CN112030222A - Method for preparing calcium sulfate whisker by using calcium-removing resin eluent - Google Patents
Method for preparing calcium sulfate whisker by using calcium-removing resin eluent Download PDFInfo
- Publication number
- CN112030222A CN112030222A CN202010896680.5A CN202010896680A CN112030222A CN 112030222 A CN112030222 A CN 112030222A CN 202010896680 A CN202010896680 A CN 202010896680A CN 112030222 A CN112030222 A CN 112030222A
- Authority
- CN
- China
- Prior art keywords
- calcium
- hydrochloric acid
- solution
- eluent
- resin
- 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.)
- Pending
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B7/00—Single-crystal growth from solutions using solvents which are liquid at normal temperature, e.g. aqueous solutions
- C30B7/10—Single-crystal growth from solutions using solvents which are liquid at normal temperature, e.g. aqueous solutions by application of pressure, e.g. hydrothermal processes
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B28/00—Production of homogeneous polycrystalline material with defined structure
- C30B28/04—Production of homogeneous polycrystalline material with defined structure from liquids
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
- C30B29/10—Inorganic compounds or compositions
- C30B29/46—Sulfur-, selenium- or tellurium-containing compounds
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
- C30B29/60—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape characterised by shape
- C30B29/62—Whiskers or needles
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Crystallography & Structural Chemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
Abstract
The invention provides a method for preparing calcium sulfate whiskers by using a calcium-removing resin eluent, which comprises the following steps: (1) evaporating and concentrating the calcium-removed resin eluent to obtain a concentrated solution, adding a sulfuric acid solution into the concentrated solution for precipitation reaction, standing the reaction solution, and cooling to 20-25 ℃; wherein the molar ratio of calcium ions in the concentrated solution to sulfuric acid in the sulfuric acid solution is 1 (1.1-1.8); (2) carrying out solid-liquid separation on the reaction liquid and washing to obtain a calcium sulfate filter cake; (3) preparing suspension with calcium sulfate concentration of 1-2mol/L by using the filter cake, and crystallizing and aging the suspension; (4) and carrying out solid-liquid separation on the aged feed liquid, and washing a filter cake obtained by the solid-liquid separation with water to obtain calcium sulfate dihydrate crystal whiskers. The invention provides a method for preparing calcium sulfate whiskers by using a calcium removal resin eluent.
Description
Technical Field
The invention relates to a method for preparing calcium sulfate whiskers, in particular to a method for preparing calcium sulfate whiskers by using a calcium removal resin eluent.
Background
The high-alumina fly ash produced by Shenhua quasi-Geer energy limited company adopts a one-step acid dissolution method to produce alumina, calcium ions in feed liquid can be removed through ion exchange resin in the extraction process, and the calcium ions are enriched in calcium-removing resin eluent, so that the high-alumina fly ash has high extraction value. Aiming at calcium-removing eluent, the prior art adopts alkali neutralization, and neutralization precipitation is common solid waste to be subjected to landfill treatment, thereby causing resource waste.
The pH of the calcium-removing resin eluent is about 1.0, the main components of the calcium-removing resin eluent are shown in Table 1, the calcium-removing resin eluent mainly contains calcium chloride and aluminum chloride, and a small amount of magnesium, so that the direct discharge seriously affects the environment, and therefore, the calcium-removing resin eluent needs to be subjected to harmless treatment or comprehensive utilization.
TABLE 1 resin eluent principal Components
| Composition (I) | Ca2+ | Al3+ | Mg2+ | Cl- |
| Content (mg/L) | 21457-43239 | 7560-16400 | 1610-8510 | 91402-186200 |
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a method for preparing calcium sulfate whiskers by using a calcium removal resin eluent.
In order to realize the purpose of the invention, the invention adopts the following technical scheme:
a method for preparing calcium sulfate whiskers by using a calcium removal resin eluent comprises the following steps:
(1) evaporating and concentrating the calcium-removed resin eluent to obtain a concentrated solution, adding a sulfuric acid solution into the concentrated solution for precipitation reaction, standing the reaction solution, and cooling to 20-25 ℃;
wherein the molar ratio of calcium ions in the concentrated solution to sulfuric acid in the sulfuric acid solution is 1 (1.1-1.8), preferably 1 (1.2-1.6), such as 1:1.3 and 1: 1.5;
(2) carrying out solid-liquid separation on the reaction liquid and washing to obtain a calcium sulfate filter cake;
(3) preparing suspension with calcium sulfate concentration of 1-2mol/L by using the filter cake, and crystallizing and aging the suspension;
(4) and carrying out solid-liquid separation on the aged feed liquid, and washing a filter cake obtained by the solid-liquid separation with water to obtain calcium sulfate dihydrate crystal whiskers.
