Method for improving proportion of water-soluble phosphorus in production of 58% powdery monoammonium phosphate from middle-low-grade phosphate ore

Abstract

A method for increasing the proportion of water-soluble phosphorus in 58% powdery monoammonium phosphate produced from medium-low-grade phosphate ore comprises the steps that S1, part of slurry obtained by reacting ore pulp produced from the medium-low-grade phosphate ore with ammonia is taken and pumped into an ammoniation aging tank through an ammoniation reactor to be settled, and the settled upper-layer slurry is pumped into a plate-and-frame filter press to be subjected to slag-liquid separation; s2, the separated clear liquid is blended and pumped into the other part of the remaining slurry to be mixed, and then a qualified 58% powdery monoammonium phosphate product is obtained through concentration and drying. The impurity content in the neutralized slurry is reduced through sedimentation of the ammoniation aging tank and filter pressing of the plate-and-frame filter press, it is ensured that the proportion of water-soluble phosphorus in the produced 58% powdery monoammonium phosphate product is increased, the 80% qualified standard is achieved, and the market requirement is met. A sustainable new thought is provided for producing qualified monoammonium phosphate products from medium-low-grade directly-ground ore, the utilization rate of medium-low-grade phosphate ore is increased, the production cost of powdery monoammonium phosphate is greatly reduced, and the market competitiveness is enhanced.

Description

Technical Field

[0001] The invention relates to the technical field of 58% powdered monoammonium phosphate production, and in particular to a method for increasing the proportion of water-soluble phosphorus in 58% powdered monoammonium phosphate produced from medium- and low-grade phosphate ore. Background Art

[0002] According to the requirements of GB10205-2009, the 58% powdered monoammonium phosphate is produced by slurry concentration method using medium and low grade phosphate ore with high magnesium, iron and aluminum content as raw materials, and the percentage of water-soluble phosphorus in effective phosphorus is required to reach 80% or more. In actual production, medium and low grade direct grinding ore is used to produce 58% powdered monoammonium phosphate. Due to the high impurity content of the ore, the proportion of water-soluble phosphorus in the monoammonium phosphate product is difficult to reach the national standard of 80%, resulting in a low product qualification rate and cannot meet the national standard requirements for sale to the market. Summary of the invention

[0003] The purpose of the present invention is to provide a process research method for increasing the proportion of water-soluble phosphorus in powdered monoammonium phosphate by 58% in view of the unqualified proportion of water-soluble phosphorus in the production of monoammonium phosphate from medium and low-grade phosphate ore in chemical enterprises.

[0004] A method for increasing the proportion of water-soluble phosphorus in producing 58% powdered monoammonium phosphate from medium- and low-grade phosphate ore comprises the following steps: S1. Part of the slurry obtained by reacting the slurry produced by the medium- and low-grade phosphate ore with ammonia is pumped into the ammoniation aging tank through the ammoniation reactor for sedimentation, and the upper slurry liquid after sedimentation is pumped into the plate and frame filter press for slag-liquid separation; S2. The separated clear liquid is blended and added into the remaining slurry, and then concentrated and dried to obtain a qualified 58% powdered monoammonium phosphate product.

[0005] Preferably, the slurry produced from medium and low grade phosphate ore is a phosphoric acid solution with an acid concentration of 19.0%-20.5% prepared by a dihydrate wet phosphoric acid process.

[0006] Preferably, a portion of the slurry in S1 is pumped into an ammoniation aging tank for sedimentation through an ammoniation reactor, and the proportion of this portion is 40%-50% of the total volume of the slurry.

[0007] Preferably, the medium-low grade phosphate ore in S1 is a directly ground phosphate ore with an average pulp phosphorus content of less than 26%.

[0008] Preferably, the specific steps of concentration and drying in S2 are: the mixed slurry after blending is concentrated by II-effect and I-effect evaporators and then sent to the top of the spray tower by a high-pressure pump for atomization and drying.

[0009] Preferably, the concentration process index is based on an effective density of 1.56-1.58 g / cm 3, the first-effect neutralization degree is controlled in the range of 1.01-1.02.

[0010] Preferably, in S1, an ammoniation aging tank, a plate and frame filter press and a clear liquid storage tank are newly added on the basis of the original 58% powdered monoammonium phosphate production system device.

[0011] Preferably, in S1, the slurry obtained by reacting the slurry produced from medium and low grade phosphate ore with ammonia is controlled according to the feed flow rate of gas ammonia at 2450-3034 Nm³ / h and the feed flow rate of phosphoric acid solution at 34-42 m³ / h.

