CN109292744B - Method for producing wet-process phosphoric acid and α semi-hydrated phosphogypsum from medium-grade phosphate ore - Google Patents
Method for producing wet-process phosphoric acid and α semi-hydrated phosphogypsum from medium-grade phosphate ore Download PDFInfo
- Publication number
- CN109292744B CN109292744B CN201811022775.3A CN201811022775A CN109292744B CN 109292744 B CN109292744 B CN 109292744B CN 201811022775 A CN201811022775 A CN 201811022775A CN 109292744 B CN109292744 B CN 109292744B
- Authority
- CN
- China
- Prior art keywords
- slurry
- phosphoric acid
- phosphogypsum
- semi
- reaction
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B25/00—Phosphorus; Compounds thereof
- C01B25/16—Oxyacids of phosphorus; Salts thereof
- C01B25/18—Phosphoric acid
- C01B25/22—Preparation by reacting phosphate-containing material with an acid, e.g. wet process
- C01B25/222—Preparation by reacting phosphate-containing material with an acid, e.g. wet process with sulfuric acid, a mixture of acids mainly consisting of sulfuric acid or a mixture of compounds forming it in situ, e.g. a mixture of sulfur dioxide, water and oxygen
- C01B25/228—Preparation by reacting phosphate-containing material with an acid, e.g. wet process with sulfuric acid, a mixture of acids mainly consisting of sulfuric acid or a mixture of compounds forming it in situ, e.g. a mixture of sulfur dioxide, water and oxygen one form of calcium sulfate being formed and then converted to another form
- C01B25/231—Dihydrate-hemihydrate process
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F11/00—Compounds of calcium, strontium, or barium
- C01F11/46—Sulfates
- C01F11/466—Conversion of one form of calcium sulfate to another
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B22/00—Use of inorganic materials as active ingredients for mortars, concrete or artificial stone, e.g. accelerators, shrinkage compensating agents
- C04B22/08—Acids or salts thereof
- C04B22/14—Acids or salts thereof containing sulfur in the anion, e.g. sulfides
- C04B22/142—Sulfates
- C04B22/143—Calcium-sulfate
- C04B22/144—Phosphogypsum
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
Abstract
The invention relates to a method for producing wet-process phosphoric acid and α semi-hydrated phosphogypsum from medium-grade phosphate ore, which is an energy-saving and low-consumption wet-process phosphoric acid production method2O)13‑15％、ω(P2O5Insolubility is less than or equal to 0.25%, omega (P)2O5Solubility) is less than or equal to 0.1 percent. And the zero emission of the byproduct phosphogypsum is realized by a grading technology.
Description
Technical Field
The invention belongs to the technical field of phosphorite utilization, and particularly relates to a method for producing wet-process phosphoric acid and α semi-hydrated phosphogypsum from medium-grade phosphorite
Background
The resource reserves of phosphorite in China are abundant but not rich, the resource reserves of ore are found to be 176 hundred million tons, the basic reserves are 33 hundred million tons, but the reserves of high-grade phosphorite are low, P2O5The amount of the phosphorus-rich ore resource reserve ore with the content of more than 30 wt.% is only 16.6 hundred million tons. Phosphorite has been classified as a strategic mineral as a valuable non-renewable resource in the national mineral resource planning (2016-.
The main component of the industrial by-product phosphogypsum in the wet phosphoric acid process is calcium sulfate, phosphoric acid is the basic raw material for producing phosphorus chemical products, and 1 ton of phosphoric acid (100 wt.% P is prepared2O5Meter) produced about 5 tons of phosphogypsum. At present, the phosphogypsum piled by phosphate fertilizer enterprises in China exceeds 2.5 hundred million tons, the yield exceeds 7000 ten thousand tons per year, the comprehensive utilization rate of the phosphogypsum is only about 25 percent at present, and the phosphogypsum is mainly used for cement industry, low-end building material products, pit and roadbed filling, soil improvement and the like.
The phosphogypsum is taken as solid waste to cause great environmental pollution risk, and the current problem of phosphogypsum discharge is a great technical problem facing the wet process phosphoric acid industry in China.
At present, more than 80% of wet-process phosphoric acid in China adopts a traditional dihydrate process, and a few manufacturers adopt a semi-hydrate-dihydrate or one-step semi-hydrate process. The phosphorus yield of the traditional dihydrate method and the one-step semi-hydrate process is low and is only about 94 percent and 92 percent respectively, the impurity content in the gypsum is high, and the comprehensive utilization of the phosphogypsum is seriously restricted; the semi-hydrated-dihydrate process has high phosphorus yield and good gypsum quality, but the process has high requirement on phosphorite raw materials and is not suitable for most enterprises, and meanwhile, the dihydrate gypsum is obtained by the process, so that the comprehensive utilization cost is increased.