The calcium-removing resin eluent in the step (1) is an eluent obtained by desorbing an aluminum chloride solution containing calcium ions by using an eluent after the aluminum chloride solution is adsorbed by the calcium-removing resin; for example, waste calcium-containing regeneration liquid obtained in patent application CN 107628633B.
In one embodiment, the calcium removal resin eluent can be obtained by the following method:
a. crushing the fly ash to be less than 100 meshes, carrying out wet magnetic separation to remove iron so as to reduce the content of iron oxide in the fly ash to be less than 1.0 wt%, then adding a hydrochloric acid solution into the fly ash for reaction and carrying out solid-liquid separation so as to obtain a hydrochloric acid leaching solution with the pH value of 1-3;
b. introducing the hydrochloric acid immersion liquid into an anion resin column for iron adsorption to obtain iron-removed hydrochloric acid immersion liquid;
c. introducing the hydrochloric acid leaching solution subjected to iron removal into a chelating resin column for calcium adsorption, and eluting with water or hydrochloric acid as an eluent after adsorption saturation to obtain a calcium-removal resin eluent;
preferably, the concentration of the hydrochloric acid in the step a is selected from 20-37 wt%, and the molar ratio of HCl in the hydrochloric acid to alumina in the fly ash is 4:1-9: 1;
preferably, the step of passing the hydrochloric acid leaching solution into an anion resin column in the step b comprises the following steps: passing the hydrochloric acid extract through an anion resin column from bottom to top at 60-90 deg.C, wherein the flow rate of the hydrochloric acid extract is 3-4 times of resin volume/hr; in some embodiments, the anion resin column can be selected from the group consisting of gel-type strongly basic anion exchange resins, gel-type weakly basic anion exchange resins, macroporous strongly basic anion exchange resins, and macroporous weakly basic anion exchange resins; wherein the resin can be selected from gel type strongly basic anion exchange resin with the resin brand of 201 × 7 or FPA40 Cl; can be selected from gel type weak base anion exchange resin with resin brand LX-67 or FPA 55B; can be selected from macroporous strongly basic anion exchange resin with resin brand D202, D201, FPA98Cl or FPA91 Cl; can be selected from macroporous weakly basic anion exchange resins with resin designation D301, FPA51 or D938.
Preferably, the step of introducing the hydrochloric acid leaching solution into the chelating resin column in the step c comprises the following steps: and (3) passing the hydrochloric acid immersion liquid through a resin column from bottom to top at the temperature of 20-90 ℃, wherein the flow rate of the hydrochloric acid immersion liquid is 1-4 times of the volume of the resin per hour.
In some preferred embodiments, the concentration of the hydrochloric acid in step a is selected from 20 to 37 wt%, and the molar ratio of HCl in the hydrochloric acid to alumina in the fly ash is 4:1 to 9:1, such as 5:1, 6: 1; more preferably, the reaction is carried out for 0.5 to 4.0 hours after adding the hydrochloric acid solution into the fly ash in the step a.
In some preferred embodiments, the step of passing the hydrochloric acid leaching solution into an anionic resin column in step b is: passing the hydrochloric acid extract through an anion resin column from bottom to top at 60-90 deg.C, wherein the flow rate of the hydrochloric acid extract is 3-4 times of resin volume/hr.
In some preferred embodiments, the step of passing the hydrochloric acid leaching solution into the chelating resin column in step c comprises: passing the hydrochloric acid extract through a resin column from bottom to top at 20-90 deg.C, wherein the flow rate of the hydrochloric acid extract is 1-4 times of resin volume/hr; specifically, the concentration of hydrochloric acid in step c is 2-10 wt%, and in the elution process, the elution temperature is 20-60 ℃, and the dosage of the eluent is 1-3 times of the volume of the resin. In some embodiments, the chelating resin column used in the present invention can be prepared by the method described in patent CN 107602750B.
