阅读说明：本技术 一种饲料级磷酸钙盐生产系统及方法 (Feed-grade calcium phosphate salt production system and method ) 是由 朱宇杰 张秋月 于 2020-08-10 设计创作，主要内容包括：本发明提出了一种饲料级磷酸钙盐生产系统及方法,涉及饲料生产的技术领域,一种饲料级磷酸钙盐生产系统,包括依次通过管道连通的脱硫脱重反应槽、沉清槽、一级中和反应槽、一级浓密机、二级中和反应槽、二级沉清槽、DCP反应槽、二级浓密机、第一离心机和磷酸钙盐生产装置,此系统流程简单,装置设备可大型化,降低成本,易于生产,此外本发明还提出一种饲料级磷酸钙盐生产方法,其步骤包括原料脱杂、混合料浆中和、生产饲料级磷酸钙盐,能够充分利用物料资源,将磷酸净化产生的渣酸作为原料,提高磷的回收利用率,不产白肥,降低原料消耗,节约资源,降低成本,产品质量高,产品可多元化。(The invention provides a feed-grade calcium phosphate production system and a method, relating to the technical field of feed production, the feed-grade calcium phosphate production system comprises a desulfurization and de-weighting reaction tank, a settling tank, a primary neutralization reaction tank, a primary thickener, a secondary neutralization reaction tank, a secondary settling tank, a DCP reaction tank, a secondary thickener, a first centrifuge and a calcium phosphate production device which are sequentially communicated through pipelines, the system has simple flow, the device equipment can be enlarged, the cost is reduced, the production is easy, in addition, the invention also provides a feed-grade calcium phosphate production method, the steps comprise raw material impurity removal, slurry neutralization and feed-grade calcium phosphate production, the material resources can be fully utilized, the slag acid generated by phosphoric acid purification is taken as the raw material, the recovery utilization rate of phosphorus is improved, no white fertilizer is produced, the raw material consumption is reduced, the resources are saved, the cost is reduced, the product quality is high, and the product can be diversified.)

1. The utility model provides a feed level calcium phosphate production system, its characterized in that, includes that the desulfurization that loops through the pipeline intercommunication takes off heavy reaction tank, precipitation groove, one-level neutralization reaction tank, one-level thickener, second grade neutralization reaction tank, second grade precipitation groove, DCP reaction tank, second grade thickener, first centrifuge and calcium phosphate apparatus for producing, still includes first material recovery pipeline, second material recovery pipeline, third material recovery pipeline, second grade precipitation groove pass through first material recovery pipeline with reaction tank intercommunication is neutralized to one-level, second grade thickener pass through second material recovery pipeline with reaction tank intercommunication is neutralized to one-level, first centrifuge pass through third material recovery pipeline with second grade thickener intercommunication.

2. The feed-grade calcium phosphate salt production system according to claim 1, further comprising a slag treatment system, wherein the slag treatment system comprises a second centrifuge, a decalcification reaction tank and a third centrifuge which are sequentially communicated through a pipeline, the second centrifuge is communicated with the primary thickener through a pipeline, and further comprises a fourth material recovery pipeline and a fifth material recovery pipeline, the second centrifuge is communicated with the primary thickener through the fourth material recovery pipeline, and the third centrifuge is communicated with the desulfurization and delignification reaction tank through the fifth material recovery pipeline.

3. The feed-grade calcium phosphate salt production system of claim 1, further comprising a phosphoric acid concentration and purification system, wherein the phosphoric acid concentration and purification system is respectively communicated with the desulfurization and de-weighting reaction tank and the calcium phosphate salt production device through pipelines.

4. A method for producing feed-grade calcium phosphate salt, which comprises the steps of using the system for producing feed-grade calcium phosphate salt according to any one of claims 1 to 3, further comprising:

removing impurities from raw materials: feeding dilute phosphoric acid and slag acid into the desulfurization and de-weighting reaction tank, wherein the mass concentration of the dilute phosphoric acid is 25-26%, and P in the dilute phosphoric acid₂O₅55-60 percent of the mass percentage, and then adding phosphate rock pulp with the grade of 28-33 percent and the solid content of 62-65 percent to remove sulfuric acidAdding a sodium sulfide solution with the mass concentration of 8-12% to remove heavy metal ions, sending the reacted materials into the settling tank, and settling to obtain supernatant acid a;