A two-step wet process phosphoric acid process (a semi-water-dihydrate process, a dihydrate-semi-water process) is gradually started, wherein the semi-water-dihydrate process has been industrialized in China and has the advantages of high acid concentration, high phosphorus yield and good energy-saving effect, but the problem is that a byproduct is dihydrate phosphogypsum, and high added value utilization cannot be directly carried out. However, the dihydrate-hemihydrate process is limited to literature description at present in China, and the research content mainly adopts high-grade mineral powder as a raw material, so that the dihydrate-hemihydrate process is not suitable for producing medium-low grade phosphorite.
Disclosure of Invention
In order to solve the technical problems, the invention provides a method for producing wet-process phosphoric acid and α hemihydrate phosphogypsum from medium-grade phosphate rock.
In order to realize the purpose of the invention, the invention adopts the following technical scheme:
a method for producing wet-process phosphoric acid and α hemihydrate phosphogypsum from medium-grade phosphate ore comprises the following steps:
step 1, decomposition reaction: adding 98 wt.% of concentrated sulfuric acid and 28-32 wt.% of phosphate ore slurry into a reaction tank, and simultaneously adding the dilute phosphoric acid in the subsequent step 4 to perform phosphate ore decomposition reaction, wherein the phosphate ore slurry is converted into dry basis, and the 98 wt.% of concentrated sulfuric acid is converted into pure H2SO4Conversion of dilute phosphoric acid to P2O5The mass ratio of the last three is 1 (0.16-0.32) to 1.3-1.6; controlling the temperature of the reaction tank to be 80-85 ℃, the reaction time to be 2.5-3 hours, and the reaction tank reaching the relative equilibrium state process index: free sulfate ion (SO)4 2-) The concentration is 10-20g/L, and the solid content of the mixed slurry is 24-26 wt.%;
step 2, solid-liquid separation: dividing the mixed slurry in the reaction tank into a first group of slurry and a second group of slurry, wherein the first group of slurry accounts for 44-50 wt% of the mixed slurry of the phosphorite decomposition reaction, and performing solid-liquid separation on the first group of slurry to obtain the phosphogypsum dihydrate (CaSO)4·2H2O) and finished phosphoric acid;
step 3, semi-water conversion reaction: mixing the second group of slurry and phosphogypsum dihydrate (CaSO)4·2H2O) is added into a crystal transformation tank, and 98 wt.% of concentrated sulfuric acid is added for semi-water transformation reaction, so that the phosphogypsum dihydrate (CaSO)4·2H2O) to α phosphogypsum hemihydrate (α -CaSO)4·0.5H2O), wherein the phosphate ore slurry is converted to dry basis and 98 wt.% of concentrated sulfuric acid added in the semi-water conversion reaction is converted to pure H2SO4The mass ratio of the two is 1 (0.48-0.64); the temperature of the crystal conversion tank is 100-104.5 ℃, the reaction time is 1.5-2 hours, and the crystal conversion tank reaches the relative equilibrium state process indexes: free sulfurAcid radical ion (SO 4)2-) The concentration is 160-180g/L, and the solid content of the slurry is controlled to be 21-23 wt% by adding dilute phosphoric acid in the subsequent step 4;
and 4, filtering and washing, namely performing three-stage cyclone separation on the slurry in the crystal conversion tank, mixing the slurry of the upper layer and the slurry of the bottom layer obtained after the three-stage cyclone separation, filtering and washing, and independently filtering and washing the slurry of the middle layer to obtain α semi-hydrated phosphogypsum and diluted phosphoric acid used for returning to the step 1 and the step 3.
The further technical scheme is as follows: the method further comprises the following steps:
and 5, neutralizing: by using Ca (OH)2Mixing the α phosphogypsum hemihydrate (α -CaSO)4·0.5H2O) to pH 7-8.