The calcium-removing resin eluent comprises 20-43g/L Ca2+7.5-16g/L of Al3+1.6-8.5g/L of Mg2+90-180g/L Cl-(ii) a The pH value of the calcium-removing resin eluent is 1-3, such as 1.5 and 2.8; in some preferred embodiments, the calcium scavenging resin eluent comprises 28-38g/L Ca2+More preferably 30g/L or 32 g/L; 10-14 g-Al of L3+More preferably 12g/L or 13 g/L; 4.5-8.1g/L Mg2+More preferably 5g/L or 7 g/L; 120-160g/L Cl-More preferably 140g/L or 150 g/L; the pH value of the calcium-removing resin eluent is 1.5-2.5, such as 2, 2.2.
The calcium-removing resin eluent mentioned in the method can be concentrated and evaporated without pretreatment when in use.
In the step (1) of the preparation method, the calcium-removing resin eluent is evaporated and concentrated at 90-110 ℃ to help calcium ions form calcium sulfate precipitate in the subsequent step; in some embodiments, the concentrate is obtained by concentrating the calcium ion solution by evaporation to a concentration of 50g/L or more, preferably 60 to 90g/L, for example, 65g/L, 75g/L, 85 g/L.
In some preferred embodiments, a sulfuric acid solution is added to the above concentrate to perform a reaction at 60 to 80 ℃, e.g., 65 ℃, 70 ℃, wherein calcium ions and chloride ions are converted into calcium sulfate precipitate and hydrochloric acid; then standing the reaction solution, and cooling to 20-25 ℃ (namely room temperature) to further fully separate out calcium sulfate precipitate; specifically, when the calcium sulfate precipitate is not separated out any more, the reaction can be judged to be complete, and the next solid-liquid separation can be carried out; in some embodiments, the concentration of the sulfuric acid solution is preferably 80% to 95%, for example, 85% or 90% by mass.
In the step (2) of the preparation method of the present invention, the reaction solution after the reaction in the step (1) is subjected to solid-liquid separation, for example, a solid product can be separated by standing sedimentation, centrifugal sedimentation or other solid-liquid separation methods; the solid product after the solid-liquid separation is washed with water to remove impurities remaining on the surface thereof, and for example, the solid product can be washed with condensed water concentrated by evaporation in step (1).
In some specific embodiments, the filtrate obtained after the solid-liquid separation in step (2) is recycled to the preparation process of the calcium removal resin eluent, namely, the procedure of blending fly ash, water and hydrochloric acid in the process of producing alumina by fly ash by a one-step acid dissolution method, and the recycling of the filtrate can be used for recovering H introduced by a sulfuric acid solution+And residual SO of reaction4 2-. In some preferred embodiments, the present inventors have found that the molar ratio of sulfuric acid in the sulfuric acid solution added in step (1) to calcium ions in the concentrate is 1 (1.1-1.8), and that reasonable control of SO in the filtrate can be achieved4 2-The residual amount of ions.
In the step (3) of the preparation method of the present invention, the filter cake obtained by solid-liquid separation in the step (2) is prepared into a suspension with a calcium sulfate concentration of 1 to 2mol/L by using water, and further preferably, the suspension is subjected to ultrasonic treatment at room temperature, for example, at 20 ℃ and 25 ℃ for 3 to 5min, so that the suspension is uniformly dispersed.
In a specific embodiment of the present invention, in the step (3), the suspension is subjected to crystallization reaction at 80 to 120 ℃, for example, 90 ℃, 100 ℃, 110 ℃; in some embodiments of the invention, the crystallization reaction is carried out after adding a crystal growth promoter to the suspension; in some specific crystallization reaction processes, the suspension is placed in a closed crystallization reaction kettle for crystallization reaction, the pressure of the crystallization reaction temperature can be controlled to be 0-0.2MPa, and the crystallization reaction is preferably carried out for 2-4 hours; standing and aging the reaction liquid obtained by the crystallization reaction for 1-4 h; wherein the concentration of the crystal growth substance added to the suspension is 1-5g/ml, such as 2g/ml, 3g/ml, 4 g/ml.
