Device for purifying raffinate acid by using ammonium phosphate slag slurry

Abstract

The utility model provides a device for purifying raffinate acid by using ammonium phosphate slag slurry, which comprises a high-shear reactor, an aging tank and a filter press, the high shear force of the high-shear reactor is used for quickly mixing and promoting chemical reaction, and the high-shear reactor, the aging tank and the filter press are specially connected in series. And the whole process from impurity removal to resource recovery is efficiently and continuously carried out.

Description

Technical Field

[0001] The utility model relates to the field of chemical equipment, in particular to a device for purifying raffinate. Background Art

[0002] In the production of wet phosphoric acid, the purification of phosphoric acid by solvent extraction can generally achieve a purification rate of 55% to 60%. The raffinate acid generated in this process contains 40% to 45% of crude phosphoric acid that has not been purified. This part of phosphoric acid is rich in impurity ions. Since these impurity ions hardly react with the extractant during the extraction process, they are almost all left in the raffinate acid, resulting in an increase in the viscosity of the raffinate acid, which poses a great challenge to its recovery and reuse.

[0003] The traditional method of treating raffinate is to return it to the phosphate compound fertilizer system and mix it with wet-process phosphoric acid. The mixed acid is then used to produce fertilizer-grade ammonium phosphate by reducing the concentration of impurity ions in the mixed acid to an acceptable level. Although this method can produce fertilizers that meet national standards, it consumes a large amount of new-process phosphoric acid, and the final product has a low water solubility and a large output.

[0004] With the rapid development of wet phosphoric acid purification technology and the continuous growth of raffinate production, the continued use of traditional treatment methods will produce a large amount of low-quality fertilizers, which will not only increase production costs, but also pose a threat to the sustainable development of the phosphorus chemical industry. Therefore, it is urgent to innovate the treatment and utilization of raffinate and develop new technologies and methods to improve resource utilization efficiency and environmental friendliness to meet the development needs of the industry. Utility Model Content

[0005] The utility model relates to a device for raffinate acid purification, which is mainly used for improving the processing efficiency of ammonium phosphate slurry and raffinate acid and optimizing resource recovery.

[0006] A device for purifying residual acid with ammonium phosphate slurry comprises a high shear reactor, wherein a high shear agitator is arranged inside the high shear reactor; the high shear reactor is connected to an aging tank via a mixed slurry outlet pipe, a lower slurry outlet pipe is arranged at the rear end of the aging tank, a filter press is connected to the end of the lower slurry outlet pipe, and a reflux pipe is connected to the aging tank above the filter press.

[0007] Furthermore, a raffinate acid feed pipe is connected above the high shear reactor; and the high shear agitator is connected to a phosphate ammonium slurry feed pipe.

[0008] Furthermore, an upper clear liquid outlet pipe is also provided at the rear end of the aging tank.

[0009] Furthermore, a filter residue outlet is connected to the bottom of the filter press.

[0010] Furthermore, the high shear reactor used in the present device may also be replaced by other types of reactors, such as an ultrasonic reactor or a microwave-assisted reactor.

[0011] The beneficial effects of the utility model are as follows:

[0012] This device uses a high shear reactor to quickly mix and promote chemical reactions with its high shear force, mixes phosphate ammonium slurry with raffinate acid, and promotes the precipitation of metal impurities in raffinate acid by using the pH adjustment ability of the phosphate ammonium slurry and its function as a crystal nucleus. The specific series configuration of the high shear reactor, aging tank, and filter press makes the entire process from impurity removal to resource recovery efficient and continuous.

[0013] In the operation of this device, the ammonium phosphate slurry and the raffinate acid are mixed in a high shear reactor. A stirring mechanism is provided inside the reactor, and the operating temperature is maintained at 60-70°C to ensure that impurities can be effectively precipitated and form solid particles that are easy to separate. Through this high shear mixing method, the reaction residence time, which originally required 1-2 hours, is greatly shortened to only 10-20 minutes.

[0014] The mixture is transferred to an aging tank, where the solid particles are allowed to settle further to form distinct layers. The upper clear liquid has a metal impurity content comparable to that of wet-process phosphoric acid and can be used to produce high-nutrient, high-water-soluble phosphate fertilizers. The slurry in the lower layer is filtered through a filter press, and the resulting filter residue can be used to produce low-nutrient phosphate fertilizers, maximizing the use of phosphorus resources.