The invention has the beneficial effects that:
(1) the step 1 of the invention aims to decompose phosphorite as fully as possible in reaction time to obtain higher phosphorus recovery rate, and obtain complete, thick and uniform calcium sulfate crystals, thereby being beneficial to filtration and separation and full washing of phosphogypsum. Usually, the total 98 wt.% sulfuric acid required for phosphorite decomposition is added to the decomposition tank simultaneously with the phosphorite and dilute phosphoric acid, and the process actually comprises 98 wt.% sulfuric acid in CaSO4-H3PO4-H2SO4-H2Dispersed, dilute phosphoric acid H in O quaternary reaction system3PO4And 98 wt.% concentrated sulfuric acid to provide H+(with H)3PO4Predominantly in an amount of H2SO420-25 times of) and Ca in the phosphate ore particles2+Ca in supersaturated state2+With SO4 2-Calcium sulfate crystals are formed by collision. The present invention is to effectively inhibit spontaneous generation of hypercyte nuclei and Ca2+And SO4 2-The attachment of the phosphate rock decomposition tank is favorable for crystal growth, and the lower free sulfate radical (SO) is controlled by controlling the lower acid-ore ratio of the phosphate rock decomposition tank4 2-) The concentration ensures that the phosphorite completes the decomposition reaction under a low saturation system, more sulfuric acid is added into the crystal conversion process to promote the crystallization conversion, and the conversion process is SO4 2-Enters the decomposition tank in the form of dilute phosphoric acid solution and simultaneously makes full use of 98wt.% heat of dilution of concentrated sulfuric acid, heat of reaction.
Step 2 involves dividing the phosphate rock decomposition mixed slurry of step 1 into two parts, wherein 44-50 wt.% of the mixed slurry is separated by filtration to obtain P2O5Finished phosphoric acid and dihydrate phosphogypsum (CaSO) with a concentration of 35-42 wt%4·2H2And O), feeding the residual part of the slurry and the dihydrate phosphogypsum into a crystal conversion tank, and adding 98 wt.% of concentrated sulfuric acid to complete the semi-water conversion.
In some documents, it is described that the phosphorite decomposition slurry is completely separated by filtration, and then part of the dilute phosphoric acid and the washing water are returned to the decomposition tank to ensure the necessary process indexes of the semi-water process, and the defects of the step 2 are caused by increased filtration load, enlarged equipment scale, high energy consumption and reduced filtration efficiency. The invention has the advantages that: only part of phosphoric acid is extracted in the step 2, so that the scale of equipment related to the step 2, such as filtering equipment, is controlled; the aim of controlling the concentration and the solid content of the dilute phosphoric acid in the semi-water conversion process is achieved by adjusting the proportion of the two parts of slurry.
And step 3, crystal tank process indexes are as follows: the temperature is 100-104.5 ℃; free sulfate radical (SO)4 2-) Under the condition of concentration of 160-4·2H2O to α -CaSO4·1/2H2The conversion of O hemihydrate is carried out SO that 60-80 wt.% of the total amount of 98 wt.% of concentrated sulfuric acid theoretically required is added to the crystallization tank, the conversion temperature is raised to 100-104.5 ℃ by making full use of the heat of dilution with sulfuric acid, free Sulfate (SO)4 2-) The concentration reaches 160-180 g/L. Excess free sulfate radical (SO) after solid-liquid separation4 2-) Returning to the decomposition tank in the step 1 along with the diluted phosphoric acid to ensure free sulfate radical (SO) required by phosphogypsum crystallization4 2-) Controlling free sulfate radical (SO) in the decomposition tank in the step 14 2-)10-20g/L, maintaining the efficient decomposition of the phosphorite in a low saturation state to generate CaSO4 & 2H2And (4) crystallizing O, wherein the crystal is complete, thick and uniform.
In the step 4, three-stage cyclone separator is adopted to grade the semi-hydrated and semi-hydrated conversion reaction slurry to obtain mixed slurry of an upper layer and a bottom layer and middle layer slurry, the mixed slurry of the upper layer and the bottom layer is filtered to obtain α semi-hydrated phosphogypsumIs divided into complex components containing light organic matters, acid-insoluble impurities and loose and fine α -CaSO4·1/2H2α -CaSO with O crystal and complex structure4·1/2H2Filtering the intermediate layer slurry to obtain high-purity compact, complete and coarse hexagonal prism α -CaSO4·1/2H2The α semi-hydrated phosphogypsum of the O crystal realizes the grading of the byproduct α semi-hydrated phosphogypsum, creates conditions for the high-value utilization of the resource, and the component index of the α semi-hydrated phosphogypsum obtained by the invention is omega (H)2O)13-15％、ω(P2O5Insolubility is less than or equal to 0.25%, omega (P)2O5Solubility) is less than or equal to 0.1 percent. In addition, dilute phosphoric acid obtained after filtration and washing is returned to the step 1 and the step 3, and the dilute phosphoric acid contains 30 to 33 wt.% of P2O5。
The three-stage cyclone separation has the advantages of separating light acid insoluble impurities and α -CaSO with complex structure4·1/2H2The method combines and filters slurry of an upper layer and a bottom layer to obtain mixed α semi-hydrated phosphogypsum, which meets the requirements of quality and demand of a cement retarder.