In the present invention, the crystal growth substance may be selected from one or more of calcium sulfate seed crystals, sodium lauryl sulfate, copper sulfate, ethylene glycol or triethylene glycol.
As is well known to those skilled in the art, calcium sulfate whiskers can be classified into calcium sulfate dihydrate whiskers, calcium sulfate hemihydrate whiskers and calcium sulfate anhydrite whiskers according to the content of crystal water, and in step (4) of the preparation method of the present invention, the calcium sulfate dihydrate whiskers are dried at a temperature of 120-.
By adopting the technical scheme, the method has the following technical effects:
aiming at the process of producing alumina by fly ash through a one-step acid dissolution method, calcium-removed resin eluent obtained by an impurity removal procedure is evaporated and concentrated, an excessive sulfuric acid solution is added and cooled to room temperature, calcium sulfate precipitate is fully separated out, calcium ions and impurity elements are separated, and a calcium sulfate whisker product with the content of more than 98 percent and the length-diameter ratio of the calcium sulfate whisker of 50 is prepared after further treatment, and completely meets the quality index of the calcium sulfate whisker; the recovery of calcium ions is improved, and simultaneously, the residual quantity of SO 42-ions in the filtrate is reduced, SO that the obtained calcium sulfate whisker product has white appearance and no impurities.
The method changes the calcium-removing resin eluent into valuable, and has important significance for the perfection of the fly ash comprehensive utilization recycling economy industrial chain.
Drawings
FIG. 1: a flow chart of a specific embodiment of the process for preparing calcium sulfate whiskers by using the method of the invention;
mixing fly ash, concentrated hydrochloric acid and water, blending, dissolving out, performing solid-liquid separation to obtain hydrochloric acid immersion liquid, performing impurity removal (namely removing impurities by using iron resin and calcium resin) to obtain effluent liquid, and performing evaporation crystallization and calcination to the effluent liquid to obtain an aluminum oxide product; evaporating and concentrating the calcium-removed resin eluent obtained in the impurity removal process, adding a concentrated sulfuric acid solution into the eluent, carrying out solid-liquid separation after reaction, recycling the obtained filtrate (namely hydrochloric acid) to the batching process, and preparing the obtained filter cake into a calcium sulfate suspension; and (3) adding a crystal growth substance to perform crystallization and aging treatment after ultrasonic uniform mixing, and drying a filter cake after solid-liquid separation of the obtained feed liquid to obtain the calcium sulfate hemihydrate crystal whisker.
Detailed Description
In order to better understand the present invention, the following examples are provided to further illustrate the content of the present invention.
The following methods were used in the following examples:
the quality detection method of the calcium sulfate whisker comprises the following steps: test detection method specified in calcium sulfate whisker (DB 43/T1155-2015) which is a local standard in Hunan province.
The following examples provide information on the source of the raw materials and the equipment:
(1) calcium removal resin eluent:
a. the fly ash is crushed to be below 100 meshes, and the content of ferric oxide in the fly ash is reduced to be below 0.8 wt% after wet magnetic separation is carried out by using a vertical ring magnetic separator for removing iron from the fly ash. Putting the filter cake after magnetic separation into an acid-resistant reaction kettle, adding 37 wt% industrial hydrochloric acid to perform acid-soluble reaction, wherein the molar ratio of HCl in the hydrochloric acid to alumina in the fly ash is 4.5: 1; the reaction temperature is 200 ℃, the reaction pressure is 2.1MPa, and the reaction time is 1 hour; filter pressing and washing the reaction product by a plate and basket filter press to obtain hydrochloric acid leaching solution with the pH value of 1.7;
b. passing the hydrochloric acid extract through an anion resin column from bottom to top at 70 deg.C, wherein the flow rate of the hydrochloric acid extract is 2 times of resin volume/hr, to obtain iron-removed hydrochloric acid extract;
c. introducing the hydrochloric acid immersion liquid into a chelating resin column for calcium adsorption, eluting with 4 wt% hydrochloric acid as an eluent at 25 ℃ after adsorption saturation, wherein the flow rate of the eluent is 2 times of the resin volume/hour, and eluting with 2 times of the resin volume to obtain a decalcified resin eluent, wherein the main components of the decalcified resin eluent are shown in Table 1 below;
TABLE 1
| Composition (I) | Ca2+ | Al3+ | Mg2+ | Cl- |
| Content (g/L) | 32 | 12 | 6.8 | 139 |
(2) Calcium sulfate seed crystal: chemical purity;
other chemical reagents used in the method of the invention all adopt reagents which are conventional in the field, and the purity is more than chemical purity.