[0015] This technology not only achieves efficient removal of metal impurities in the raffinate acid, but also significantly reduces phosphorus loss, improving the environmental protection and economic benefits of the entire treatment process. This equipment provides an innovative solution for the phosphoric acid production and waste treatment industries, aiming to optimize the utilization of phosphorus resources and reduce environmental burden. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 : Schematic diagram of the structure of the utility model.

[0017] Explanation of the markings in the figure: 1. High shear reactor; 2. Aging tank; 3. Filter press; 4. Raffinate acid feed pipe; 5. Ammonium phosphate slurry feed pipe; 6. Mixed slurry outlet pipe; 7. Upper clear liquid outlet pipe; 8. Lower slurry outlet pipe; 9. Reflux pipe; 10. Filter residue outlet; 11. High shear agitator. DETAILED DESCRIPTION

[0018] The implementation scheme of the utility model will be described in detail below in conjunction with examples. The following examples are only used to illustrate the utility model and should not be regarded as limiting the scope of the utility model.

[0019] Example 1

[0020] A device for purifying residual acid with ammonium phosphate slurry comprises a high shear reactor 1, wherein a high shear agitator 11 is arranged inside the high shear reactor 1; the high shear reactor 1 is connected to an aging tank 2 via a mixed slurry outlet pipe 6, the rear end of the aging tank 2 is provided with two outlets, namely an upper clear liquid outlet pipe 7 and a lower slurry outlet pipe 8, the end of the lower slurry outlet pipe 8 is connected to a filter press 3, a filter residue outlet 10 is connected below the filter press 3, and a reflux pipe 9 is connected to the aging tank 2 above the filter press 3.

[0021] A raffinate acid feed pipe 4 is connected above the high shear reactor; and the high shear agitator 11 is connected to the phosphate ammonium slurry feed pipe 5.

[0022] Example 2

[0023] The device described in Example 1 is used, and the raffinate acid enters the high shear reactor 1 through the raffinate acid feed pipe 4, and the ammonium phosphate slurry enters the high shear agitator 11 through the ammonium phosphate slurry feed pipe 5, and the two are mixed under the action of the high shear agitator 11. At a temperature of 60-70°C and under the action of high shear force, the mixture reacts rapidly for 10-20 minutes, and after adjusting to an appropriate pH, it is sent to the aging tank 2 through the mixed slurry outlet pipe 6 for natural sedimentation. After sedimentation, the supernatant is discharged through the supernatant outlet pipe 7 for the production of high-nutrient diammonium phosphate; the lower slurry is discharged through the lower slurry outlet pipe 8, and then filtered by the filter press 3, and the filtrate returns to the aging tank 2 through the reflux pipe 9, and the filter residue is sent out of the device through the filter residue outlet 10 for the production of low-nutrient phosphate fertilizer.

Claims

1. A device for purifying raffinate acid using ammonium phosphate slurry, characterized in that: The invention comprises a high shear reactor (1), wherein a high shear stirrer (11) is installed inside the high shear reactor (1); the high shear reactor (1) is connected to an aging tank (2) via a mixed slurry outlet pipe (6); a lower slurry outlet pipe (8) is provided at the rear end of the aging tank (2); the lower slurry outlet pipe (8) is connected to a filter press (3); and a reflux pipe (9) is connected to the aging tank (2) above the filter press (3).

2. The device for purifying raffinate acid with ammonium phosphate slurry according to claim 1, characterized in that: The high shear reactor (1) is connected to a raffinate acid feed pipe (4) above; the high shear agitator (11) is connected to a phosphate ammonium slurry feed pipe (5).

3. The device for purifying raffinate acid with ammonium phosphate slurry according to claim 1, characterized in that: The rear end of the aging tank (2) is also provided with an upper clear liquid outlet pipe (7).

4. The device for purifying raffinate acid with ammonium phosphate slurry according to claim 1, characterized in that: The filter press (3) is connected to a filter residue outlet (10) at its bottom.

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