The α semi-hydrated phosphogypsum as a byproduct in the step 5 has low content of residual phosphorus and free F, is beneficial to washing, has small acidity of phosphogypsum, and greatly reduces the amount of lime water consumed for neutralization, the dosage of quicklime (90 wt.% CaO) required for neutralizing the phosphogypsum by the traditional phosphoric acid production device by a dihydrate method to the pH value of 5-8 is 8.3-16kg/t of phosphogypsum, and the dosage of the quicklime required for neutralizing α semi-hydrated phosphogypsum to the same pH value is only 4-13 wt.% of the dosage of the quicklime required for the phosphogypsum by the dihydrate method.
(2) Compared with the 'one-step method dihydrate-semi-hydrated wet-process phosphoric acid production process' disclosed in the patent CN107840317A, the invention has the advantages that: the invention can make full use of free sulfate radical (SO)4 2-) Promoting crystallization conversion and dilution heat thereof, and does not affect the sulfate radical (SO) of the finished phosphoric acid4 2-) And (4) content. The adding amount of the concentrated sulfuric acid in the crystal transfer tank is increased by 10 percent compared with that in the comparison file, so that more concentrated sulfuric acid supplies dilution heat to the crystal transfer tank for crystal transfer processDissolving in liquid phase of converted slurry, filtering, and adding free sulfate radical (SO)4 2-) Returning to the reaction tank with the diluted phosphoric acid to participate in the decomposition of the phosphorite to obtain CaSO4·2H2And (4) O crystallization. In the comparison document, because of the crystal transformation requirement, the addition amount of concentrated sulfuric acid accounts for 70% of the total amount of the concentrated sulfuric acid, the utilization of the dilution heat of the sulfuric acid is lower than that of the invention, if the temperature of the crystal transformation tank does not reach the required 100-104 ℃, the temperature of the crystal transformation tank needs to be improved by other heat exchange means, and the energy consumption is correspondingly increased; in addition, the crystal transition tank has free sulfate radical (SO)4 2-) Reaching 160-180g/L, filtering and separating to obtain medium concentration phosphoric acid, wherein one part is finished phosphoric acid containing sulfate radical (SO)4 2-) Up to 160-180g/L, and the mass ratio thereof is up to 6% or even higher, which is not beneficial to the downstream industrial product production from the view point of wet-process phosphoric acid application. The invention adopts two-step filtration, and sulfate radical (SO) is dissociated from a decomposition tank4 2-) The concentration determines the sulfate radical content (0.5-1.5%) of the finished product phosphoric acid, namely the finished product phosphoric acid obtained by the invention has lower sulfate radical content.
Drawings
FIG. 1 is a process flow diagram of the present invention.
FIG. 2 shows α -CaSO obtained by mixing upper layer slurry and bottom layer slurry, filtering and washing41/2 crystallization pattern.
FIG. 3 shows α -CaSO obtained after filtering and washing the middle layer slurry41/2 crystallization pattern.
Detailed Description
The technical scheme of the invention is more specifically explained by combining the following embodiments:
the components of the phosphorite, the phosphoric acid and the phosphogypsum are actual inspection data, and the invention is subjected to 1.5tP2O5And/h, verifying a wet-process phosphoric acid process pilot plant. After ore blending, two phosphorite ores with different nutrients in the table 1 are obtained as raw materials, and the industrial pilot test of the scale is carried out.
Compared with two ore blending methods, 2# phosphorite P2O5The components are low, so in the method, the concentration of the finished product phosphoric acid obtained from the 2# phosphorite product is correspondingly low; and the impurity content is especiallyThe quality of gypsum is reduced due to the fact that the content of acid insoluble substances is high, but the main economic index of the gypsum produced by the method is not greatly influenced.
TABLE 1 analysis of phosphate slurry (dry basis)
Example 1
Step 1, grinding the No. 1 phosphate rock described in Table 1 into a pulp of phosphorus ore (30 wt.% H)2O) and 98 wt.% concentrated sulfuric acid were continuously added to the decomposer at 7.1t/h and 0.8t/h, respectively, while omega (P) from the semi-water filtration process was added2O5)32.7 wt.% of dilute phosphoric acid and primary washing liquid mixed solution are subjected to phosphorite decomposition reaction, wherein phosphorite slurry is converted into dry base, and 98 wt.% of concentrated sulfuric acid is converted into pure H2SO4Conversion of dilute phosphoric acid to P2O5The mass ratio of the last three is 1:0.16:1.6, the technological indexes of the decomposer are controlled as follows: the temperature is 80-85 ℃; free sulfate ion (SO)4 2-) The concentration is 10-20 g/L; slurry solids 25 wt.%; the reaction time is 2.5 to 3 hours, and the phosphorite decomposition mixed slurry is obtained.