Example 1
(1) Evaporating and concentrating 1L of calcium-removing resin eluent at 100 deg.C until the concentration of calcium ion is 50g/L to obtain concentrated solution; continuing to add 69.7g of concentrated sulfuric acid solution with the mass percentage concentration of 95% into the concentrated solution, wherein the molar ratio of calcium ions in the concentrated solution to sulfuric acid in the added sulfuric acid solution is 1: 1.5; then standing and cooling to 20 ℃ after complete reaction at 60 ℃;
(2) carrying out solid-liquid separation on the reaction liquid in the step (1), and washing a filter cake obtained by twice solid-liquid separation by using evaporation condensed water;
(3) adding water into the filter cake to prepare suspension with calcium sulfate concentration of 1.5mol/L, and performing ultrasonic treatment at room temperature (20 ℃) for 3min to make the suspension uniform; then putting the suspension into a crystallization reaction kettle, adding sodium dodecyl sulfate, and performing crystallization reaction for 3 hours at 90 ℃; standing and aging a reaction liquid obtained by crystallization reaction for 2 hours;
(4) and (3) carrying out solid-liquid separation on the aged feed liquid, washing a filter cake obtained by the solid-liquid separation with water to obtain calcium sulfate dihydrate crystal whiskers, and drying at 150 ℃ to obtain the calcium sulfate hemihydrate crystal whiskers.
The quality index of the calcium sulfate hemihydrate whiskers obtained in example 1 is shown in table 2 below.
TABLE 2 quality index of calcium sulfate hemihydrate whiskers
Example 2
(1) 1L of calcium-removing resin eluent is taken to be evaporated and concentrated under the condition of 100 ℃ until the concentration of calcium ions is 78g/L, and concentrated solution is obtained; 60.41g of concentrated sulfuric acid solution with the mass percentage concentration of 95% is continuously added into the concentrated solution, wherein the molar ratio of calcium ions in the concentrated solution to sulfuric acid in the added sulfuric acid solution is 1: 1.3; then standing and cooling to 25 ℃ after complete reaction at 60 ℃;
(2) carrying out solid-liquid separation on the reaction liquid in the step (1), and washing a filter cake obtained by twice solid-liquid separation by using evaporation condensed water;
(3) adding water into the filter cake to prepare suspension with calcium sulfate concentration of 1.5mol/L, and performing ultrasonic treatment at room temperature (20 ℃) for 3min to make the suspension uniform; then the suspension is put into a crystallization reaction kettle to carry out crystallization reaction for 3 hours at the temperature of 90 ℃; standing and aging a reaction liquid obtained by crystallization reaction for 2 hours;
(4) and (3) carrying out solid-liquid separation on the aged feed liquid, washing a filter cake obtained by the solid-liquid separation with water to obtain calcium sulfate dihydrate crystal whiskers, and drying at 150 ℃ to obtain the calcium sulfate hemihydrate crystal whiskers.
Example 3
(1) Evaporating and concentrating 1L of calcium-removing resin eluent at 100 deg.C until the concentration of calcium ion is 95g/L to obtain concentrated solution; continuing to add 69.7g of concentrated sulfuric acid solution with the mass percentage concentration of 95% into the concentrated solution, wherein the molar ratio of calcium ions in the concentrated solution to sulfuric acid in the added sulfuric acid solution is 1: 1.5; then standing and cooling to 22 ℃ after complete reaction at 60 ℃;
(2) carrying out solid-liquid separation on the reaction liquid in the step (1), and washing a filter cake obtained by twice solid-liquid separation by using evaporation condensed water;
(3) adding water into the filter cake to prepare suspension with calcium sulfate concentration of 1.5mol/L, and performing ultrasonic treatment at room temperature (20 ℃) for 3min to make the suspension uniform; then putting the suspension into a crystallization reaction kettle, carrying out crystallization reaction for 1h at 90 ℃, and standing and aging reaction liquid obtained by the crystallization reaction for 2 h;
(4) and (3) carrying out solid-liquid separation on the aged feed liquid, washing a filter cake obtained by the solid-liquid separation with water to obtain calcium sulfate dihydrate crystal whiskers, and drying at 150 ℃ to obtain the calcium sulfate hemihydrate crystal whiskers.