[0012] Advantages of the present invention: Effectively utilize the sedimentation of the ammoniation aging tank and the plate and frame filter press to reduce the impurity content in the neutralized slurry, ensure that the water-soluble phosphorus content of the 58% powdered monoammonium phosphate product produced is increased, and reach the 80% qualified standard to meet market requirements. Provide a new idea for sustainable operation for the production of qualified monoammonium phosphate products from medium and low-grade direct grinding ores, improve the utilization rate of medium and low-grade phosphate ores, greatly reduce the production cost of powdered monoammonium phosphate, and enhance market competitiveness. DETAILED DESCRIPTION

[0013] <Specific Example 1> 1. The wet phosphoric acid solution with an acid concentration of 19% obtained by grinding phosphate ore with an average pulp phosphorus content of less than 26% and the gas ammonia sent from the ammonia station enter the ammonia reactor for neutralization reaction. The feed flow rate of gas ammonia is 2450Nm³ / h and the feed flow rate of wet phosphoric acid solution is 34m³ / h.

[0014] 2. 40% of the total volume of the ammoniation reaction slurry is pumped into the ammoniation aging tank for sedimentation. The slurry after sedimentation in the ammoniation aging tank is pumped into the plate and frame filter press for residue-liquid separation. The separated clear liquid is sent to the clear liquid storage tank. The clear liquid from the clear liquid storage tank is pumped into the ammoniation reactor at a rate of 10 cubic meters per hour, blended with the remaining ammoniation reaction material, and sent to the II-effect and I-effect evaporators for concentration production.

[0015] 3. The process parameters are based on an effective density of 1.56-1.58 g / cm 3 The neutralization degree of the first effect is controlled in the range of 1.01-1.02. The slurry after the reaction is concentrated by the II effect and I effect evaporators and then sent to the top of the spray tower for atomization by a high-pressure pump. The hot air from the steam heat exchanger enters from the bottom of the tower and exchanges heat with the atomized slurry in countercurrent. The qualified monoammonium phosphate is transported to the bulk warehouse by a belt.

[0016] 4. The average N content of the produced thermal fertilizer samples was 10.3%, the average P content was 47.8%, the average total nutrients was 58.1%, and the average water-soluble phosphorus content was 80.26%.

[0017] <Specific Example 2> 1. The wet phosphoric acid solution with 20% acid concentration is made from the direct grinding phosphate rock with an average pulp phosphorus content of less than 26%, and the gas ammonia sent from the ammonia station enters the ammonia reactor for neutralization reaction. The feed flow rate of gas ammonia is 2740Nm³ / h and the feed flow rate of wet phosphoric acid solution is 37m³ / h.

[0018] 2. 45% of the total volume of the amination reaction slurry is pumped into the amination aging tank for sedimentation. The slurry after sedimentation in the amination aging tank is pumped into the plate and frame filter press for residue-liquid separation. The separated clear liquid is sent to the clear liquid storage tank. The clear liquid from the clear liquid storage tank is pumped into the amination reactor at a rate of 15 cubic meters per hour, blended with the remaining amination reaction slurry, and sent to the II effect and I effect evaporators for concentration production.

[0019] 3. The process index is based on density of 1.56-1.58 g / cm 3 The neutralization degree of the first effect is controlled in the range of 1.02-1.03. The slurry after the reaction is concentrated by the II effect and I effect evaporators and then sent to the top of the spray tower for atomization by a high-pressure pump. The hot air from the steam heat exchanger enters from the bottom of the tower and exchanges heat with the atomized slurry in countercurrent. The qualified monoammonium phosphate is transported to the bulk warehouse by a belt.

[0020] 4. The average N content of the produced hot fertilizer samples was 10.8%, the average P content was 47.6%, the average total nutrients was 58.4%, and the average water-soluble phosphorus content was 81.43%.

[0021] <Specific Example 3> 1. The wet phosphoric acid solution with an acid concentration of 20.5% is obtained by grinding the phosphate rock with an average pulp phosphorus content of less than 26%, and the gas ammonia sent from the ammonia station enters the ammonia reactor for neutralization reaction. The feed flow rate of gas ammonia is 3034Nm³ / h and the feed flow rate of wet phosphoric acid solution is 42m³ / h.

[0022] 2. 50% of the total volume of the amination reaction slurry is pumped into the amination aging tank for sedimentation. The slurry after sedimentation in the amination aging tank is pumped into the plate and frame filter press for residue-liquid separation. The separated clear liquid is sent to the clear liquid storage tank. The clear liquid from the clear liquid storage tank is pumped into the amination reactor at 25 cubic meters per hour, blended with the remaining amination reaction slurry, and sent to the II effect and I effect evaporators for concentration production.

[0023] 3. The process index is based on density of 1.56-1.58 g / cm 3 The neutralization degree of the first effect is controlled in the range of 1.02-1.03. The slurry after the reaction is concentrated by the II effect and I effect evaporators and then sent to the top of the spray tower for atomization by a high-pressure pump. The hot air from the steam heat exchanger enters from the bottom of the tower and exchanges heat with the atomized slurry in countercurrent. The qualified monoammonium phosphate is transported to the bulk warehouse by a belt.

[0024] 4. The average N content of the produced hot fertilizer samples was 10.7%, the average P content was 47.9%, the average total nutrients was 58.6%, and the average water-soluble phosphorus content was 81.88%.

