the upper end of the crystallization tank, the lower end of the crystallization tank is connected to the inlet of the centrifuge, the solid material outlet of the centrifuge is connected to the inlet of the drying chamber, and the mother liquor outlet of the centrifuge is connected to the inlet of the mother liquor storage tank.

[0007] As a further description of the above technical solution:

[0008] The reactor is equipped with sodium hydroxide solution and recycled water dosing ports at the top. Both the sodium hydroxide solution dosing port and the recycled water dosing port are equipped with liquid flow meters. The reactor is also equipped with a stirrer and a pH meter.

[0009] As a further description of the above technical solution:

[0010] The reactor is equipped with a hot water circulation device, which, together with the outer wall of the reactor, forms a hot water circulation chamber. A hot water inlet is provided on the side wall of the hot water circulation chamber, and a hot water outlet is provided at the bottom of the hot water circulation chamber.

[0011] As a further description of the above technical solution:

[0012] The evaporator is equipped with a densitometer and a steam circulation device. The steam circulation device and the outer wall of the evaporator enclose a steam circulation chamber. A steam-water inlet is provided on the side wall of the steam circulation chamber, and a condensate outlet is provided at the bottom of the steam circulation chamber.

[0013] As a further description of the above technical solution:

[0014] The gas-liquid separator is equipped with a cooling water circulation device, which, together with the outer wall of the gas-liquid separator, forms a cooling water circulation chamber. A coolant inlet is provided on the side wall of the cooling water circulation chamber, and a coolant outlet is provided at the bottom of the cooling water circulation chamber. A condensate outlet is provided at the bottom of the gas-liquid separator, and a vacuum pump is connected to the upper part of the gas-liquid separator.

[0015] As a further description of the above technical solution:

[0016] The output end of the storage tank is provided with a first conveyor belt, and the output end of the first conveyor belt is connected to the upper part of the reactor.

[0017] As a further description of the above technical solution:

[0018] The reactor is equipped with a first pump at its output end, which is connected to a plate and frame filter press. A second pump is installed at the lower outlet of the plate and frame filter press, and its output end is connected to the upper end of an evaporator. A third pump is installed at the lower outlet of the evaporator, and its output end is connected to the upper end of a crystallization tank. A fourth pump is installed at the lower end of the crystallization tank, and its output end is connected to the upper end of a centrifuge. A fifth pump is installed at the lower end of the centrifuge outlet, and its output end is connected to the upper end of a mother liquor storage tank. A sixth pump is installed at the lower end of the mother liquor storage tank, and its output end is connected to the upper end of the reactor.

[0019] As a further description of the above technical solution:

[0020] A second conveyor belt is provided between the solid material outlet of the centrifuge and the inlet of the drying chamber.

[0021] In summary, due to the adoption of the above technical solution, the beneficial effects of this utility model are:

[0022] The processing device provided in this utility model uses solid waste phosphating slag and caustic soda as raw materials to prepare trisodium phosphate. The raw materials are cheap and readily available, no by-products are generated, there is no pollution to the environment, the operation is simple, and it has high recycling value and good economic benefits. Through independent research and development of this device, the preparation technology of trisodium phosphate has been mastered, and waste has been turned into treasure, enabling the preparation of trisodium phosphate from solid waste phosphating slag through resource utilization research. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the process flow of a phosphate slag resource utilization device for preparing trisodium phosphate according to the present invention.

[0024] Legend:

[0025] 1. Storage tank; 2. Reactor; 3. Plate and frame filter press; 4. Evaporator; 5. Gas-liquid separator; 6. Crystallization tank; 7. Centrifuge; 8. Mother liquor storage tank; 9. Drying oven; 10. Vacuum pump; 11. First conveyor belt; 12. First pump; 13. Second pump; 14. Third pump; 15. Fourth pump; 16. Fifth pump; 17. Sixth pump; 18. Second conveyor belt. Detailed Implementation

[0026] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0027] Please see Figure 1 This utility model provides a technical solution: a process device for the resource-based preparation of trisodium phosphate from phosphate slag, comprising, from top to bottom, a storage tank 1, a reactor 2, a plate and frame filter press 3, an evaporator 4, a gas-liquid separator 5, a crystallization tank 6, a centrifuge 7, a mother liquor storage tank 8, and a drying chamber 9. The lower end of the storage tank 1 is connected to the upper end of the reactor 2, the lower end of the reactor 2 is connected to the upper end of the plate and frame filter press 3, the lower end of the plate and frame filter press 3 is connected to the upper end of the evaporator 4, the upper end of the evaporator 4 is connected to the gas-liquid separator 5, the lower end of the evaporator 4 is connected to the upper end of the crystallization tank 6, the lower end of the crystallization tank 6 is connected to the inlet of the centrifuge 7, the solid material outlet of the centrifuge 7 is connected to the inlet of the drying chamber 9, and the mother liquor outlet of the centrifuge 7 is connected to the inlet of the mother liquor storage tank 8.