The quality indexes of the calcium sulfate hemihydrate whiskers obtained in examples 2 and 3 are shown in table 3 below.
TABLE 3
Comparative example 1
This comparative example differs from example 1 in that in step (1): adding 69.7g of concentrated sulfuric acid solution with the mass percentage concentration of 95% into the concentrated solution, wherein the molar ratio of calcium ions in the concentrated solution to sulfuric acid in the added sulfuric acid solution is 1: 1.5; and (3) directly carrying out solid-liquid separation in the step (2) on the hot reaction liquid after the reaction is completely carried out at 60 ℃.
Comparative example 2
This comparative example differs from example 1 in that in step (1): adding 44.14g of concentrated sulfuric acid solution with the mass percentage concentration of 95% into the concentrated solution, wherein the molar ratio of calcium ions in the concentrated solution to sulfuric acid in the added sulfuric acid solution is 1: 1; then the mixture is placed still and cooled to 20 ℃ after complete reaction at 60 ℃.
Comparative example 3
This comparative example differs from example 1 in that in step (1): adding 92.94g of concentrated sulfuric acid solution with the mass percentage concentration of 95% into the concentrated solution, wherein the molar ratio of calcium ions in the concentrated solution to sulfuric acid in the added sulfuric acid solution is 1: 2; then the mixture is placed still and cooled to 20 ℃ after complete reaction at 60 ℃.
Calcium ion recovery and residual SO in filtrate in example 1 and comparative examples 1-34 2-The residual levels are reported in table 4 below.
TABLE 4
| Index (I) | Example 1 | Comparative example 1 | Comparative example 2 | Comparative example 3 |
| Recovery ratio of calcium ion (%) | 92.31 | 46.59 | 64.98 | 93.54 |
| Residual SO in the filtrate4 2-(g/L) | 17.33 | 33.28 | 13.8 | 41.16 |
Claims (10)
1. A method for preparing calcium sulfate whiskers by using a calcium removal resin eluent is characterized by comprising the following steps:
(1) evaporating and concentrating the calcium-removed resin eluent to obtain a concentrated solution, adding a sulfuric acid solution into the concentrated solution for precipitation reaction, standing the reaction solution, and cooling to 20-25 ℃;
wherein the molar ratio of calcium ions in the concentrated solution to sulfuric acid in the sulfuric acid solution is 1 (1.1-1.8), preferably 1 (1.2-1.6);
(2) carrying out solid-liquid separation on the reaction liquid and washing to obtain a calcium sulfate filter cake;
(3) preparing suspension with calcium sulfate concentration of 1-2mol/L by using the filter cake, and crystallizing and aging the suspension;
(4) and carrying out solid-liquid separation on the aged feed liquid, and washing a filter cake obtained by the solid-liquid separation with water to obtain calcium sulfate dihydrate crystal whiskers.
2. The method of claim 1, wherein: in the step (1), the calcium-removing resin eluent is evaporated and concentrated at the temperature of 90-110 ℃ until the concentration of calcium ions is more than or equal to 50g/L, preferably 60-90g/L, so as to obtain the concentrated solution.
3. The method of claim 2, wherein: in the step (1), adding a sulfuric acid solution into the concentrated solution, reacting at 60-80 ℃, standing, and cooling to room temperature; the mass percentage concentration of the sulfuric acid solution is preferably 80-95%.
4. The method of claim 3, wherein: in the step (3), preparing the filter cake into 1-2mol/L suspension by using water; the suspension is preferably sonicated at room temperature for 3-5 min.
5. The method of claim 4, wherein: in the step (3), the suspension is subjected to crystallization reaction at the temperature of 80-120 ℃, and the crystallization reaction is preferably carried out for 2-4 h.
6. The method of claim 5, wherein: adding a crystal growth substance into the suspension, then carrying out the crystallization reaction, and standing and aging the reaction liquid after the crystallization reaction for 1-4 h;
wherein the concentration of the added crystal growth substance in the suspension is 1-5 g/ml; the crystal growth substance is preferably selected from one or more of calcium sulfate seed crystals, sodium lauryl sulfate, copper sulfate, ethylene glycol or triethylene glycol.