[0025] <Comparative Example> A process research method for increasing the water-soluble phosphorus ratio of 58% powdered monoammonium phosphate comprises the following steps: 1. The wet-process phosphoric acid solution with an acid concentration of 20.5% is obtained by grinding the phosphate rock with an average pulp phosphorus content of less than 26%, and the gas ammonia sent from the ammonia station enters the ammonia reactor for neutralization reaction. The feed flow rate of gas ammonia is 3034Nm³ / h and the feed flow rate of wet-process phosphoric acid solution is 42m³ / h.

[0026] 2. Do not mix with clear liquid.

[0027] 3. The process indicators are controlled according to the first effect density of 1.56-1.58 and the first effect neutralization degree of 1.01-1.02. The slurry after reaction is concentrated by the II effect and the I effect evaporator and then sent to the top of the spray tower by a high-pressure pump for atomization. The hot air from the steam heat exchanger enters from the bottom of the tower for countercurrent heat exchange with the atomized slurry. The qualified monoammonium phosphate is transported to the bulk warehouse by the belt.

[0028] 4. The average N content of the produced thermal fertilizer samples was 10.37%, the average P content was 46.9%, the average total nutrients was 58.27%, and the average water-soluble phosphorus content was 75.3%.

[0029] The production results of specific examples 1-3 were compared with those of the control example. After two steps of sedimentation and slag removal in the ammoniation aging tank and plate and frame filter press, the impurity content in the clear liquid can be effectively reduced. With the blending of the clear liquid obtained by treating 40%-50% of the total volume of the ammoniation reaction slurry, the production of 58% powdered monoammonium phosphate from medium and low-grade phosphate ore can achieve a qualified proportion of 80% or more of water-soluble phosphorus.

[0030]

[0031] The above implementation cases are only for illustrating the technical solutions and features of the present invention, and their purpose is to enable people familiar with the technology to implement them better. They cannot be used to limit the protection scope of the present invention. All equivalent changes or modifications made according to the spirit of the present invention are within the protection scope of the present invention, and those not described in detail are prior art.

Claims

1. A method for increasing the proportion of water-soluble phosphorus in the production of 58% powdered monoammonium phosphate from medium and low-grade phosphate ore, characterized in that: The following steps are involved: S1. Part of the slurry obtained by reacting the slurry produced by the medium- and low-grade phosphate ore with ammonia is pumped into the ammoniation aging tank through the ammoniation reactor for sedimentation, and the upper slurry liquid after sedimentation is pumped into the plate and frame filter press for slag-liquid separation; S2. The separated clear liquid is blended and added into the remaining slurry, and then concentrated and dried to obtain a qualified 58% powdered monoammonium phosphate product.

2. A method for increasing the proportion of water-soluble phosphorus in producing 58% powdered monoammonium phosphate from medium and low-grade phosphate ore according to claim 1, characterized in that: The slurry produced from medium and low grade phosphate rock is a phosphoric acid solution with an acid concentration of 19.0%-20.5% produced through the dihydrate wet phosphoric acid process.

3. The method for increasing the proportion of water-soluble phosphorus in producing 58% powdered monoammonium phosphate from medium and low-grade phosphate ore according to claim 1, characterized in that: Part of the slurry in S1 is taken through the ammoniation reactor and pumped into the ammoniation aging tank for sedimentation. The proportion of this part is 40%-50% of the total volume of the slurry.

4. The method for increasing the proportion of water-soluble phosphorus in producing 58% powdered monoammonium phosphate from medium- and low-grade phosphate ore according to claim 1, characterized in that: The medium and low grade phosphate ore in S1 is direct-grinded phosphate ore with an average pulp phosphorus content of less than 26%.

5. The method for increasing the proportion of water-soluble phosphorus in producing 58% powdered monoammonium phosphate from medium- and low-grade phosphate ore according to claim 1, characterized in that: The specific steps of concentration and drying in S2 are as follows: the mixed slurry after blending is concentrated by II-effect and I-effect evaporators and then sent to the top of the spray tower by a high-pressure pump for atomization and drying.

6. A method for increasing the proportion of water-soluble phosphorus in producing 58% powdered monoammonium phosphate from medium- and low-grade phosphate ore according to claim 5, characterized in that: The concentration process index is based on the effective density of 1.56-1.58g / cm 3 , the first-effect neutralization degree is controlled in the range of 1.01-1.

02.

7. The method for increasing the proportion of water-soluble phosphorus in producing 58% powdered monoammonium phosphate from medium- and low-grade phosphate ore according to claim 1, characterized in that: In S1, based on the original 58% powdered monoammonium phosphate production system, an ammonia aging tank, a plate and frame filter press and a clear liquid storage tank are newly added.

8. The method for increasing the proportion of water-soluble phosphorus in producing 58% powdered monoammonium phosphate from medium- and low-grade phosphate ore according to claim 2, characterized in that: The slurry produced by the medium and low grade phosphate ore in S1 reacts with ammonia to obtain the slurry, which is controlled according to the feed flow rate of gas ammonia 2450-3034Nm³ / h and the feed flow rate of phosphoric acid solution 34-42m³ / h.

Images