Step 2, carrying out solid-liquid separation on the mixed slurry (47 wt.%) in the step 1 by a filtering process according to the amount of 13.7t/h to obtain 3.5t/h product phosphoric acid (P)2O5Concentration 42 wt.% (see table 2) and by-product phosphogypsum dihydrate (main component CaSO)4·2H2O), conveying the dihydrate phosphogypsum to a crystal transferring tank directly without washing. The other 53 wt.% of the mixed slurry in step 1 was directly transferred to the hemihydrate trough to take part in the conversion, recrystallization.
Analysis of finished phosphoric acid from phosphate rock product # Table 21
And 3, adding the slurry from the step 1 and the dihydrate phosphogypsum from the step 2 into a crystal conversion tank, and simultaneously continuously adding 98 wt.% of concentrated sulfuric acid (the acid-mineral ratio is 0.64) into the crystal conversion tank at 3.22t/h for conversion and recrystallization. Controlling the conversion temperature of the process index of the crystal conversion tank to be 100-104.5 ℃,controlling slurry solids content 23 wt.%, free sulfate ion (SO)4 2-) The concentration is 160-180g/L, and the conversion reaction time is designed to be 1.5-2 h. CaSO4·2H2O conversion and recrystallization to form α -CaSO4·0.5H2O to obtain semi-water conversion mixed slurry, wherein the phosphogypsum is α -CaSO4·0.5H2O, the shape of which is hexagonal prism.
And 4, carrying out three-stage cyclone separation on the mixed slurry of the semi-water crystal converter tank, wherein the three-stage cyclone separation aims at separating and filtering the slurry according to the solid phase components and the sedimentation rate difference of the slurry, the slurry passing through the three-stage cyclone is divided into an upper layer, a middle layer and a lower layer, and the slurry of the upper layer and the slurry of the lower layer are converged.
The confluence slurry and the middle layer slurry are respectively fed into two different filters for filtration and separation, and the filtered filtrate is mixed with a primary washing solution to obtain 32.73 wt.% of P2O5The diluted phosphoric acid is sent to a decomposition tank to participate in the decomposition of phosphorite, and the filtered filter cake is α semi-hydrated phosphogypsum (α -CaSO)4·0.5H2O), three countercurrent washes with hot wastewater at 70 ℃.
And 5, metering the neutralized and washed phosphogypsum by using an 8% quicklime (90 wt.% CaO) solution to respectively obtain α by-products of semi-hydrated phosphogypsum shown in the table 3, and respectively piling and using the two parts of gypsum.
Analysis of byproduct phosphogypsum of phosphate rock in Table 31
The numbers 1 and 2 respectively correspond to the middle layer and the interflow slurry filter gypsum, and are respectively suitable for high-strength gypsum powder and cement retarder production raw materials.
Example 2
Step 1, grinding the 2# phosphate rock described in Table 1 into a phosphate pulp (30 wt.% H)2O) and 98 wt.% concentrated sulfuric acid were continuously added to the decomposer at 8.6t/h and 2.1t/h, respectively, while omega (P) from the semi-water filtration process was added2O5)28 wt.% of diluted phosphoric acid and primary washing liquid mixed solution are subjected to phosphorite decomposition reaction, wherein the phosphorite slurry is converted into dry base and 9 percent of primary washing liquidConversion of 8 wt.% concentrated sulfuric acid to H2SO4Conversion of dilute phosphoric acid to P2O5The mass ratio of the last three is 1:0.32:1.3, the technological indexes of the decomposer are controlled as follows: the temperature is 80-85 ℃; free sulfate radical (SO)4 2-) The concentration is 10-20 g/L; slurry solids 25 wt.%; the reaction time is 2.5 to 3 hours, and the phosphorite decomposition mixed slurry is obtained.
Step 2, carrying out solid-liquid separation on the mixed slurry (47 wt.%) in the step 1 by a filtering process according to the amount of 17.2t/h to obtain 4.4t/h product phosphoric acid (P)2O535 wt.% (see table 4) and by-product phosphogypsum dihydrate (main component CaSO)4·2H2O), conveying the dihydrate phosphogypsum to a crystal transferring tank directly without washing. The other 53 wt.% of the mixed slurry in step 1 was directly transferred to the hemihydrate trough to take part in the conversion, recrystallization.