7. The method according to any one of claims 1-6, wherein: in the step (4), the calcium sulfate dihydrate whisker is dried for 2-3h at the temperature of 120-200 ℃ to obtain the calcium sulfate hemihydrate whisker.
8. The method according to any one of claims 1-7, wherein: and (3) recycling the filtrate obtained after the solid-liquid separation in the step (2) to the preparation process of the calcium-removing resin eluent.
9. The method according to any one of claims 1-8, wherein: the calcium-removing resin eluent in the step (1) is prepared by adopting the following method:
a. crushing the fly ash to be less than 100 meshes, carrying out wet magnetic separation to remove iron so as to reduce the content of iron oxide in the fly ash to be less than 1.0 wt%, then adding a hydrochloric acid solution into the fly ash for reaction and carrying out solid-liquid separation so as to obtain a hydrochloric acid leaching solution with the pH value of 1-3;
b. introducing the hydrochloric acid immersion liquid into an anion resin column for iron adsorption to obtain iron-removed hydrochloric acid immersion liquid;
c. introducing the hydrochloric acid leaching solution subjected to iron removal into a chelating resin column for calcium adsorption, and eluting with water or hydrochloric acid as an eluent after adsorption saturation to obtain a calcium-removal resin eluent;
preferably, the concentration of the hydrochloric acid in the step a is selected from 20-37 wt%, and the molar ratio of HCl in the hydrochloric acid to alumina in the fly ash is 4:1-9: 1;
preferably, the step of passing the hydrochloric acid leaching solution into an anion resin column in the step b comprises the following steps: passing the hydrochloric acid extract through an anion resin column from bottom to top at 60-90 deg.C, wherein the flow rate of the hydrochloric acid extract is 3-4 times of resin volume/hr;
preferably, the step of introducing the hydrochloric acid leaching solution into the chelating resin column in the step c comprises the following steps: and (3) passing the hydrochloric acid immersion liquid through a resin column from bottom to top at the temperature of 20-90 ℃, wherein the flow rate of the hydrochloric acid immersion liquid is 1-4 times of the volume of the resin per hour.
10. The method according to claim 1 or 2, characterized in that: the calcium-removing resin eluent comprises 20-43g/L Ca2+7.5-16g/L of Al3+1.6-8.5g/L of Mg2+，90-180g/Cl of L-(ii) a The pH value of the calcium-removing resin eluent is 1-3;
preferably, the calcium-removing resin eluent comprises 28-38g/L of Ca2+10-14g/L of Al3+4.5-8.1g/L of Mg2 +120-160g/L Cl-(ii) a The pH value of the calcium-removing resin eluent is 1.5-2.5.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010896680.5A CN112030222A (en) | 2020-08-31 | 2020-08-31 | Method for preparing calcium sulfate whisker by using calcium-removing resin eluent |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010896680.5A CN112030222A (en) | 2020-08-31 | 2020-08-31 | Method for preparing calcium sulfate whisker by using calcium-removing resin eluent |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112030222A true CN112030222A (en) | 2020-12-04 |
Family
ID=73586409
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010896680.5A Pending CN112030222A (en) | 2020-08-31 | 2020-08-31 | Method for preparing calcium sulfate whisker by using calcium-removing resin eluent |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112030222A (en) |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101550585A (en) * | 2009-04-16 | 2009-10-07 | 北京矿冶研究总院 | Preparation method of dehydrated calcium sulfate whisker |
| CN103755060A (en) * | 2013-12-27 | 2014-04-30 | 中国神华能源股份有限公司 | Dissolving-out slurry separation washing method used in coal ash acid-process aluminium oxide production process |
| US20150158997A1 (en) * | 2013-12-06 | 2015-06-11 | Georgia-Pacific Gypsum Llc | Gypsum composite modifiers |
| CN109650425A (en) * | 2018-12-13 | 2019-04-19 | 中国神华能源股份有限公司 | A method of recycling aluminium chloride from resin deliming eluent |
| CN110205671A (en) * | 2019-07-04 | 2019-09-06 | 江苏一夫科技股份有限公司 | It is a kind of to prepare Dihydrate gypsum whiskers, the method for hemihydrate calcium sulfate crystal whisker and product as made from it |
| CN111118606A (en) * | 2019-12-31 | 2020-05-08 | 浙江环耀环境建设有限公司 | Method for preparing calcium sulfate whiskers by using bone gelatin wastewater |
-
2020
- 2020-08-31 CN CN202010896680.5A patent/CN112030222A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101550585A (en) * | 2009-04-16 | 2009-10-07 | 北京矿冶研究总院 | Preparation method of dehydrated calcium sulfate whisker |
| US20150158997A1 (en) * | 2013-12-06 | 2015-06-11 | Georgia-Pacific Gypsum Llc | Gypsum composite modifiers |
| CN103755060A (en) * | 2013-12-27 | 2014-04-30 | 中国神华能源股份有限公司 | Dissolving-out slurry separation washing method used in coal ash acid-process aluminium oxide production process |
| CN109650425A (en) * | 2018-12-13 | 2019-04-19 | 中国神华能源股份有限公司 | A method of recycling aluminium chloride from resin deliming eluent |
| CN110205671A (en) * | 2019-07-04 | 2019-09-06 | 江苏一夫科技股份有限公司 | It is a kind of to prepare Dihydrate gypsum whiskers, the method for hemihydrate calcium sulfate crystal whisker and product as made from it |
| CN111118606A (en) * | 2019-12-31 | 2020-05-08 | 浙江环耀环境建设有限公司 | Method for preparing calcium sulfate whiskers by using bone gelatin wastewater |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| WO2015161660A1 (en) | Method for preparing low-silicon vanadium pentoxide from solution containing vanadium, chromium and silicon | |
| CN112142081B (en) | Method for preparing battery-grade lithium carbonate by using lepidolite | |
| CN104058378B (en) | The method of monoammonium phosphate and magnesium ammonium phosphate is produced with the acid of wet method concentrated phosphoric acid slag | |
| CN108975364B (en) | Method for removing alkali and recovering sodium by Bayer process red mud acid treatment | |
| CN110015855B (en) | Treatment method of lithium slag | |
| CN107758714B (en) | Method for synergistic extraction of aluminum, silicon, lithium and gallium in fly ash by combination method | |
| US5102512A (en) | Process for extracting and purifying gallium from bayer liquors | |
| CN110004294B (en) | Method for treating scheelite alkali decomposition slag | |
| CN110699756B (en) | Method for preparing alpha-type gypsum whisker by using ammonia-soda waste liquid | |
| WO2018192441A1 (en) | Method for use in producing battery-grade vanadium oxide | |
| CN109052430B (en) | Method for removing alkali by red mud acid treatment | |
| CN113292088B (en) | Method for producing low-magnesium and low-calcium alumina from crystalline aluminum chloride | |
| CN102701263B (en) | Method for preparing copper sulfate in mode that stanniferous copper slag is leached in selective mode and free of evaporation | |
| CN104046805A (en) | Method for recovering rare-earth ions from weathered crust illuviation-type rare-earth ore leaching solution | |
| US4024087A (en) | Method of preparing coagulant for purification of water from mechanical admixtures | |
| CN114572949A (en) | Production process of lithium dihydrogen phosphate | |
| CN110550646A (en) | preparation method of cesium sulfate and rubidium sulfate | |
| CN108862517B (en) | Process for co-producing heavy metal treatment coagulant by using phosphogypsum and red mud to prepare acid | |
| CN1454843A (en) | Magnesium sulfate hypotype salt lake brine magnesium lithium separation method | |
| US4366129A (en) | Process for producing alumina and ferric oxide from aluminium carriers with high iron and silicon content | |
| CN112030222A (en) | Method for preparing calcium sulfate whisker by using calcium-removing resin eluent | |
| CN114369729B (en) | Process for removing potassium from leaching solution by utilizing lithium slag | |
| CN112142073A (en) | Method for resource utilization of chromium-containing sodium bisulfate | |
| CN110004292B (en) | Process for purifying waste manganese sulfate solution to reduce content of calcium and magnesium | |
| CN109336151B (en) | Method for preparing aluminum chloride by using fly ash |
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 | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20201204 |
|
| RJ01 | Rejection of invention patent application after publication |