[0028] Specifically, such as Figure 1As shown, the upper end of reactor 2 is equipped with sodium hydroxide solution and recycled water dosing ports. Both the sodium hydroxide solution dosing port and the recycled water dosing port are equipped with liquid flow meters. Reactor 2 is also equipped with a stirring paddle and a pH meter.

[0029] The reactor 2 is equipped with a hot water circulation device, which, together with the outer wall of the reactor 2, forms a hot water circulation chamber. A hot water inlet is provided on the side wall of the hot water circulation chamber, and a hot water outlet is provided at the bottom of the hot water circulation chamber.

[0030] Specifically, such as Figure 1 As shown, the evaporator 4 is equipped with a densitometer inside and a steam circulation device. The steam circulation device and the outer wall of the evaporator 4 enclose a steam circulation chamber. A steam water inlet is provided on the side wall of the steam circulation chamber, and a condensate outlet is provided at the bottom of the steam circulation chamber.

[0031] Specifically, such as Figure 1 As shown, the gas-liquid separator 5 is equipped with a cooling water circulation device. The cooling water circulation device and the outer wall of the gas-liquid separator 5 enclose a cooling water circulation chamber. A coolant inlet is provided on the side wall of the cooling water circulation chamber, and a coolant outlet is provided at the bottom of the cooling water circulation chamber. A condensate outlet is provided at the bottom of the gas-liquid separator 5, and a vacuum pump 10 is connected to the upper part of the gas-liquid separator 5.

[0032] Specifically, such as Figure 1 As shown, a first conveyor belt 11 is provided at the output end of the storage tank 1, and the output end of the first conveyor belt 11 is connected to the upper part of the reactor 2.

[0033] Specifically, such as Figure 1 As shown, a first pump 12 is installed at the output end of reactor 2, and the output end of the first pump 12 is connected to the plate and frame filter press 3. A second pump 13 is installed at the lower outlet of the plate and frame filter press 3, and the output end of the second pump 13 is connected to the upper end of the evaporator 4. A third pump 14 is installed at the lower outlet of the evaporator 4, and the output end of the third pump 14 is connected to the upper end of the crystallization tank 6. A fourth pump 15 is installed at the lower end of the crystallization tank 6, and the output end of the fourth pump 15 is connected to the upper end of the centrifuge 7. A fifth pump 16 is installed at the lower end of the outlet of the centrifuge 7, and the output end of the fifth pump 16 is connected to the upper end of the mother liquor storage tank 8. A sixth pump 17 is installed at the lower end of the mother liquor storage tank 8, and the output end of the sixth pump 17 is connected to the upper end of reactor 2.

[0034] Specifically, such as Figure 1 As shown, a second conveyor belt 18 is provided between the solid material outlet of the centrifuge 7 and the inlet of the drying chamber 9.

[0035] Working principle: The process for preparing trisodium phosphate from phosphate slag includes the following steps:

[0036] Step 1, Preparation of trisodium phosphate: Phosphating residue and sodium hydroxide solution are added to reactor 2 through the first conveyor belt 11 and sodium hydroxide solution inlet. The reaction temperature is controlled at about 80°C by a hot water circulation device. After the reaction, recycled water is added to control the pH of the system to about 13.0. The specific reaction equation is as follows.

[0037] FePO4 + 3NaOH = Na3PO4 + Fe(OH)3↓

[0038] Zn3(PO4)2+3NaOH+H2O=Na3PO4+Zn(OH)2↓

[0039] Step 2, solid-liquid separation: The mixture after step 1 is pumped into plate and frame filter press 3 by the first pump 12. The filter residue after solid-liquid separation is collected and used for resource extraction of iron and zinc.

[0040] Step 3, Evaporation and Concentration: The liquid processed in Step 2 is pumped into Evaporator 4 through the second pump 13, and the specific gravity of the sodium phosphate solution is controlled to be about 1.22 through evaporation and concentration.

[0041] Step 4, Cooling and Crystallization: The mixture after step 3 is pumped into crystallization tank 6 by the third pump 14 for cooling and crystallization to obtain solid trisodium phosphate.

[0042] Step 5, centrifugal separation: The solid-liquid mixture from step 4 is pumped into centrifuge 7 by the fourth pump 15. The separated filter residue is sent to drying box 9 by the second conveyor belt 18. The liquid is pumped into reactor 2 by the fifth pump 16 and the sixth pump 17 to continue to react as raw material.

[0043] Step 6: Drying: Dry the solid from step 5 to obtain the product trisodium phosphate.

[0044] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A process apparatus for the resource-based preparation of trisodium phosphate from phosphate slag, characterized in that, The system includes, from top to bottom, a storage tank (1), a reactor (2), a plate and frame filter press (3), an evaporator (4), a gas-liquid separator (5), a crystallization tank (6), a centrifuge (7), a mother liquor storage tank (8), and a drying chamber (9). The lower end of the storage tank (1) is connected to the upper end of the reactor (2), the lower end of the reactor (2) is connected to the upper end of the plate and frame filter press (3), the lower end of the plate and frame filter press (3) is connected to the upper end of the evaporator (4), the upper end of the evaporator (4) is connected to the gas-liquid separator (5), the lower end of the evaporator (4) is connected to the upper end of the crystallization tank (6), the lower end of the crystallization tank (6) is connected to the inlet of the centrifuge (7), the solid material outlet of the centrifuge (7) is connected to the inlet of the drying chamber (9), and the mother liquor outlet of the centrifuge (7) is connected to the inlet of the mother liquor storage tank (8).

2. The process apparatus for preparing trisodium phosphate from phosphate slag according to claim 1, characterized in that, The upper end of the reactor (2) is provided with sodium hydroxide solution and recycled water dosing port. Both the sodium hydroxide solution dosing port and the recycled water dosing port are equipped with liquid flow meters. The reactor (2) is equipped with a stirring paddle and a pH meter.

3. The process apparatus for resource-based preparation of trisodium phosphate from phosphate slag according to claim 1 or 2, characterized in that, The reactor (2) is equipped with a hot water circulation device. The hot water circulation device and the outer wall of the reactor (2) enclose a hot water circulation chamber. A hot water inlet is provided on the side wall of the hot water circulation chamber, and a hot water outlet is provided at the bottom of the hot water circulation chamber.

4. The process apparatus for resource-based preparation of trisodium phosphate from phosphate slag according to claim 1, characterized in that, The evaporator (4) is equipped with a densitometer inside and a steam circulation device. The steam circulation device and the outer wall of the evaporator (4) form a steam circulation chamber. A steam water inlet is provided on the side wall of the steam circulation chamber and a condensate outlet is provided at the bottom of the steam circulation chamber.

5. The process apparatus for resource-based preparation of trisodium phosphate from phosphate slag according to claim 1, characterized in that, The gas-liquid separator (5) is equipped with a cooling water circulation device. The cooling water circulation device and the outer wall of the gas-liquid separator (5) form a cooling water circulation chamber. A coolant inlet is provided on the side wall of the cooling water circulation chamber. A coolant outlet is provided at the bottom of the cooling water circulation chamber. A condensate outlet is provided at the bottom of the gas-liquid separator (5). A vacuum pump (10) is connected to the upper part of the gas-liquid separator (5).

6. The process apparatus for resource-based preparation of trisodium phosphate from phosphate slag according to claim 1, characterized in that, The first conveyor belt (11) is provided at the output end of the storage tank (1), and the output end of the first conveyor belt (11) is connected to the upper part of the reactor (2).

7. The process apparatus for resource-based preparation of trisodium phosphate from phosphate slag according to claim 1, characterized in that, The reactor (2) is equipped with a first pump (12) at its output end. The output end of the first pump (12) is connected to the plate and frame filter press (3). The lower outlet of the plate and frame filter press (3) is equipped with a second pump (13). The output end of the second pump (13) is connected to the upper end of the evaporator (4). The lower outlet of the evaporator (4) is equipped with a third pump (14). The output end of the third pump (14) is connected to the upper end of the crystallization tank (6). The lower end of the crystallization tank (6) is equipped with a fourth pump (15). The output end of the fourth pump (15) is connected to the upper end of the centrifuge (7). The lower outlet of the centrifuge (7) is equipped with a fifth pump (16). The output end of the fifth pump (16) is connected to the upper end of the mother liquor storage tank (8). The lower end of the mother liquor storage tank (8) is equipped with a sixth pump (17). The output end of the sixth pump (17) is connected to the upper end of the reactor (2).

8. The process apparatus for resource-based preparation of trisodium phosphate from phosphate slag according to claim 1, characterized in that, A second conveyor belt (18) is provided between the solid material outlet of the centrifuge (7) and the inlet of the drying box (9).

Images