Analysis of finished phosphoric acid obtained from phosphate rock product # Table 42
And 3, adding the slurry from the step 1 and the dihydrate phosphogypsum from the step 2 into a crystal conversion tank, and simultaneously continuously adding 98 wt.% of concentrated sulfuric acid (the acid-mineral ratio is 0.56) at 3.05t/h for conversion and recrystallization. Controlling the conversion temperature of the process index of the crystal conversion tank to be 100-104.5 ℃, controlling the solid content of slurry to be 21 wt.%, and controlling free sulfate ions (SO)4 2-) The concentration is 160-180g/L, and the conversion reaction time is designed to be 1.5-2 h. CaSO4·2H2O conversion and recrystallization to form α -CaSO4·0.5H2O to obtain semi-water conversion mixed slurry, wherein the phosphogypsum is α -CaSO4·0.5H2O, the shape of which is hexagonal prism.
And 4, carrying out three-stage cyclone separation on the mixed slurry of the semi-water crystal converter tank, wherein the three-stage cyclone separation aims at separating and filtering the slurry according to the solid phase components and the sedimentation rate difference of the slurry, the slurry passing through the three-stage cyclone is divided into an upper layer, a middle layer and a lower layer, and the slurry of the upper layer and the slurry of the lower layer are converged.
The interflow slurry and the middle slurry are filtered separately in two different filters and passed throughThe filtrate was mixed with a first wash to give 27.2 wt.% P2O5The diluted phosphoric acid is mixed and sent to a decomposition tank to participate in the decomposition of phosphorite, and the filtered filter cake is α semi-hydrated phosphogypsum (α -CaSO)4·0.5H2O), three countercurrent washes with hot wastewater at 70 ℃.
And 5, metering the neutralized and washed phosphogypsum by using 8% of quicklime (90 wt% of CaO) solution to respectively obtain α by-products of semi-hydrated phosphogypsum shown in the table 5, and respectively piling and using two parts of gypsum.
TABLE 52 phosphorus ore by-product phosphogypsum analysis
The numbers 1 and 2 respectively correspond to the middle layer and the interflow slurry filter gypsum, and are respectively suitable for high-strength gypsum powder and cement retarder production raw materials.
Claims (2)
1. A method for producing wet-process phosphoric acid and α semi-hydrated phosphogypsum from medium-grade phosphorite is characterized by comprising the following steps:
step 1, decomposition reaction: adding 98 wt.% of concentrated sulfuric acid and 28-32 wt.% of phosphate ore slurry into a reaction tank, and simultaneously adding the dilute phosphoric acid in the subsequent step 4 to perform phosphate ore decomposition reaction, wherein the phosphate ore slurry is converted into dry basis, and the 98 wt.% of concentrated sulfuric acid is converted into pure H2SO4Conversion of dilute phosphoric acid to P2O5The mass ratio of the last three is 1 (0.16-0.32) to 1.3-1.6; controlling the temperature of the reaction tank to be 80-85 ℃, the reaction time to be 2.5-3 hours, and the reaction tank reaching the relative equilibrium state process index: free sulfate ion (SO)4 2-) The concentration is 10-20g/L, and the solid content of the mixed slurry is 24-26 wt.%;
step 2, solid-liquid separation: dividing the mixed slurry in the reaction tank into a first group of slurry and a second group of slurry, wherein the first group of slurry accounts for 44-50 wt% of the mixed slurry of the phosphorite decomposition reaction, and performing solid-liquid separation on the first group of slurry to obtain the phosphogypsum dihydrate (CaSO)4·2H2O) and finished phosphoric acid;
step 3, semi-water conversion reaction: mixing the second componentPhosphogypsum dihydrate (CaSO)4·2H2O) is added into a crystal transformation tank, and 98 wt.% of concentrated sulfuric acid is added for semi-water transformation reaction, so that the phosphogypsum dihydrate (CaSO)4·2H2O) to α phosphogypsum hemihydrate (α -CaSO)4·0.5H2O), wherein the phosphate ore slurry is converted to dry basis and 98 wt.% of concentrated sulfuric acid added in the semi-water conversion reaction is converted to pure H2SO4The mass ratio of the two is 1 (0.48-0.64); the temperature of the crystal conversion tank is 100-104.5 ℃, the reaction time is 1.5-2 hours, and the crystal conversion tank reaches the relative equilibrium state process indexes: free sulfate ion (SO 4)2-) The concentration is 160-180g/L, and the solid content of the slurry is controlled to be 21-23 wt% by adding dilute phosphoric acid in the subsequent step 4;
and 4, filtering and washing, namely performing three-stage cyclone separation on the slurry in the crystal conversion tank, mixing the slurry of the upper layer and the slurry of the bottom layer obtained after the three-stage cyclone separation, filtering and washing, and independently filtering and washing the slurry of the middle layer to obtain α semi-hydrated phosphogypsum and diluted phosphoric acid used for returning to the step 1 and the step 3.
