CN112429709B - Method for graded production of wet-process phosphoric acid - Google Patents
Method for graded production of wet-process phosphoric acid Download PDFInfo
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- CN112429709B CN112429709B CN202011430798.5A CN202011430798A CN112429709B CN 112429709 B CN112429709 B CN 112429709B CN 202011430798 A CN202011430798 A CN 202011430798A CN 112429709 B CN112429709 B CN 112429709B
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Abstract
The invention discloses a method for graded production of wet-process phosphoric acid, and relates to the technical field of wet-process phosphoric acid production. The flotation concentrate slurry is dewatered by stages to obtain concentrate slurry filter cake, the filter cake and industrial sulfuric acid are extracted by a semi-water-dihydrate recrystallization concentrated acid process to obtain concentrated phosphoric acid, the generated concentrated phosphoric acid is sent to a desulfurization reaction tank to be subjected to desulfurization reaction with the concentrate slurry, the desulfurized concentrated phosphoric acid is sent to a thickener for clarification, clarified clear acid overflows to a decolorization reaction tank and is decolorized by active carbon, and finally, the concentrate slurry filter press is used for filter pressing to obtain P2O5≥40wt％、SO4 2‑The high-quality fertilizer-grade phosphoric acid with the solid content of less than or equal to 0.5 wt%, the MER of less than or equal to 0.2 wt% and the other part of the concentrated ore pulp after classification, slag acid formed after sedimentation of a thickener and filter residue generated by filter pressing after decoloration are sent to a dihydrate phosphoric acid production device. Fractional reduction of partial sesquioxide without reduction of P2O5And (3) grading and utilizing the concentrate pulp under the condition of recovery rate, and preparing high-concentration phosphoric acid by using the filter cake to further reduce the content of impurities in the phosphoric acid.
Description
Technical Field
The invention relates to the technical field of wet-process phosphoric acid production, in particular to a method for graded production of wet-process phosphoric acid.
Background
Wet-process phosphoric acid is an important raw material for producing phosphate fertilizers and phosphorus-containing feeds, and at present, strong inorganic acid (sulfuric acid, nitric acid, hydrochloric acid and the like) is mainly used for extracting and decomposing phosphate ore pulp or phosphate ore powder to produce phosphoric acid in the preparation of the wet-process phosphoric acid, wherein the sulfuric acid method is most used. The mineral powder is gradually replaced by the ore pulp due to the severe operation environment, and on the other hand, the phosphorite is gradually depleted due to the phosphorite resource, the phosphorite grade is continuously reduced, the content of impurities such as iron, magnesium, aluminum and the like in the phosphorite is gradually increased, so that the phosphorite needs to be subjected to flotation, and the phosphorite can be used for wet-process phosphoric acid production after phosphorus is enriched and a part of impurities are removed. Even if the obtained wet-process phosphoric acid still has high impurity content, the requirement of preparing fertilizer feed can be met after purification, and particularly, when the wet-process phosphoric acid is used for producing 64 percent and 66 percent of high-nitrogen high-quality diammonium phosphate export products, the quality index is difficult to reach the standard.
The main index parameter of the ore pulp after flotation at present is P2O5The concentration is about 28.50 wt%, the solid content is 58-61 wt%, and Fe2O31.12 wt% of Al2O3The content was 1.51% by weight, and the MER value was 0.119. The impurity content in the ore pulp is high, the scaling blockage of a filter system can be accelerated in the production process, wherein part R2O3Oxides, in particular Al2O3Impurities separated out in the concentration are difficult to settle, the yield of the clear acid is reduced, and the treatment cost is increased. When high-nitrogen high-quality diammonium phosphate export products are produced, the appearance transparency of the products is poor, and the product sale is directly influenced. If be used for producing water-soluble fertilizer, impurity is difficult to dissolve and finally leads to the sprinkling irrigation facility to block up.
Al in phosphoric ore pulp2O3Part of the phosphate ore is separated during the phosphorite flotation, but a medicament is required to be added for multiple times of flotation for further removal, so that the flotation process flow is invisibly lengthened, the equipment and medicament investment are increased, and the production cost is greatly improvedThis is not economical.
Patent CN106145074A proposes a method for reducing Al in wet-process phosphoric acid in production2O3The wet-process phosphoric acid process with the content is characterized in that after extracted wet-process phosphoric acid reacts with ground phosphate rock at the temperature of 60-90 ℃, fluoride is added to enable aluminum to be removed after precipitation, but fluorine is introduced in the process, one part of the fluorine can be separated from metal impurities such as aluminum and the like, but the other part of the fluorine can be remained in the phosphoric acid, and the fluorine removal cost of subsequent phosphoric acid is invisibly increased.
Of course, it is also possible to remove a portion of the Al after wet-process phosphoric acid formation by other chemical precipitation methods or by other purification methods, such as volumetric extraction, crystallization, ion exchange, electrodialysis, membrane separation, etc2O3And the like, but the treatment steps become complicated in all the aspects, and the production cost is inevitably increased.
Disclosure of Invention
The invention aims to provide a method for graded production of wet-process phosphoric acid, which solves the problem that Al is difficult to efficiently and quickly remove in the existing wet-process phosphoric acid production2O3To (3) is described.
In order to solve the technical problems, the invention adopts the following technical scheme: the method for graded production of wet-process phosphoric acid is characterized by comprising the following steps of:
(1) classifying the floated concentrate phosphorus pulp by using a cyclone, introducing the pulp at the top of the cyclone into a phosphoric acid production device by a two-water method for production, and dehydrating and filter-pressing the thick pulp at the bottom of the cyclone by using a pressure filter to obtain a concentrate pulp filter cake with the water content of less than or equal to 16%;
(2) conveying the refined pulp filter cake obtained in the step (1) into a reaction tank for producing semi-water-dihydrate phosphoric acid, adding industrial sulfuric acid with the concentration of 98 wt%, reacting for 4-6 h at the reaction temperature of 92-100 ℃, and extracting to obtain a concentrated phosphoric acid mixture;
(3) adding the concentrated phosphoric acid mixture obtained in the step (2) into a desulfurization reaction tank, adding the bottom concentrated slurry subjected to cyclone classification according to a ratio, and uniformly stirring to obtain turbid finished acid;
(4) settling turbid finished acid obtained in the step (3) by a thickener, pumping slag acid settled at the bottom into a reaction tank of a phosphoric acid production device by a two-water method, and overflowing clear acid on the upper layer into a decoloring reaction tank;
(5) adding activated carbon into the decolorization reaction tank, stirring and mixing, filtering by a filter press, and conveying filter residues into a phosphoric acid production device by a dihydrate method to obtain a filtrate, namely finished phosphoric acid.
A further technical scheme is that the volume of the sulfuric acid added into each ton of filter cake in the step (2) is 0.25-0.35 m3Extracting P from the concentrated phosphoric acid mixture2O5The concentration is 40-42 wt%, the solid ratio of the semi-water slurry is 1.7-2.7, and the content of liquid-phase free sulfate radicals is 2.0-3.0 wt%.
The further technical scheme is that ore pulp at the top of the cyclone in the step (1) is settled and concentrated by an ore pulp thickener, the ore pulp at the bottom of the thickener enters a reaction tank of a dihydrate phosphoric acid production device, and clear water at the upper part is used as production water of an ore grinding device.
The further technical scheme is that the volume ratio of the concentrated phosphoric acid to the bottom concentrated slurry in the step (3) is 30-35: 1.
The further technical scheme is that in the step (3), the desulfurization reaction temperature is controlled to be 65-75 ℃, the reaction time is 4.5-5.5 hours, 4 stirrers are arranged in the desulfurization reaction tank, and the stirring speed of each stirrer is 50-60 r/min.
The further technical scheme is that in the step (5), the decoloring reaction temperature is controlled to be 55-65 ℃, the reaction time is 3.5-4.5 hours, 2 stirrers are arranged in the decoloring reaction tank, and the stirring speed of each stirrer is 50-60 r/min.
And (3) further adopting the technical scheme that the filter residue obtained in the step (5) is subjected to backwater and size mixing by a slag dam to be used as primary washing water of the gypsum filter cake in the phosphoric acid production by the dihydrate method, and water-soluble phosphorus in the filter residue is recovered.
The further technical scheme is that the active carbon in the step (5) is prepared by taking shells and sawdust as raw materials and carrying out carbonization, activation and refining, wherein methylene blue decoloration is more than or equal to 170mg/g, iodine adsorption value is more than or equal to 950mg/g, and the particle size content of 325 meshes is more than or equal to 90%.
The further technical proposal is that P in the finished phosphoric acid product2O5≥40wt％、SO4 2-Less than or equal to 0.5 wt%, less than or equal to 0.2 wt% of solid content and less than or equal to 0.10% of MER.
The reaction mechanism is as follows: the refined phosphorus ore pulp after flotation is subjected to centrifugal force in a cyclone, and Al2O3Because the particles have small and light molecular weight, part of the particles are discharged along with the upward vortex, so that Al in the underflow sand setting2O3Greatly reduces particles and also ensures that Al enters a wet-process phosphoric acid production device2O3The impurities are greatly reduced.
The filter cake obtained by filter pressing the underflow sand of the cyclone is extracted and reacted with sulfuric acid to prepare phosphoric acid, and the main chemical reaction of the semi-water-dihydrate recrystallization concentrated acid (two-step method) process is as follows:
the decomposition of the concentrate slurry filter cake in the phosphoric acid solution is carried out in two steps:
the first step is as follows: the phosphorite is firstly decomposed by phosphoric acid to generate monocalcium phosphate
Ca5F(PO4)3+10H3PO4+ solution ═ 3H3PO4+HF+5Ca(H2PO4)2+ solution
The second step is that: the monocalcium phosphate continues to react with sulfuric acid to produce phosphoric acid
5Ca(H2PO4)2+ solution + H2SO4＝＝＝10H3PO4+5CaSO4·1/2H2O + solution
At the same time, a number of reactions also occur:
CaCO3+H2SO4＝＝＝CO2+CaSO4+H2O
the general chemical reaction is as follows:
Ca5F(PO4)3+ solution +5H2SO4＝＝＝5CaSO4·1/2H2O + solution +3H3PO4+HF
During the conversion of hemihydrate crystals to dihydrate crystals, there are two main reactions:
conversion of hemihydrate to dihydrate crystals
CaSO4·1/2H2O+3/2H2O＝＝＝CaSO4·2H2O
In the pulp filter cake fed to the extraction reactor, about 5% of P is present2O5Precipitating simultaneously with the hemihydrate, this portion of the precipitate continuing with H2SO4Reaction takes place
3/2H2O+CaHPO4·1/2H2O+H2SO4＝＝＝CaSO4·2H2O+H3PO4
The concentrated phosphoric acid is desulfurized by concentrated ore pulp, and the main chemical reaction is as follows:
Ca5F(PO4)3+5H2SO4+10H2O＝＝＝5CaSO4·2H2O↓+3H3PO4+HF。
the desulfurized turbid finished acid is subjected to dense sedimentation, the supernatant clear acid is decolorized by active carbon and then is subjected to filter pressing again to obtain the P2O5≥40wt％、SO4 2-High quality fertilizer grade phosphoric acid with solid content less than or equal to 0.5 wt%, MER less than or equal to 0.2 wt%, Al in the finished product acid2O3The content is less than or equal to 1.04wt percent.
Compared with the prior art, the invention has the beneficial effects that:
1. the refined phosphorus ore pulp after flotation is subjected to the action of centrifugal force in a cyclone, and Al2O3Because the particles have small and light molecular weight, part of the particles are discharged along with the upward vortex, so that Al in the underflow sand setting2O3Greatly reduces particles and also ensures that Al enters a wet-process phosphoric acid production device2O3The impurities are greatly reduced. In the actual production process, the detection shows that 25.33 percent of Al in the ore pulp after classification2O3The particles are discharged along with the upward vortex, and Al in filter cakes obtained by filter pressing in the underflow sand setting2O3The content is only 1.12 wt%.
2. The filter cake obtained by filter pressing the underflow grit of the cyclone is then reacted with sulfuric acid to prepare phosphoric acid, the use level of the sulfuric acid is not influenced by the concentration fluctuation of the flotation pulp, and the production is controlled accurately.And during the reaction, Fe2O3And Al2O3The impurities can generate corresponding phosphate precipitates which are discharged out of the system together with the phosphogypsum and follow P in the phosphoric acid2O5Increase in concentration, Fe2O3And Al2O3The solubility of the phosphate precipitate of impurities in the phosphoric acid is reduced to precipitate out, so that the impurities in the phosphoric acid are further reduced.
3. Finished acid P2O5≥40wt％、SO4 2-Not more than 0.5 wt%, solid content not more than 0.2 wt%, MER not more than 0.10, Al2O3The content is less than or equal to 1.04 wt%, and the product can be directly used for producing phosphorus-containing feed, and the produced high-nitrogen high-quality diammonium phosphate product has mellow appearance, saturated color and high product quality.
4. In the process, the top ore pulp after grading in the step (1) is firstly settled and concentrated in an ore pulp thickener, the ore pulp at the bottom of the thickener is supplied to an ore pulp tank of a 13-million-ton/year phosphoric acid dihydrate device through an underflow pump for storage, and then is metered by an ore pulp pump and pumped to a reaction tank of the 13-million-ton/year phosphoric acid dihydrate device. The produced differential acid with high impurity content is used for fertilizer plants to produce 60 percent of DAP, MAP and other domestic products with low nutrient content. The clear water at the upper part of the thickener and the ore pulp water after pressure filtration overflow to a circulating water tank and are beaten to an ore grinding device through a circulating water pump to be used as the production water of the mill.
And (4) directly conveying the settled slag acid in the step (4) to a reaction tank of a 20 ten thousand ton/year dihydrate phosphoric acid device by a bottom flow pump at the bottom of a thickener.
And (5) returning and size-mixing the filter residue subjected to decolorization and filtration in the step (5) by using a slag dam, pumping the filter residue to a sewage collecting tank of a 20-kiloton/year dihydrate phosphoric acid device by using a pump, further diluting the filter residue by using sewage to reduce the solid content, finally pumping the filter residue to a filter of the 20-kiloton/year dihydrate phosphoric acid device by using a pump with a controlled amount to be used as primary washing water of a gypsum filter cake, and recovering water-soluble phosphorus in the filter residue.
The grading production mode can prepare high-end fertilizer-grade phosphoric acid at one time and can also prepare phosphoric acid for producing low-end fertilizers, thereby solving the requirement on the high-end and low-end fertilizers at the same time and greatly improving the market competitiveness of the product.
Drawings
FIG. 1 is a process flow diagram of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Example 1
The wet-process phosphoric acid grading production method comprises the following steps:
and step A, carrying out secondary classification on the flotation concentrate pulp by using a cyclone, carrying out dehydration from the concentrate pulp at the lower bottom of the classified impurities to step B, carrying out sedimentation and concentration on the concentrate pulp at the top with high impurities by using an pulp thickener, feeding the ore pulp at the bottom of the thickener into a reaction tank of a 13 ten thousand ton/year dihydrate phosphoric acid production device, and taking clear water at the upper part as production water of an ore grinding device.
And B, dehydrating the bottom concentrate pulp with low impurities in the step A by using a pressure filter, and performing filter pressing to form a concentrate pulp filter cake, wherein the water content of the filter cake is controlled to be 14-16 wt%. The filtrate is used for the water for the phosphorite grinding device.
And C, conveying the filter cake of the concentrate pulp to a reaction tank of a semi-water-dihydrate phosphoric acid device after being measured by a chain plate scale, and extracting concentrated phosphoric acid from industrial sulfuric acid by adopting a semi-water-dihydrate recrystallization concentrated acid (two-step method) process. In the process, concentrated sulfuric acid with the concentration of 98 wt% is used, and 0.25m is added into each ton of filter cake3The reaction temperature of the concentrated sulfuric acid is 92-95 ℃, and the reaction time is controlled to be 4-4.5 h. After extraction, 40-41 wt% of P can be directly produced2O5The liquid-solid ratio of the concentrated phosphoric acid mixture with the concentration is controlled to be 1.7-2.1, and the content of liquid-phase free sulfate radicals is 2.0-3.5 wt%;
d, metering the concentrated phosphoric acid mixture produced by the semi-hydrated-dihydrate phosphoric acid device, adding the metered concentrated phosphoric acid mixture into a desulfurization reaction tank, simultaneously adding the bottom concentrated slurry graded by a cyclone according to the proportion control, stirring and mixing the bottom concentrated slurry by a stirring paddle of the desulfurization reaction tank to generate desulfurization reaction, sending the turbid finished acid after the reaction to a thickener for sedimentation, and according to the process requirements of a downstream production device,the content of liquid phase free sulfate radicals after desulfurization is less than or equal to 0.5 wt%. Wherein the adding amount of the concentrated phosphoric acid mixture is 15m3H, the addition of the bottom concentrated slurry is 0.5m3H is used as the reference value. The reaction temperature in the desulfurization tank is controlled to be 65-70 ℃, the reaction time is 4.5-5 h, 4 stirrers are arranged in the desulfurization reaction tank, and the stirring speed of each stirrer is 52 r/min.
And E, settling turbid finished acid by a thickener, overflowing upper layer clear acid to a decoloring reaction tank, and pumping slag acid formed after settling by the thickener to a 20 ten thousand ton/year dihydrate phosphoric acid device reaction tank from an underflow pump at the bottom of the thickener.
F, the amount of the activated carbon added into the decoloring reaction tank is controlled according to the proportion while the desulfurized phosphoric acid enters the decoloring reaction tank, and the specific amount is 1m3Adding 0.75 kg of activated carbon into phosphoric acid, stirring and mixing by a stirring paddle of a decoloring reaction tank, decoloring, and sending the decolored turbid finished acid to the step G for filter pressing. Wherein the decolorizing reaction temperature is controlled to be 55-60 ℃, the reaction time is 3.5-4 h, 2 stirrers are arranged in the decolorizing reaction tank, and the stirring speed of each stirrer is 55 r/min.
G, filtering the decolored turbid finished acid by using a plate-and-frame filter press to obtain a filtrate, wherein the final finished phosphoric acid is obtained by using the filtrate as a main component with the index of P2O5：39.53wt％、SO4 2-: 0.32 wt%, solid content: 0.13 wt%, MgO: 1.29 wt% Fe2O3：1.03wt％、Al2O3: 1.17 wt%, MER: 0.088. and (4) after the filter residue is subjected to slag dam backwater size mixing, taking the filter residue as primary washing water of a gypsum filter cake in the phosphoric acid production by the dihydrate method, and recovering water-soluble phosphorus in the filter residue.
Wherein, the operating principle of the cyclone in the step A is that under the action of centrifugal force, coarse and heavy particulate matters are thrown to the wall of the device and rotate downwards to be discharged together with the formed concentrated solution. And the smaller particulate matters are discharged along with the secondary upward swirling flow after being rotated to a certain degree. Impurity Al in concentrate pulp2O3The particles are small in molecular weight and light, and part of Al2O3The particles are easy to be discharged along with the secondary upward swirling vortex, so that Al in the settled sand discharged from the bottom of the cyclone is caused2O3The number of particles is reduced, and the particle size is reduced,thereby improving the quality of the concentrate pulp.
The pressure filter in the step B is an advanced solid-liquid separation device in the world at present, is produced by Shandong Laiwu coal mine machinery Co., Ltd and is an ideal device for reducing the water content of the flotation clean coal and dewatering the primary coal slime, and the Yunnan Yuntai red phosphorus chemical industry Co., Ltd is originally used for dewatering the clean ore pulp.
Furthermore, the semi-water-dihydrate recrystallization concentrated acid (two-step method) process in the step C is the only recrystallization process capable of directly producing concentrated phosphoric acid in the existing wet-process phosphoric acid process, and Fe is generated in the reaction process2O3And Al2O3The impurities can generate corresponding phosphate precipitates which are discharged out of the system together with the phosphogypsum and follow P in the phosphoric acid2O5Increase in concentration, Fe2O3And Al2O3The solubility of the phosphate precipitate as an impurity in phosphoric acid decreases, and the impurity in phosphoric acid decreases.
In addition, the activated carbon in the step F is the fruit shell activated carbon, and is mainly prepared by taking fruit shells and wood chips as raw materials and carrying out carbonization, activation and refining. Has the characteristics of large specific surface area, high strength, uniform granularity, developed pore structure, strong adsorption performance and the like. The decolorization of methylene blue is more than or equal to 170mg/g, the iodine adsorption value is more than or equal to 950mg/g, the particle size is as follows: 325 mesh is more than or equal to 90 percent.
Example 2
The wet-process phosphoric acid grading production method comprises the following steps:
and step A, carrying out secondary classification on the flotation concentrate pulp by using a cyclone, carrying out dehydration from the concentrate pulp at the lower bottom of the classified impurities to step B, carrying out sedimentation and concentration on the concentrate pulp at the top with high impurities by using an pulp thickener, feeding the ore pulp at the bottom of the thickener into a reaction tank of a 13 ten thousand ton/year dihydrate phosphoric acid production device, and taking clear water at the upper part as production water of an ore grinding device.
And B, dehydrating the bottom concentrate pulp with low impurities in the step A by using a pressure filter, and performing filter pressing to form a concentrate pulp filter cake, wherein the water content of the filter cake is controlled to be 13-15 wt%. The filtrate is used for the water for the phosphorite grinding device.
C, passing the concentrate pulp filter cake through a chain plateAfter being weighed, the mixture is conveyed to a reaction tank of a semi-water-dihydrate phosphoric acid device and is used for extracting concentrated phosphoric acid from industrial sulfuric acid by adopting a semi-water-dihydrate recrystallization concentrated acid (two-step method) process. In the process, concentrated sulfuric acid with the concentration of 98 wt% is used, and 0.3m is added into each ton of filter cake3The reaction temperature of the concentrated sulfuric acid is 94-98 ℃, and the reaction time is controlled to be 4.3-5 h. After extraction, 40.5-41.3 wt% P can be directly produced2O5The liquid-solid ratio of the concentrated phosphoric acid mixture with the concentration is controlled to be 2.0-2.4, and the content of liquid-phase free sulfate radicals is 2.5-2.8 wt%;
d, metering a concentrated phosphoric acid mixture produced by the semi-hydrated phosphoric acid-dihydrate phosphoric acid device, adding the concentrated phosphoric acid mixture into a desulfurization reaction tank, simultaneously adding the bottom concentrated slurry classified by a cyclone according to the proportion control, stirring and mixing the bottom concentrated slurry by a stirring paddle of the desulfurization reaction tank to generate desulfurization reaction, sending the turbid finished acid after the reaction to a thickener for sedimentation, and enabling the content of liquid-phase free sulfate radicals after desulfurization to be less than or equal to 0.5 wt% according to the process requirements of a downstream production device. Wherein the adding amount of the concentrated phosphoric acid mixture is 16m3H, the addition of the bottom concentrated slurry is 0.5m3H is used as the reference value. The reaction temperature in the desulfurization tank is controlled to be 68-72 ℃, the reaction time is 4.8-5.3 h, 4 stirrers are arranged in the desulfurization reaction tank, and the stirring speed of each stirrer is 56 r/min.
And E, settling turbid finished acid by a thickener, overflowing upper layer clear acid to a decoloring reaction tank, and pumping slag acid formed after settling by the thickener to a 20 ten thousand ton/year dihydrate phosphoric acid device reaction tank from an underflow pump at the bottom of the thickener.
F, the amount of the activated carbon added into the decoloring reaction tank is controlled according to the proportion while the desulfurized phosphoric acid enters the decoloring reaction tank, and the specific amount is 1m3Adding 1 kg of activated carbon into phosphoric acid, stirring and mixing by a stirring paddle of a decoloring reaction tank, decoloring, and delivering the decolored turbid finished acid to the step G for filter pressing. Wherein the decolorizing reaction temperature is controlled to be 58-62 ℃, the reaction time is 3.8-4.3 h, 2 stirrers are arranged in the decolorizing reaction tank, and the stirring speed of each stirrer is 60 r/min.
G, filtering the decolored turbid finished acid by using a plate-and-frame filter press to obtain a filtrate, wherein the final finished phosphoric acid is obtained by using the filtrate as a main component with the index of P2O5：40.56wt％、SO4 2-: 0.09 wt%, solid content: 0.10 wt%, MgO: 1.23 wt% Fe2O3：1.01wt％、Al2O3: 1.09 wt%, MER: 0.082. and (3) returning and size-mixing the filter residue through a residue dam to be used as primary washing water of a gypsum filter cake in the phosphoric acid production by the dihydrate method, and recovering water-soluble phosphorus in the filter residue.
Example 3
The wet-process phosphoric acid grading production method comprises the following steps:
and step A, carrying out secondary classification on the flotation concentrate pulp by using a cyclone, carrying out dehydration from the concentrate pulp at the lower bottom of the classified impurities to step B, carrying out sedimentation and concentration on the concentrate pulp at the top with high impurities by using an pulp thickener, feeding the ore pulp at the bottom of the thickener into a reaction tank of a 13 ten thousand ton/year dihydrate phosphoric acid production device, and taking clear water at the upper part as production water of an ore grinding device.
And B, dehydrating the bottom concentrate pulp with low impurities in the step A by using a pressure filter, and performing filter pressing to form a concentrate pulp filter cake, wherein the water content of the filter cake is controlled to be 12-14 wt%. The filtrate is used for the water for the phosphorite grinding device.
And C, conveying the refined pulp filter cake after being measured by a chain plate scale to a reaction tank of a semi-water-dihydrate phosphoric acid device, and extracting concentrated phosphoric acid from industrial sulfuric acid by adopting a semi-water-dihydrate recrystallization concentrated acid (two-step method) process. In the process, concentrated sulfuric acid with the concentration of 98 wt% is used, and 0.34m is added into each ton of filter cake3The reaction temperature of the concentrated sulfuric acid is 95-100 ℃, and the reaction time is controlled to be 4.8-5.8 h. After extraction, 41.8-42 wt% P can be directly produced2O5The liquid-solid ratio of the concentrated phosphoric acid mixture with the concentration is controlled to be 2.2-2.6, and the content of liquid-phase free sulfate radicals is 2.7-3.2 wt%;
d, metering a concentrated phosphoric acid mixture produced by the semi-hydrated phosphoric acid-dihydrate phosphoric acid device, adding the concentrated phosphoric acid mixture into a desulfurization reaction tank, simultaneously adding the bottom concentrated slurry classified by a cyclone according to the proportion control, stirring and mixing the bottom concentrated slurry by a stirring paddle of the desulfurization reaction tank to generate desulfurization reaction, sending the turbid finished acid after the reaction to a thickener for sedimentation, and enabling the content of liquid-phase free sulfate radicals after desulfurization to be less than or equal to 0.5 wt% according to the process requirements of a downstream production device. It is composed ofIn the middle, the adding amount of the concentrated phosphoric acid mixture is 17m3H, the addition of the bottom concentrated slurry is 0.5m3H is used as the reference value. The reaction temperature in the desulfurization tank is controlled to be 70-75 ℃, the reaction time is 5-5.5 h, 4 stirrers are arranged in the desulfurization reaction tank, and the stirring speed of each stirrer is 60 r/min.
And E, settling turbid finished acid by a thickener, overflowing upper layer clear acid to a decoloring reaction tank, and pumping slag acid formed after settling by the thickener to a 20 ten thousand ton/year dihydrate phosphoric acid device reaction tank from an underflow pump at the bottom of the thickener.
F, the amount of the activated carbon added into the decoloring reaction tank is controlled according to the proportion while the desulfurized phosphoric acid enters the decoloring reaction tank, and the specific amount is 1m3Adding 1.25 kg of activated carbon into phosphoric acid, stirring and mixing by a stirring paddle of a decoloring reaction tank, decoloring, and delivering the decolored turbid finished acid to the step G for filter pressing. Wherein the decolorizing reaction temperature is controlled at 60-65 ℃, the reaction time is 4-4.5 h, 2 stirrers are arranged in the decolorizing reaction tank, and the stirring speed of each stirrer is 58 r/min.
G, filtering the decolored turbid finished acid by using a plate-and-frame filter press to obtain a filtrate, wherein the final finished phosphoric acid is obtained by using the filtrate as a main component with the index of P2O5：41.11wt％、SO4 2-: 0.25 wt%, solid content: 0.15 wt%, MgO: 1.20 wt%, Fe2O3：1.06wt％、Al2O3: 0.99 wt%, MER: 0.079. and (3) returning and size-mixing the filter residue through a residue dam to be used as primary washing water of a gypsum filter cake in the phosphoric acid production by the dihydrate method, and recovering water-soluble phosphorus in the filter residue.
Although the invention has been described herein with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More specifically, various variations and modifications are possible in the component parts or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts or arrangements, other uses will also be apparent to those skilled in the art.
Claims (7)
1. The method for graded production of wet-process phosphoric acid is characterized by comprising the following steps of:
(1) classifying the floated concentrate slurry by using a cyclone, introducing the slurry at the top of the cyclone into a phosphoric acid production device by a two-water method for production, and dehydrating and filter-pressing the concentrated slurry at the bottom of the cyclone by using a pressure filter to obtain a concentrate slurry filter cake with the water content less than or equal to 16%;
(2) conveying the refined pulp filter cake obtained in the step (1) into a reaction tank for producing semi-water-dihydrate phosphoric acid, adding industrial sulfuric acid with the concentration of 98 wt%, reacting for 4-6 h at the reaction temperature of 92-100 ℃, and extracting to obtain a concentrated phosphoric acid mixture; p in the concentrated phosphoric acid mixture obtained by extraction2O5The concentration is 40-42 wt%;
(3) adding the concentrated phosphoric acid mixture obtained in the step (2) into a desulfurization reaction tank, adding the bottom concentrated slurry subjected to cyclone classification according to a ratio, and uniformly stirring to obtain turbid finished acid;
(4) settling turbid finished acid obtained in the step (3) by a thickener, pumping slag acid settled at the bottom into a reaction tank of a phosphoric acid production device by a two-water method, and overflowing clear acid on the upper layer into a decoloring reaction tank;
(5) adding activated carbon into a decolorization reaction tank, stirring and mixing, filtering by a filter press, and conveying filter residues into a phosphoric acid production device by a dihydrate method to obtain a filtrate, namely finished phosphoric acid;
in the step (1), the ore pulp at the top of the cyclone is settled and concentrated by an ore pulp thickener, the ore pulp at the bottom of the thickener enters a reaction tank of a dihydrate phosphoric acid production device, and clear water at the upper part is used as production water of an ore grinding device; and (5) returning and size-mixing the filter residue in the step (5) through a residue dam to be used as primary washing water of a gypsum filter cake in the phosphoric acid production by the dihydrate method, and recovering water-soluble phosphorus in the filter residue.
2. The method for graded production of wet process phosphoric acid according to claim 1, characterized in that: the volume of the sulfuric acid added into each ton of filter cake in the step (2) is 0.25-0.35 m3The semi-water slurry has a solid-to-solid ratio of 1.7-2.7 and liquid-phase free sulfurThe acid radical content is 2.0-3.0 wt%.
3. The method for graded production of wet process phosphoric acid according to claim 1, characterized in that: the volume ratio of the concentrated phosphoric acid to the bottom concentrated slurry in the step (3) is 30-35: 1.
4. The method for graded production of wet process phosphoric acid according to claim 1, characterized in that: in the step (3), the temperature of the desulfurization reaction is controlled to be 65-75 ℃, the reaction time is 4.5-5.5 hours, 4 stirrers are arranged in the desulfurization reaction tank, and the stirring speed of each stirrer is 50-60 r/min.
5. The method for graded production of wet process phosphoric acid according to claim 1, characterized in that: and (3) in the step (5), the decoloring reaction temperature is controlled to be 55-65 ℃, the reaction time is 3.5-4.5 hours, 2 stirrers are arranged in the decoloring reaction tank, and the stirring speed of each stirrer is 50-60 r/min.
6. The method for graded production of wet process phosphoric acid according to claim 1, characterized in that: the activated carbon in the step (5) is prepared by taking shells and sawdust as raw materials and carrying out carbonization, activation and refining, wherein methylene blue decoloration is more than or equal to 170mg/g, iodine adsorption value is more than or equal to 950mg/g, and the content of 325 meshes of particle size is more than or equal to 90%.
7. The method for graded production of wet process phosphoric acid according to claim 1, characterized in that: p in the finished phosphoric acid2O5≥40wt％、SO4 2-Less than or equal to 0.5 wt%, less than or equal to 0.2 wt% of solid content and less than or equal to 0.10% of MER.
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Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1201401A (en) * | 1996-07-10 | 1998-12-09 | 雷声工程师及建造者公司 | Method of recovering fluorine compounds from vapors exiting wet process phosphoric acid evaporators |
| CN102502548A (en) * | 2011-10-21 | 2012-06-20 | 湖北三宁化工股份有限公司 | Method for decolorizing industrial phosphoric acid |
| CN103303886A (en) * | 2013-06-28 | 2013-09-18 | 山东鲁北企业集团总公司 | Novel method for producing industrial phosphoric acid by purification with wet process phosphoric acid |
| WO2014178788A1 (en) * | 2013-05-02 | 2014-11-06 | Easymining Sweden Ab | Production of phosphate compounds from materials containing phosphorus and at least one of iron and aluminium |
| CN106185852A (en) * | 2016-06-30 | 2016-12-07 | 四川大学 | A kind of method utilizing phosphorus ore to prepare purifying phosphoric acid |
| CN106395775A (en) * | 2016-08-31 | 2017-02-15 | 郝付勇 | Method for filtering phosphoric acid extraction slurry |
| CN107381525A (en) * | 2017-08-01 | 2017-11-24 | 湖北大江化工集团有限公司 | Utilize the technique and device of mid-low grade collophanite ore production industrial monoammonium phosphate coproduction high-quality MAP |
| CN207294180U (en) * | 2017-08-01 | 2018-05-01 | 湖北大江化工集团有限公司 | Utilize the device of mid-low grade collophanite ore production industrial monoammonium phosphate |
| CN108455543A (en) * | 2018-02-07 | 2018-08-28 | 四川绵竹市盘龙矿物质有限责任公司 | A kind of the defoaming charging process and its device of phosphoric acid by wet process extraction reaction |
| CN211644608U (en) * | 2019-12-30 | 2020-10-09 | 龙蟒大地农业有限公司 | Phosphoric acid desulfurization system |
-
2020
- 2020-12-07 CN CN202011430798.5A patent/CN112429709B/en active Active
Patent Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1201401A (en) * | 1996-07-10 | 1998-12-09 | 雷声工程师及建造者公司 | Method of recovering fluorine compounds from vapors exiting wet process phosphoric acid evaporators |
| CN102502548A (en) * | 2011-10-21 | 2012-06-20 | 湖北三宁化工股份有限公司 | Method for decolorizing industrial phosphoric acid |
| WO2014178788A1 (en) * | 2013-05-02 | 2014-11-06 | Easymining Sweden Ab | Production of phosphate compounds from materials containing phosphorus and at least one of iron and aluminium |
| CN105263872A (en) * | 2013-05-02 | 2016-01-20 | 易开采瑞典有限公司 | Production of phosphate compounds from materials containing phosphorus and at least one of iron and aluminium |
| CN103303886A (en) * | 2013-06-28 | 2013-09-18 | 山东鲁北企业集团总公司 | Novel method for producing industrial phosphoric acid by purification with wet process phosphoric acid |
| CN106185852A (en) * | 2016-06-30 | 2016-12-07 | 四川大学 | A kind of method utilizing phosphorus ore to prepare purifying phosphoric acid |
| CN106395775A (en) * | 2016-08-31 | 2017-02-15 | 郝付勇 | Method for filtering phosphoric acid extraction slurry |
| CN107381525A (en) * | 2017-08-01 | 2017-11-24 | 湖北大江化工集团有限公司 | Utilize the technique and device of mid-low grade collophanite ore production industrial monoammonium phosphate coproduction high-quality MAP |
| CN207294180U (en) * | 2017-08-01 | 2018-05-01 | 湖北大江化工集团有限公司 | Utilize the device of mid-low grade collophanite ore production industrial monoammonium phosphate |
| CN108455543A (en) * | 2018-02-07 | 2018-08-28 | 四川绵竹市盘龙矿物质有限责任公司 | A kind of the defoaming charging process and its device of phosphoric acid by wet process extraction reaction |
| CN211644608U (en) * | 2019-12-30 | 2020-10-09 | 龙蟒大地农业有限公司 | Phosphoric acid desulfurization system |
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