neutralizing the mixed slurry: feeding the clear acid a into the primary neutralization reaction tank, adding calcium carbonate slurry with the solid concentration of 60-62% to perform primary neutralization reaction, controlling the pH of the reaction material to be 2.35-2.45, feeding the reacted material into a primary thickener to perform sedimentation, feeding the upper clear acid in the primary thickener into a secondary neutralization reaction tank after sedimentation, adding the calcium carbonate slurry with the solid concentration of 60-62% to perform secondary neutralization reaction, controlling the pH of the material to be 2.7-3.0, feeding the mixed material into the secondary sedimentation tank to perform sedimentation after reaction, obtaining the upper clear acid b after sedimentation, and feeding the bottom material into the primary neutralization reaction tank through the first material recovery pipeline to be recovered;

production of feed-grade calcium phosphate salt: feeding clear acid b into the DCP reaction tank, adding calcium carbonate slurry with the solid concentration of 60-62% for reaction to obtain calcium hydrophosphate slurry, adding lime milk for neutralization reaction, controlling the pH of the material to be 7-10, feeding the mixed material into a second-stage thickener for settling after the reaction, feeding supernatant liquid into a first-stage neutralization reaction tank for recovery through a second material recovery pipeline after settling, feeding bottom materials into a first centrifugal machine for filtration to obtain a DCP material with the water content of 12-16% and filtrate, wherein P in the DCP material₂O₅Feeding DCP material into the calcium phosphate production device, adding purified phosphoric acid with the mass concentration of 40-54% for reaction to obtain DCP or MDCP or MCP, and feeding the filtrate into the secondary thickener for recovery through the third material recovery pipeline.

5. The method for producing a feed-grade calcium phosphate salt according to claim 4, wherein the diluted phosphoric acid in the raw material impurity removal step contains P₂O₅With P content in the phosphorus ore pulp₂O₅The mass ratio of (A) to (B) is 7-11: 1.

6. The feed according to claim 4A process for producing a material-grade calcium phosphate salt, characterized in that P of the reaction slurry in the primary neutralization reaction tank in the step of neutralizing the mixed slurry₂O₅The mass fraction is 8-12%, the reaction temperature is 30-50 ℃, the reaction time is 1.0-2.5 hours, the reaction temperature in the secondary neutralization reaction tank is 30-50 ℃, and the reaction time is 1.0-2.5 hours.

7. The method for producing feed-grade calcium phosphate salt according to claim 4, further comprising the step of slag treatment: and after the materials in the step of neutralizing the mixed slurry are settled by the primary thickener, feeding the materials at the bottom into the second centrifuge for filtering, returning the filtrate in the second centrifuge to the primary thickener through the fourth material recovery pipeline, feeding the filter cake in the second centrifuge into the decalcification reaction tank, adding phosphoric acid and water for reacting and dissolving calcium hydrogen phosphate in the filter cake, adding sodium sulfate and sodium carbonate for impurity removal, feeding the reacted materials into the third centrifuge for filtering, returning the filtrate in the third centrifuge to the desulfurization and de-weighting reaction tank through the fifth material recovery pipeline, and discharging the filter cake in the third centrifuge to a slag yard for fixed-point stockpiling.

8. The method for producing feed-grade calcium phosphate according to claim 7, wherein in the step of treating the slag, P in the reaction slurry is dissolved out during the process of dissolving calcium hydrogen phosphate in the filter cake₂O₅7-10% of mass fraction, 45-50 ℃ of reaction temperature, 1.5-1.8 of slurry pH and 8-15 minutes of reaction time, wherein SO in the reaction slurry is removed by adding sodium sulfate and sodium carbonate₄ ^2-The mass fraction is 1.5-2%, the pH is controlled at 2.4-3.0, and the reaction time is 1.0-1.5 hours.

9. The method of claim 4, further comprising the step of phosphoric acid purification: will P₂O₅Feeding concentrated phosphoric acid with the mass ratio of 50-60% and the mass concentration of 45-48% into the phosphoric acid concentration and purification system to obtain P₂O₅Purified phosphoric acid and slag acid with the mass percentage of 40-47% and the mass concentration of 40-54%, sending the slag acid into the desulfurization and de-weighting reaction tank, and adding P₂O₅The purified phosphoric acid with the mass percentage of 43-47 percent and the mass concentration of 40-54 percent is sent to a calcium phosphate production device.

10. The method for producing feed-grade calcium phosphate according to claim 9, wherein the phosphoric acid concentration purification system in the phosphoric acid purification step purifies phosphoric acid by chemical defluorination or gas defluorination, and P in the purified phosphoric acid in the phosphoric acid purification step₂O₅The concentration ratio of F is 250-500, the MER is 0.05-0.11, and SO₄ ^2-1.5-3 percent of mass fraction, 1-8ppm of As, 1-8ppm of Pb, 1-8ppm of Cd and 1-53ppm of Cr.

Technical Field

The invention relates to the technical field of feed production, in particular to a system and a method for producing feed-grade calcium phosphate.

Background

Feed phosphates are the main inorganic feed additives and the feed phosphate production capacity has exceeded 1000 million tons worldwide. The production of phosphate feed has become large and centralized abroad, especially in developed countries. The variety reaches more than 20 varieties and comprises calcium saltThe traditional method mainly comprises a two-step neutralization method of wet-process phosphoric acid and a direct method for synthesizing wet-process phosphoric acid by reacting purified phosphoric acid with calcium carbonate powder, and the traditional method produces a large amount of white fertilizers as byproducts, the fertilizers can cause certain pollution to soil, the utilization rate of raw materials is low, resources are wasted, the direct method has high requirement on the quality of the raw material phosphorite, and the direct method needs to treat Fe in the phosphorite₂O₃、Al₂O₃The contents of MgO, Cr and the like are strictly controlled, and the value of the acid residue generated in the phosphoric acid purification process is low, so that the economic benefit of the device is influenced.

Disclosure of Invention

The invention aims to provide a production system of feed-grade calcium phosphate, which has simple flow, large-scale device and equipment, low cost and easy production.

The invention also aims to provide a feed-grade calcium phosphate production method realized by using the feed-grade calcium phosphate production system, which realizes the cyclic utilization of resources, can recycle the slag acid, improves the yield, reduces the cost, can diversify the product, and has high product quality and yield.

The technical problem to be solved by the invention is realized by adopting the following technical scheme.

On the one hand, the embodiment of the application provides a feed-grade calcium phosphate production system, including the desulfurization that loops through the pipeline intercommunication takes off heavy reaction tank, the setting tank, one-level neutralization reaction tank, one-level thickener, second grade neutralization reaction tank, second grade setting tank, DCP reaction tank, second grade thickener, first centrifuge and calcium phosphate apparatus for producing, still include first material recovery pipeline, second material recovery pipeline, third material recovery pipeline, above-mentioned second grade setting tank is through above-mentioned first material recovery pipeline and above-mentioned one-level neutralization reaction tank intercommunication, above-mentioned second grade thickener is through above-mentioned second material recovery pipeline and above-mentioned one-level neutralization reaction tank intercommunication, above-mentioned first centrifuge is through above-mentioned third material recovery pipeline and above-mentioned second grade thickener intercommunication.

Further, in some embodiments of the present invention, the present invention further includes a slag processing system, the slag processing system includes a second centrifuge, a decalcification reaction tank, and a third centrifuge sequentially connected through a pipeline, the second centrifuge is connected to the first-stage thickener through a pipeline, the present invention further includes a fourth material recovery pipeline and a fifth material recovery pipeline, the second centrifuge is connected to the first-stage thickener through the fourth material recovery pipeline, and the third centrifuge is connected to the desulfurization and de-weighting reaction tank through the fifth material recovery pipeline.

Further, in some embodiments of the present invention, the apparatus further comprises a phosphoric acid concentration and purification system, wherein the phosphoric acid concentration and purification system is respectively communicated with the desulfurization and de-weighting reaction tank and the calcium phosphate salt production apparatus through a pipeline.

On the other hand, the embodiment of the present application provides a method for producing feed-grade calcium phosphate salt by using the above system for producing feed-grade calcium phosphate salt, which includes the following steps:

removing impurities from raw materials: feeding diluted phosphoric acid and slag acid into the desulfurization and de-weighting reaction tank, wherein the mass concentration of the diluted phosphoric acid is 25-26%, and P in the diluted phosphoric acid is₂O₅Adding 28-33% grade phosphorite slurry with 62-65% solid content to remove sulfate radical, adding 8-12% sodium sulfide solution to remove heavy metal ion, feeding the reacted material into the above-mentioned precipitation tank, precipitating to obtain supernatant acid a;

neutralizing the mixed slurry: feeding the clear acid a into the primary neutralization reaction tank, adding calcium carbonate slurry with the solid concentration of 60-62% to perform primary neutralization reaction, controlling the pH of the reaction material to be 2.35-2.45, feeding the reacted material into a primary thickener to perform sedimentation, feeding the upper clear acid in the primary thickener into a secondary neutralization reaction tank after sedimentation, adding the calcium carbonate slurry with the solid concentration of 60-62% to perform secondary neutralization reaction, controlling the pH of the material to be 2.7-3.0, feeding the mixed material into the secondary sedimentation tank to perform sedimentation after reaction, obtaining the upper clear acid b after sedimentation, and feeding the bottom material into the primary neutralization reaction tank through the first material recovery pipeline to be recovered;

production of feed-grade calcium phosphate salt: feeding clear acid b into the DCP reaction tank, adding calcium carbonate slurry with the solid concentration of 60-62% for reaction to obtain calcium hydrophosphate slurry, adding lime milk for neutralization reaction, controlling the pH of the material to be 7-10, feeding the mixed material into a second-stage thickener for settling after the reaction, feeding supernatant into a first-stage neutralization reaction tank for recovery through a second material recovery pipeline after settling, feeding the bottom material into the first centrifuge for filtration to obtain a DCP material with the water content of 12-16% and filtrate, and feeding P in the DCP material₂O₅Wherein the concentration ratio of F is 300-500, MER is 0.04-0.07, As is 5-10ppm, Pb is 3-10ppm, Cd is 1-10ppm, and Cr is 5-9ppm, DCP material is fed into the calcium phosphate production device, purified phosphoric acid with mass concentration of 40-54% is added for reaction to obtain DCP or MDCP or MCP, and the filtrate is fed into the secondary thickener for recovery through the third material recovery pipeline.

Further, in some embodiments of the present invention, the diluted phosphoric acid in the raw material impurity removal step contains P₂O₅With P content in the phosphorus ore pulp₂O₅The mass ratio of (A) to (B) is 7-11: 1.

Further, in some embodiments of the present invention, the P of the reaction slurry in the primary neutralization reaction tank in the mixed slurry neutralization step is₂O₅The mass fraction is 8-12%, the reaction temperature is 30-50 ℃, the reaction time is 1.0-2.5 hours, the reaction temperature in the secondary neutralization reaction tank is 30-50 ℃, and the reaction time is 1.0-2.5 hours.

Further, in some embodiments of the present invention, the method further comprises a slag processing step: and (3) after the materials in the step of neutralizing the mixed slurry are settled by the primary thickener, feeding the bottom materials into the second centrifuge for filtration, returning the filtrate in the second centrifuge to the primary thickener through the fourth material recovery pipeline, feeding the filter cake in the second centrifuge into the decalcification reaction tank, adding phosphoric acid and water for reaction to dissolve calcium hydrogen phosphate in the filter cake, adding sodium sulfate and sodium carbonate for impurity removal, feeding the reacted materials into the third centrifuge for filtration, returning the filtrate in the third centrifuge to the desulfurization and de-weighting reaction tank through the fifth material recovery pipeline, and discharging the filter cake in the third centrifuge to a slag yard for fixed-point stacking.

Further, in some embodiments of the present invention, in the above-mentioned slag treatment step, P in the reaction slurry is dissolved out during calcium hydrogen phosphate in the filter cake₂O₅7-10% mass fraction, 45-50 deg.C reaction temperature, 1.5-1.8 pH of slurry, 8-15 min reaction time, and adding sodium sulfate and sodium carbonate to remove SO in the reaction slurry₄ ^2-The mass fraction is 1.5-2%, the pH is controlled at 2.4-3.0, and the reaction time is 1.0-1.5 hours.

Further, in some embodiments of the present invention, a phosphoric acid purification step is further included: will P₂O₅Feeding 50-60% by mass and 45-48% by mass concentrated phosphoric acid into the phosphoric acid concentration and purification system to obtain P₂O₅Purified phosphoric acid with the mass ratio of 40-47% and the mass concentration of 40-54% and slag acid are fed into the desulfurization and de-weighting reaction tank, and P is added₂O₅The purified phosphoric acid with the mass percentage of 43-47 percent and the mass concentration of 40-54 percent is sent to a calcium phosphate production device.

Further, in some embodiments of the present invention, the phosphoric acid concentration purification system in the phosphoric acid purification step purifies the phosphoric acid by chemical defluorination or gas defluorination, and P in the purified phosphoric acid in the phosphoric acid purification step₂O₅The concentration ratio of F is 250-500, the MER is 0.05-0.11, and SO₄ ^2-1.5-3 percent of mass fraction, 1-8ppm of As, 1-8ppm of Pb, 1-8ppm of Cd and 1-53ppm of Cr.

Compared with the prior art, the embodiment of the invention has at least the following advantages or beneficial effects:

the utility model provides a fodder level calcium phosphate production system, including the desulfurization that loops through the pipeline intercommunication and take off heavy reaction tank, the precipitation groove, one-level neutralization reaction tank, one-level thickener, second grade neutralization reaction tank, second grade precipitation groove, the DCP reaction tank, second grade thickener, first centrifuge and calcium phosphate apparatus for producing, still include first material recovery pipeline, second material recovery pipeline, third material recovery pipeline, above-mentioned second grade precipitation groove is through above-mentioned first material recovery pipeline and above-mentioned one-level neutralization reaction tank intercommunication, above-mentioned second grade thickener is through above-mentioned second material recovery pipeline and above-mentioned one-level neutralization reaction tank intercommunication, above-mentioned first centrifuge is through above-mentioned third material recovery pipeline and above-mentioned second grade thickener intercommunication.

The feed-grade calcium phosphate production system has the advantages that the whole system flow is simple, the device equipment can be enlarged, the investment cost is saved, the reaction can be more complete by arranging the multistage neutralization reaction tank and the multistage thickener, the product quality is improved, the byproduct materials can be recycled, the raw materials are saved, the yield is improved, the production cost is reduced, and the production is facilitated.

A production method of feed-grade calcium phosphate salt by using the production system of feed-grade calcium phosphate salt comprises the steps of removing impurities from raw materials, neutralizing mixed slurry and producing the feed-grade calcium phosphate salt.

The production method of the feed-grade calcium phosphate can fully utilize material resources, improve the recovery rate of byproducts, reduce the consumption of raw materials, improve the yield, save resources, reduce the cost, realize high product quality and diversify products.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

FIG. 1 is a schematic diagram of the structure of a feed-grade calcium phosphate salt production system in an embodiment of the present invention.

Icon: 1-a desulfurization and de-weighting reaction tank; 2-settling tank; 3-a first-stage neutralization reaction tank; 4-first-stage thickener; 5-a secondary neutralization reaction tank; 6-secondary settling tank; 7-DCP reaction tank; 8-a secondary thickener; 9-a first centrifuge; 10-a second centrifuge; 11-decalcification reaction tank; 12-a third centrifuge; 13-a first material recovery pipeline; 14-a second material recovery pipeline; 15-a third material recovery pipeline; 16-a fourth material recovery pipeline; 17-a fifth material recovery pipeline.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail below with reference to specific examples.

As shown in fig. 1, a feed-grade calcium phosphate production system comprises a desulfurization and de-weighting reaction tank 1, a settling tank 2, a primary neutralization reaction tank 3, a primary thickener 4, a secondary neutralization reaction tank 5, a secondary settling tank 6, a DCP reaction tank 7, a secondary thickener 8, a first centrifuge 9, a calcium phosphate production device which are sequentially communicated through pipelines, and further comprises a first material recovery pipeline 13, a second material recovery pipeline 14 and a third material recovery pipeline 15, wherein the secondary settling tank 6 is communicated with the primary neutralization reaction tank 3 through the first material recovery pipeline 13, the secondary thickener 8 is communicated with the primary neutralization reaction tank 3 through the second material recovery pipeline 14, and the first centrifuge 9 is communicated with the secondary thickener 8 through the third material recovery pipeline 15.

In the above embodiment, the material is sent into the desulfurization and de-weighting reaction tank 1 to remove impurities in the material through reaction, then sent into the settling tank 2 to settle, the clear liquid is sent into the primary neutralization reaction tank 3 to perform primary neutralization reaction, the clear liquid is sent into the primary thickener 4 to settle after reaction, the clear liquid is sent into the secondary neutralization reaction tank 5 to perform secondary neutralization reaction, the clear liquid is sent into the secondary settling tank 6 to settle after reaction, the settled bottom material can be recycled and sent into the primary neutralization reaction tank 3 to perform reaction and reuse, the clear liquid is sent into the DCP reaction tank 7 to perform reaction, the reacted material is sent into the secondary thickener 8 to settle, the settled clear liquid can be recycled and sent into the primary neutralization reaction tank 3 to perform reaction and reuse, the bottom material is sent into the first centrifuge 9 to be filtered, and the filtered material is sent into the calcium phosphate production device to produce feed-grade calcium phosphate, the whole system flow is simple, the device can be enlarged, the investment cost is saved, the reaction can be more complete by arranging the multistage neutralization reaction tank and the multistage thickener, the product quality is improved, the byproduct materials can be recycled, the raw materials are saved, the production cost is reduced, and the production is facilitated.

As shown in fig. 1, in some embodiments of the present invention, the present invention further includes a slag processing system, the slag processing system includes a second centrifuge 10, a decalcification reaction tank 11, and a third centrifuge 12, which are sequentially communicated through a pipeline, the second centrifuge 10 is communicated with the first-stage thickener 4 through a pipeline, the present invention further includes a fourth material recovery pipeline 16 and a fifth material recovery pipeline 17, the second centrifuge 10 is communicated with the first-stage thickener 4 through the fourth material recovery pipeline 16, and the third centrifuge 12 is communicated with the desulfurization and de-weighting reaction tank 1 through the fifth material recovery pipeline 17.

In the above embodiment, the waste gas material treated by the primary thickener 4 is sent to the second centrifuge 10 for dehydration and filtration, the filtered filtrate can be recycled and sent to the primary thickener 4 for reaction and reuse, the filter cake is sent to the decalcification reaction tank 11 for reaction and impurity removal, the residual recyclable substances are dissolved out, the toxic substances and the like are precipitated, the reacted precipitate mixture is sent to the third centrifuge 12 for filtration, the filtrate can be recycled and sent to the desulfurization and de-weighting reaction tank 1 for reaction and reuse, the filter cake is discharged to a slag yard for fixed-point stacking, and the residual usable substances in the waste slag can be effectively recycled through the slag treatment system, so that the yield is improved, the raw material consumption can be further reduced, and the production cost is saved.

As shown in fig. 1, in some embodiments of the present invention, a phosphoric acid concentration and purification system is further included, and the phosphoric acid concentration and purification system is respectively communicated with the desulfurization and de-weighting reaction tank 1 and the calcium phosphate salt production apparatus through a pipeline.

In the above embodiment, the purified phosphoric acid produced by the phosphoric acid concentration and purification system can be used as a raw material and sent to the calcium phosphate production device for calcium phosphate production, and the obtained by-product acid sludge can also be used as a raw material and sent to the desulfurization and de-weighting reaction tank 1 to participate in the subsequent production reaction, so that the materials are fully utilized, the raw material consumption is reduced, and the production cost is reduced.

As shown in fig. 1, a method for producing feed-grade calcium phosphate salt by using the above system for producing feed-grade calcium phosphate salt comprises the following steps:

removing impurities from raw materials: feeding diluted phosphoric acid and slag acid into the desulfurization and de-weighting reaction tank 1, wherein the mass concentration of the diluted phosphoric acid is 25-26%, and P in the diluted phosphoric acid and the slag acid₂O₅Adding 28-33% grade phosphorite slurry with 62-65% solid content to remove sulfate radical, adding 8-12% sodium sulfide solution to remove heavy metal ion, feeding the reacted material into the settling tank 2, settling to obtain supernatant acid a;

neutralizing the mixed slurry: feeding the clear acid a into the primary neutralization reaction tank 3, adding calcium carbonate slurry with the solid concentration of 60-62% for primary neutralization reaction, controlling the pH of the reaction material to be 2.35-2.45, feeding the reacted material into a primary thickener 4 for settling, feeding the upper clear acid in the primary thickener 4 into a secondary neutralization reaction tank 5 after settling, adding calcium carbonate slurry with the solid concentration of 60-62% for secondary neutralization reaction, controlling the pH of the material to be 2.7-3.0, feeding the mixed material into the secondary settling tank 6 for settling after reaction, obtaining the upper clear acid b after settling, and feeding the bottom material into the primary neutralization reaction tank 3 for recycling through the first material recycling pipeline 13;

production of feed-grade calcium phosphate salt: feeding clear acid b into the DCP reaction tank 7, adding calcium carbonate slurry with the solid concentration of 60-62% for reaction to obtain calcium hydrophosphate slurry, adding lime milk for neutralization reaction, controlling the pH of the material to be 7-10, feeding the mixed material into a secondary thickener 8 for settling after the reaction, feeding supernatant liquid into a primary neutralization reaction tank 3 for recovery through a second material recovery pipeline 14 after settling, feeding bottom materials into a first centrifugal machine 9 for filtration to obtain DCP materials with the water content of 12-16% and filtrate, and feeding P in the DCP materials₂O₅The concentration ratio of F is 300-500, the MER is 0.04-0.07, As5-10ppm, 3-10ppm Pb, 1-10ppm Cd, 5-9ppm Cr, feeding DCP material into the calcium phosphate production device, adding purified phosphoric acid with mass concentration of 40-54% for reaction to obtain DCP, MDCP or MCP, and feeding the filtrate into the secondary thickener 8 through the third material recovery pipeline 15 for recovery.

In the above embodiment, the raw material impurity removal is performed first, the slag acid generated in the phosphoric acid purification process can be recycled by incorporating the slag acid into the dilute phosphoric acid, the production cost is reduced, the sulfate radical and heavy metal ions are removed by the reaction, thereby the product quality is ensured, the reacted material is sent into the first-stage neutralization reaction tank 3 for neutralization of the mixed slurry, the reaction is ensured to be complete by multi-stage neutralization reaction and controlling the pH of the mixed slurry, the product quality is ensured, the subsequent process is ensured to be carried out smoothly, the bottom material after the reaction precipitation can be recycled and sent into the first-stage neutralization reaction tank 3 for continuous production reaction, the material resource is fully utilized, the product yield is improved, the raw material consumption is reduced, the production cost is saved, the clear liquid after the reaction precipitation is sent into the DCP reaction tank 7 for producing feed-grade calcium phosphate salt, the reaction ensures the product quality by controlling the pH of, the reacted materials are filtered by the first centrifugal machine 9 to obtain DCP materials, filtrate can be sent to the second-stage thickener 8 to be recycled, so that the raw material consumption is reduced, the production cost is saved, and the product yield is improved.

Further, in some embodiments of the present invention, the diluted phosphoric acid in the raw material impurity removal step contains P₂O₅With P in the phosphorus ore pulp₂O₅The mass ratio of (A) to (B) is 7-11: 1.

In the above embodiment, the P content in the phosphoric acid is controlled by controlling the adding proportion of the phosphorus ore pulp₂O₅With P contained in the phosphorus ore₂O₅The mass ratio of (A) to (B) is 7-11:1, so that the raw material consumption is saved, and the production cost is reduced.

Further, in some embodiments of the present invention, the amount of sodium sulfide added in the above-mentioned raw material impurity removal step is controlled to be 1.5 times the amount calculated from the theoretical consumption.

In the embodiment, the product quality can be ensured by controlling the addition amount of sodium sulfide to be 1.5 times of the theoretical consumption calculation amount, and the production is facilitated.

Further, in some embodiments of the present invention, the P of the reaction slurry in the primary neutralization reaction tank 3 in the mixed slurry neutralization step is₂O₅The mass fraction is 8-12%, the reaction temperature is 30-50 ℃, the reaction time is 1.0-2.5 hours, the reaction temperature in the secondary neutralization reaction tank 5 is 30-50 ℃, and the reaction time is 1.0-2.5 hours.

In the above examples, P in the slurry of the first-stage neutralization reaction in the above-mentioned mixed slurry neutralization step was controlled₂O₅The mass fraction is 8-12%, the reaction temperature is 30-50 ℃, the reaction time is 1.0-2.5 hours, the reaction temperature of the secondary neutralization reaction is 30-50 ℃, the reaction time is 1.0-2.5 hours, the smooth reaction is ensured, and the production is facilitated.

As shown in fig. 1, in some embodiments of the invention, the method further comprises a slag treatment step: after the materials in the step of neutralizing the mixed slurry are settled by the primary thickener 4, the materials at the bottom are sent to the second centrifuge 10 for filtration, the filtrate in the second centrifuge 10 is returned to the primary thickener 4 through the fourth material recovery pipeline 16, the filter cake in the second centrifuge 10 is sent to the decalcification reaction tank 11, then phosphoric acid and water are added for reaction to dissolve out calcium hydrogen phosphate in the filter cake, sodium sulfate and sodium carbonate are added for impurity removal, the materials after reaction are sent to the third centrifuge 12 for filtration, the filtrate in the third centrifuge 12 is returned to the desulfurization and de-weighting reaction tank 1 through the fifth material recovery pipeline 17, and the filter cake in the third centrifuge 12 is discharged to a slag yard for fixed-point stockpiling.

In the above embodiment, through the above slag treatment step, the bottom material obtained after settling the primary thickener 4 can be recycled and put into production after reaction treatment of the second centrifuge 10 and the decalcification reaction tank 11, so that the raw material consumption is reduced, the production cost is saved, and the phosphorus yield is improved.

Further, in some embodiments of the present invention, in the above-mentioned slag treatment step, P in the reaction slurry is dissolved out during calcium hydrogen phosphate in the filter cake₂O₅7-10 percent of mass fraction, 45-50 ℃ of reaction temperature, 1.5-1.8 of slurry pH and 8-15 minutes of reaction time, and adding sodium sulfate and sodium carbonate to remove SO in the reaction slurry in the process of impurity removal₄ ^2-The mass fraction is 1.5-2%, the pH is controlled at 2.4-3.0, and the reaction time is 1.0-1.5 hours.

In the above examples, the slurry P was neutralized by controlling the reaction of calcium hydrogen phosphate dissolving out of the filter cake₂O₅7-10% mass fraction, 45-50 deg.C reaction temperature, 1.5-1.8 pH value, 8-15 min reaction time, and removing impurity₄ ^2-The mass fraction is 1.5-2%, the pH is controlled at 2.8-3.0, and the reaction time is 1.0-1.5 hours, so that the smooth reaction is ensured, the reaction is complete, and the production is facilitated.

Further, in some embodiments of the present invention, a phosphoric acid purification step is further included: will P₂O₅Feeding 50-60% by mass and 45-48% by mass concentrated phosphoric acid into the phosphoric acid concentration and purification system to obtain P₂O₅Purified phosphoric acid with the mass ratio of 40-47% and the mass concentration of 40-54% and slag acid are fed into the desulfurization and de-weighting reaction tank 1, and P is added₂O₅The purified phosphoric acid with the mass percentage of 43-47 percent and the mass concentration of 40-54 percent is sent to a calcium phosphate production device.

In the above embodiment, the purified phosphoric acid obtained by the phosphoric acid purification step can be used as a raw material and fed into the calcium phosphate salt production apparatus to produce feed-grade calcium phosphate salt, and the by-product slag acid can be used as a raw material and fed into the desulfurization and de-weighting reaction tank 1 to continue the subsequent reaction, so that the materials can be fully utilized, the raw material consumption can be reduced, the production cost can be saved, and the product yield can be improved.

Further, in some embodiments of the present invention, the phosphoric acid concentration purification system in the phosphoric acid purification step purifies the phosphoric acid by chemical defluorination or gas defluorination, and the phosphoric acid purification step is performed by using the phosphoric acid concentration purification systemPurification of P in phosphoric acid in the formation step₂O₅The concentration ratio of F is 250-500, the MER is 0.05-0.11, and SO₄ ^2-1.5-3 percent of mass fraction, 1-8ppm of As, 1-8ppm of Pb, 1-8ppm of Cd and 1-53ppm of Cr.

In the embodiment, phosphoric acid is purified by chemical defluorination or gas defluorination, so that the purification is more facilitated, the product quality can be ensured, and the subsequent production link can be ensured to be smoothly carried out.

The features and properties of the present invention are described in further detail below with reference to examples.