2. The method for producing wet-process phosphoric acid and α phosphogypsum hemihydrate from medium-grade phosphate ores as set forth in claim 1, characterized in that the method further comprises:
and 5, neutralizing: by using Ca (OH)2Mixing the α phosphogypsum hemihydrate (α -CaSO)4·0.5H2O) to pH 7-8.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811022775.3A CN109292744B (en) | 2018-09-04 | 2018-09-04 | Method for producing wet-process phosphoric acid and α semi-hydrated phosphogypsum from medium-grade phosphate ore |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811022775.3A CN109292744B (en) | 2018-09-04 | 2018-09-04 | Method for producing wet-process phosphoric acid and α semi-hydrated phosphogypsum from medium-grade phosphate ore |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109292744A CN109292744A (en) | 2019-02-01 |
| CN109292744B true CN109292744B (en) | 2020-03-17 |
Family
ID=65166243
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811022775.3A Active CN109292744B (en) | 2018-09-04 | 2018-09-04 | Method for producing wet-process phosphoric acid and α semi-hydrated phosphogypsum from medium-grade phosphate ore |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109292744B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110316708A (en) * | 2019-06-06 | 2019-10-11 | 贵州川恒化工股份有限公司 | The method that phosphorus ore produces half water phosphoric acid coproduction alpha type high-strength gypsum |
| CN110482920B (en) * | 2019-09-04 | 2021-08-10 | 昆明川金诺化工股份有限公司 | Method for purifying flotation phosphorus tailings and preparing concrete building blocks |
| CN112191361B (en) * | 2020-09-27 | 2022-06-21 | 湖北祥云(集团)化工股份有限公司 | Method and production system for preparing powdered ammonium and high-quality ammonium phosphate by phosphorite classification |
| CN113120875B (en) * | 2021-04-25 | 2022-12-30 | 云南云天化股份有限公司 | Production method of low-impurity wet-process phosphoric acid and high-quality alpha-hemihydrate gypsum |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102001636A (en) * | 2010-09-26 | 2011-04-06 | 四川大学 | Method for producing broad-concentration phosphoric acid and clean plaster by middle-low grade phosphorus ore wet process |
| CN105948009A (en) * | 2016-04-28 | 2016-09-21 | 昆明川金诺化工股份有限公司 | Energy-saving semihydrate-dihydrate wet-process phosphoric acid and white gypsum coproduction method |
| CN107840317A (en) * | 2017-10-30 | 2018-03-27 | 安徽六国化工股份有限公司 | A kind of water wet method phosphoric acid manufacture process of two water of one-step method half |
| CN107840316A (en) * | 2017-10-30 | 2018-03-27 | 安徽六国化工股份有限公司 | A kind of two step method dihydrate wet phosphoric acid production technology |
| CN109020282A (en) * | 2018-09-04 | 2018-12-18 | 安徽六国化工股份有限公司 | The method that middle-low grade phosphate produces phosphoric acid by wet process and half water ardealite of α |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103086335B (en) * | 2013-02-05 | 2014-06-18 | 瓮福（集团）有限责任公司 | Method for production of phosphoric acid and combined production of a-hemihydrate gypsum through dehydrate-hemihydrate wet phosphoric acid technology |
| CN103213960A (en) * | 2013-05-17 | 2013-07-24 | 成都川科化工有限公司 | Method for producing phosphoric acid by decomposing low-grade phosphate rock with wet-process phosphoric acid |
| CN103435021A (en) * | 2013-08-19 | 2013-12-11 | 瓮福（集团）有限责任公司 | Wet process phosphoric acid production device and method |
| TN2014000010A1 (en) * | 2014-01-08 | 2015-07-01 | Groupe Chimique Tunisien | METHOD FOR MANUFACTURING WET-ROAD PHOSPHORIC ACID AND REACTIONAL AND FILTRATION DEVICES RELATED TO THE PROCESS |
| CN106044730B (en) * | 2016-06-03 | 2018-05-18 | 四川宏达股份有限公司 | Utilize the method for high-grade phosphorus ore production phosphoric acid by wet process |
-
2018
- 2018-09-04 CN CN201811022775.3A patent/CN109292744B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102001636A (en) * | 2010-09-26 | 2011-04-06 | 四川大学 | Method for producing broad-concentration phosphoric acid and clean plaster by middle-low grade phosphorus ore wet process |
| CN105948009A (en) * | 2016-04-28 | 2016-09-21 | 昆明川金诺化工股份有限公司 | Energy-saving semihydrate-dihydrate wet-process phosphoric acid and white gypsum coproduction method |
| CN107840317A (en) * | 2017-10-30 | 2018-03-27 | 安徽六国化工股份有限公司 | A kind of water wet method phosphoric acid manufacture process of two water of one-step method half |
| CN107840316A (en) * | 2017-10-30 | 2018-03-27 | 安徽六国化工股份有限公司 | A kind of two step method dihydrate wet phosphoric acid production technology |
| CN109020282A (en) * | 2018-09-04 | 2018-12-18 | 安徽六国化工股份有限公司 | The method that middle-low grade phosphate produces phosphoric acid by wet process and half water ardealite of α |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109292744A (en) | 2019-02-01 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109292744B (en) | Method for producing wet-process phosphoric acid and α semi-hydrated phosphogypsum from medium-grade phosphate ore | |
| WO2017045520A1 (en) | Method for producing phosphoric acid and by-producing alpha-hemihydrate gypsum by wet-process | |
| CN101607834B (en) | Preparation method for preparing potash fertilizer and producing sulfuric acid simultaneously employing mineral with potassium, ardealite and high-sulphur coal | |
| CN105948009B (en) | A kind of method for saving the half white gypsum of water dihydrate wet phosphoric acid coproduction | |
| CN109020282B (en) | The method that middle-low grade phosphate produces phosphoric acid by wet process and half water ardealite of α | |
| CN100494051C (en) | Technology for preparing fine calcium phosphate using phosphor-gypsum backwater and its wash liquid | |
| CN101993256B (en) | Method for preparing agricultural potassium sulfate from potassium-rich rock | |
| CN109290060A (en) | A kind of process for subsequent treatment and phosphate ore floatation method of phosphate ore flotation tailings | |
| CN112850674B (en) | Production device and method for co-producing alpha-hemihydrate gypsum by two-step wet-process phosphoric acid | |
| CN102001636A (en) | Method for producing broad-concentration phosphoric acid and clean plaster by middle-low grade phosphorus ore wet process | |
| CN105367176A (en) | Multi-element comprehensive utilization process for phosphorus-potassium associated ore | |
| CN107419335A (en) | The method that hydrochloric acid method Cycle-decomposition ardealite and phosphorus mine tailing prepare calcium sulfate crystal whiskers | |
| CN105776303A (en) | Production method of alpha-hemihydrate gypsum | |
| CN111392702B (en) | Method for preparing concentrated phosphoric acid and gypsum powder by semi-hydrated dihydrate process | |
| CN107879321B (en) | Method for demagging phosphate rock and co-producing sodium fluosilicate and magnesium sulfate | |
| CN1517301A (en) | Method of preparing election class potassium carbonate using potassium rich rock | |
| CN105350066A (en) | Method for preparing calcium sulfate hemihydrate crystal whisker by ardealite | |
| CN113443614A (en) | Method for converting calcium sulfate dihydrate into alpha-calcium sulfate hemihydrate in dihydrate-hemihydrate wet-process phosphoric acid leaching process | |
| CN107827114B (en) | Method for recovering phosphorus in wet-process phosphoric acid concentrated slag acid and co-producing dihydrate gypsum and sodium fluosilicate | |
| CN105384157A (en) | Technology for producing phosphoric acid through half-hydrate-dihydrate method | |
| CN102674405A (en) | Method for preparing potassium sulfate by using picromerite | |
| CN111732086A (en) | Process for preparing phosphoric acid and co-producing high-purity gypsum by semi-water-dihydrate method | |
| CN107381525A (en) | Utilize the technique and device of mid-low grade collophanite ore production industrial monoammonium phosphate coproduction high-quality MAP | |
| CN116768170A (en) | Method for preparing phosphoric acid and derivatives thereof by using phosphorite | |
| CN113148968B (en) | Method for producing alpha-semi-hydrated gypsum by wet-process phosphorus processing |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| CB03 | Change of inventor or designer information |
Inventor after: Ma Jian Inventor after: Zhang Jun Inventor after: Liu Qing Inventor after: Zheng Zhiyin Inventor after: Shen Hao Inventor after: Zhu Yingjun Inventor after: Yang Baozhang Inventor after: Lei Yun Inventor after: Liu Rong Inventor after: Chen Ming Inventor after: Peng Kerong Inventor before: Zheng Zhiyin Inventor before: Liu Qing Inventor before: Shen Hao Inventor before: Zhu Yingjun Inventor before: Yang Baozhang Inventor before: Lei Yun Inventor before: Liu Rong Inventor before: Chen Ming Inventor before: Peng Kerong Inventor before: Zhang Jun |
|
| CB03 | Change of inventor or designer information | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |