CN115093133A - High-activity calcium hydroxide suspension and efficient preparation method thereof - Google Patents
High-activity calcium hydroxide suspension and efficient preparation method thereof Download PDFInfo
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- CN115093133A CN115093133A CN202210709179.2A CN202210709179A CN115093133A CN 115093133 A CN115093133 A CN 115093133A CN 202210709179 A CN202210709179 A CN 202210709179A CN 115093133 A CN115093133 A CN 115093133A
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- 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
- C04B2/00—Lime, magnesia or dolomite
- C04B2/02—Lime
- C04B2/04—Slaking
- C04B2/06—Slaking with addition of substances, e.g. hydrophobic agents ; Slaking in the presence of other compounds
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Abstract
The invention discloses a high-activity calcium hydroxide suspension and an efficient preparation method thereof, wherein under the state that a stirrer is continuously stirred or a rotary drum is continuously rotated, digestion water and reactant quicklime are simultaneously and continuously added into a reactor in proportion, and the reaction temperature and the retention time are controlled, so that the time of the digestion reaction temperature of more than 60 ℃ is not more than 60 minutes and not less than 20 minutes; and collecting the reacted mixed liquor, and carrying out hydrocyclone separation and/or screening on the obtained mixed liquor to remove large-particle impurities in the mixed liquor so as to obtain a target calcium hydroxide suspension finished product. Compared with the traditional intermittent process of firstly adding water and then adding ash, the process has the advantages of short time, high efficiency, relatively gentle temperature change of a reaction system along with time, more balanced integral reaction speed, reduction of primary particle size and agglomeration of calcium hydroxide, and contribution to obtaining calcium hydroxide suspension with lower viscosity on the basis of keeping certain reaction activity.
Description
Technical Field
The invention belongs to the technical field of calcium hydroxide production, and relates to a high-activity calcium hydroxide suspension and an efficient preparation method thereof.
Background
The calcium hydroxide is widely applied in the water treatment fields of neutralization of acidic wastewater, removal of heavy metal ions, phosphate ions, sulfate ions, fluoride ions and the like. In water treatment practice, calcium hydroxide is generally used as a suspension with water or after a calcium hydroxide suspension is obtained by wet digestion of calcium oxide.
The calcium hydroxide has the advantages of good safety and lower price than inorganic alkaline treatment agents such as sodium hydroxide, sodium carbonate and the like, but the defects mainly comprise two aspects: firstly, calcium hydroxide is slightly soluble in water, and compared with water-soluble alkali such as sodium hydroxide and the like, when a chemical reaction occurs, the calcium hydroxide is firstly dissolved in water, and then calcium ions or hydroxyl ions react with harmful substances in wastewater, so that the treatment speed of the calcium hydroxide is slower than that of the water-soluble alkali such as sodium hydroxide and the like when the calcium hydroxide is used for treating the wastewater, and the efficiency of water treatment is influenced; secondly, the solid content of the common calcium hydroxide suspension is 5-10% (while the concentration of the sodium hydroxide solution commonly used for water treatment is more than 30%), and the viscosity of the suspension is too high due to the high concentration, so that the suspension is difficult to convey and measure, and the production load and the production cost in the pulp preparation link are obviously increased. In addition to the two main defects, calcium hydroxide has the problems of incomplete reaction, excessive addition, high impurity content, increase of water treatment sludge amount and the like. Therefore, from the application point of view, calcium hydroxide suspension with high reactivity, high solid content, low viscosity and low impurity content is ideal for the water treatment industry.
It has been found that the dissolution rate of calcium hydroxide in water is related to the particle size, the smaller the particle size, the faster the dissolution rate, and correspondingly the faster the chemical reaction rate, the better the reactivity of calcium hydroxide. At the same time, however, the smaller the particle size, the greater the viscosity of the suspension, which limits the increase in the calcium hydroxide content of the suspension. Therefore, it is technically difficult to obtain a calcium hydroxide suspension having high reactivity, high content and low viscosity at the same time.
To solve the above problems, a great deal of research has been conducted, mainly including:
(1) the viscosity of the suspension is reduced by using an additive which can form precipitates or slightly soluble substances with calcium ions, for example, when calcium oxide is subjected to a digestion reaction with water, substances such as gypsum and the like are added into the water to reduce the viscosity of lime milk. However, this method causes a decrease in the reactivity of calcium hydroxide.
(2) The viscosity is reduced by adding an organic polymer dispersant during the preparation of the calcium hydroxide suspension or during the wet digestion of calcium oxide, for example, the viscosity of the calcium hydroxide suspension is reduced by adding a polyacrylate dispersant in patent WO2018/048633A 1. Although the addition of the dispersant can reduce the viscosity of the suspension, the primary particle size of the calcium hydroxide cannot be reduced, i.e., the reactivity of the calcium hydroxide is not improved.
(3) The method of wet milling (or milling + dispersing agent) is used to reduce the particle size of the calcium hydroxide and thereby increase the reactivity of the calcium hydroxide, as disclosed in US 2019002301. The method increases the preparation steps of the suspension, is more complicated, and increases the addition proportion of corresponding additives although the particle size is reduced, thereby bringing obvious influence on the production cost.
(4) High activity, low viscosity suspensions were prepared by varying the digestion process. For example, in patents CN106470960 and US2019092684, suspensions of calcium hydroxide are prepared by stepwise addition of water to lime, the water containing a dispersant or an inorganic salt. This approach is highly demanding for digestion equipment because at low water-to-ash ratios the lime slake product is pasty and has a very high viscosity that ordinary equipment cannot meet.
In addition to the above studies, there are problems in the industry with the preparation of environmentally friendly calcium hydroxide suspensions. In the industrial practice of water treatment, calcium hydroxide suspension is generally produced by a batch method, i.e. after water is added into a digestion tank, lime is added into the tank for digestion reaction, and after the digestion reaction is finished, digestion slurry is pumped away by a pump for subsequent water treatment and other steps. The intermittent process of adding water and then adding ash has the advantages of simplicity and easy operation, but has the following problems:
the operation time is longer. The water adding and the ash adding are carried out in series (sequentially), the operation time comprises the water adding time and the ash adding time, the total time is longer, and the efficiency is lower.
② the scale of a single batch is difficult to be made large. If the yield of each batch is to be improved, the ash adding amount of each batch is improved, and if the ash adding speed is not changed, the ash adding time is prolonged, so that the total operation time is prolonged, and the efficiency is reduced; and if the ash adding speed is increased, the problem that water and ash are difficult to be quickly and uniformly mixed exists, and the fluctuation of the product quality is easily caused. Therefore, it is difficult to increase the production scale of a single batch for a batch-wise process of adding water first and then ash.
And the digestion reaction speed of the calcium oxide is continuously accelerated along with the rise of the temperature, different particle sizes can be caused by different reaction speeds, and then slurry with different reaction activities and viscosities is formed. The traditional intermittent process of adding water first and then adding ash has the advantages that the temperature of a reaction system is continuously accelerated along with the time change, the reaction speed is also continuously accelerated along with the temperature rise, the primary particle size of calcium hydroxide is not uniform, and the calcium hydroxide is easy to agglomerate.
In summary, the methods for preparing calcium hydroxide suspension in the prior art have many disadvantages, such as difficulty in preparing calcium hydroxide suspension with high calcium hydroxide content, low viscosity and high reactivity, long production time and low efficiency.
Disclosure of Invention
In order to fill the blank of the prior art, the invention provides a high-activity calcium hydroxide suspension and an efficient preparation method thereof, which overcome the defects of the prior art, and simultaneously add digestion water and reactant quicklime into a reactor, thereby reducing the production time and improving the production efficiency.
The technical scheme of the invention is as follows:
a high-efficiency preparation method of a high-activity calcium hydroxide suspension comprises the following steps:
s1: preparation of reactant quicklime: crushing and sieving quicklime to obtain quicklime with particle size smaller than 8mm, namely reactant quicklime, weighing for later use, wherein the quicklime is high-activity quicklime with activity higher than 360;
s2: preparation of water for digestion: adding water into a container with a stirrer, adding an active promoter and/or a stabilizer into the water, stirring until the water is completely dissolved to prepare water for digestion, wherein the mass of the water for digestion is 2-4 times that of reactant quicklime, the total mass of the active promoter and/or the stabilizer is 0.5-4% of that of the reactant quicklime, the water temperature of the water for digestion is 15-40 ℃, the active promoter is a substance which can make the water alkaline after being dissolved in the water and is mixed with the calcium hydroxide to avoid generating precipitates, and the stabilizer is one or a mixture of micromolecular dispersant, sugar alcohol and saccharide;
s3: digestion reaction: under the state of continuous stirring, simultaneously and continuously adding the digestion water and the reactant quicklime into the reactor in proportion, finishing feeding within 15min, and after the feeding is finished, controlling the reaction temperature and the retention time to ensure that the time of the digestion reaction temperature above 60 ℃ is not more than 60 minutes and not less than 20 minutes, and finishing the reaction;
s4: and collecting the reacted mixed liquor, and performing hydrocyclone separation and/or screening on the obtained mixed liquor to remove large-particle impurities in the mixed liquor to obtain a finished product of the target calcium hydroxide suspension.
Further, in the S1, the particle size of the screened standby quicklime is less than 5 mm.
Further, in the S1, the activity degree of the high-activity quicklime is not lower than 380.
Further, the feeding time in the S3 is controlled within 10 min.
Further, the activity promoter is one or a mixture of more of sodium hydroxide, potassium hydroxide, sodium acetate, sodium formate, monoethanolamine, diethanolamine and triethanolamine.
Further, the stabilizer is one or a mixture of potassium pyrophosphate, sodium hexametaphosphate, xylitol, sorbitol, erythritol, sucrose, glucose and fructose.
Further, the ratio of the total mass of the active accelerant and/or the stabilizer to the mass of the ready quicklime is 10: 1000-30: 1000.
a high-activity calcium hydroxide suspension is prepared by any one of the preparation methods, wherein the calcium hydroxide suspension has the mass content of 25-45%, the particle size distribution is that D50 is more than or equal to 3 mu m and less than or equal to 6 mu m, D97 is more than or equal to 23 mu m, Di00 is more than or equal to 45 mu m, the viscosity is less than or equal to 350 centipoises (namely cP, 1cP is equal to 1mPa.s) at 25 ℃, and the reaction activity t90 is more than or equal to 4.5 seconds.
The quicklime mentioned in step S1 is tested according to the method specified in YB/T105-2005 metallurgical lime physical inspection method, the activity degree is not lower than 360, preferably not lower than 380, and the use of the quicklime with lower activity can cause the digestion reaction speed to be slow and the reaction activity of the calcium hydroxide to be reduced. The method has the advantages that the quicklime is crushed and then used, so that the digestion reaction process is more uniform and stable, the phenomena of bumping, local overheating and the like caused by porous massive lime are reduced, and the stability of product quality is facilitated. The lime granules after crushing and sieving are not suitable to be larger than 8m, otherwise the phenomena of bumping and the like are easily caused; the size of the crushed and sieved quicklime particles is preferably less than 5mm, and experiments show that the size has more remarkable effect on eliminating phenomena such as bumping and the like.
In step S2, a temperature of the water for digestion lower than 15 ℃ leads to a decrease in reactivity of the resulting calcium hydroxide suspension, while a temperature higher than 40 ℃ leads to a significant increase in viscosity of the calcium hydroxide suspension. The mentioned active promoter is a substance which can make water alkaline after being dissolved in water, but does not include a substance which can react with calcium hydroxide to generate precipitate, and sodium hydroxide, potassium hydroxide, sodium acetate, sodium formate, monoethanolamine, diethanolamine, triethanolamine and the like are preferred. The mentioned stabilizer has double functions of improving the reaction activity of calcium hydroxide and reducing the agglomeration of calcium hydroxide particles, can be used alone or together with an activity promoter, and preferred stabilizers include small molecular dispersing agents such as potassium pyrophosphate, sodium hexametaphosphate, sugar alcohols such as xylitol, sorbitol, erythritol and sugar substances such as sucrose, glucose, fructose and the like. The total mass of the active accelerant and/or stabilizer added is 0.5-4%, preferably 1-3% of the mass of the active quicklime. The mass ratio of water and ash in the digestion reaction is 2: 1-4: 1, the viscosity is too high when the water and ash ratio is too low, and the content of calcium hydroxide in the suspension is lower when the water and ash ratio is higher than 4: 1, so the economy is not good. The quicklime and the water for digestion are respectively metered into the digestion reactor according to a set proportion, the adding speed is determined according to the volume of the reactor, the mixing capability of a stirring paddle and the capability of feeding equipment (such as a feeding screw rod, a pump and the like), the material adding time is generally not more than 15 minutes, preferably not more than 10 minutes from the viewpoint of production efficiency, and the mass ratio of the added water to the quicklime at any time in the feeding stage is ensured to meet the set value requirement.
In step S3, when calcium oxide and water are subjected to a digestion reaction to generate calcium hydroxide, heat is released to increase the temperature of the reaction system, and for the preparation of calcium hydroxide suspension, the temperature increase is favorable for the digestion reaction to be more complete, but the long-term high temperature can cause the reaction activity of calcium hydroxide to be reduced, so that the time of the digestion reaction temperature above 60 ℃ is not more than 60 minutes and not less than 20 minutes from the completion of the addition of the materials.
In step S4, the suspension obtained from the digestion reaction discharge is subjected to a hydrocyclone and/or a vibrating screen to remove large particles, which can remove unreacted impurities carried in the lime raw material, such as silica, alumina, and unburnt limestone, thereby increasing the content of calcium hydroxide in the suspension and reducing the amount of sludge generated during sewage treatment.
In conclusion, the beneficial effects of the invention are as follows:
(1) the process of adding water and quicklime simultaneously is adopted in the feeding stage, so that compared with the process of adding water first and then adding lime, the process can effectively reduce the feeding time and improve the production efficiency; on the other hand, the water and the lime are added simultaneously according to the proportion, so that the water and the lime are easier to be mixed uniformly, the uniformity of the reaction and the stability of the product quality are improved, the bottleneck that the scale of single-batch secondary production is difficult to be enlarged in the traditional process of adding water first and adding lime later is broken through, and the mass production is easier to realize.
(2) The digestion reaction speed of the calcium oxide is continuously accelerated along with the temperature rise, and different particle sizes can be caused by different reaction speeds, so that slurry with different reaction activities and viscosities is formed. Compared with the traditional intermittent process of adding water and lime at first and then adding lime, the process of the invention has the advantages that the temperature of the reaction system changes relatively gently along with time, the overall reaction speed is more balanced, the primary particle size and agglomeration of calcium hydroxide are reduced, and the process is favorable for obtaining a calcium hydroxide suspension with lower viscosity on the basis of keeping certain reaction activity.
(3) According to the invention, through the accurate control of raw materials, processes and auxiliaries, the calcium hydroxide suspension with high reaction activity, high calcium hydroxide content and low viscosity can be obtained, most impurities in the suspension can be removed through a hydrocyclone separation or sieving method, and the problems of low reaction speed, low production efficiency, high addition amount, more sludge and the like existing in the existing calcium hydroxide application in water treatment are improved.
(4) The invention does not use expensive polymer dispersant, the used additives are common small molecular chemical reagents, and the optimal effect is realized by the combination of different reagents; meanwhile, the invention does not need special equipment (such as a high-torque digester and the like), has simple operation and short reaction flow, and is favorable for reducing the manufacturing cost of the suspension.
Detailed Description
The following describes in detail embodiments of the present invention.
Example 1
S1, preparation of reactant quicklime: crushing high-activity quicklime with the activity degree of 400 by using a crusher, sieving to select powder with the particle size less than 8mm, adding the powder into a charging barrel, wherein the charging barrel is provided with a discharging device for controlling the discharging speed, and the reactant quicklime powder added into the charging barrel is 12.5 kg;
s2: preparation of water for digestion: adding 49.9kg of water into a tank (container) with a stirrer, controlling the water temperature at 40 ℃, adding 50g of sodium hydroxide and 50g of potassium pyrophosphate into the water, and controlling a flow control valve of a discharging speed in the tank;
s3: 0.08m with condensate return device 3 In the stirring type reactor, the mass ratio of the digestion water and the reactant quicklime added into the reactor per minute is controlled to be 4: 1 under the stirring state, and the addition is finished within 10 minutes, namely 5kg of the digestion water and 1.25kg of the reactant quicklime are added per minute. After mixing the quicklime and the water, quickly heating a reaction system to above 60 ℃, timing for 60 minutes from the temperature reaching 60 ℃, stopping stirring, and finishing the digestion reaction;
s4: and collecting the reacted mixed solution, and sieving the obtained mixed solution by a 200-mesh sieve to remove large-particle impurities in the mixed solution to obtain a finished product of the target calcium hydroxide suspension.
The content of the calcium hydroxide in the obtained calcium hydroxide suspension is tested according to the method specified in GB/T27815-2011 Industrial milky calcium hydroxide; the viscosity of the suspension is tested by using an NDJ-9S rotational viscometer, the temperature of the suspension is stabilized at 25 ℃, and the suspension is tested by using a No. 2 or No. 3 rotor at the rotating speed of 60 revolutions per minute; the particle size distribution of the solid particles in the suspension was tested using a laser particle sizer; the reactivity of calcium hydroxide in the suspension is determined by conductivity method, i.e. according to the content of calcium hydroxide in the suspension, 0.1g of the suspension containing calcium hydroxide is weighed, the suspension is rapidly poured into 700g of deionized water (water temperature is 25 ℃), the change of the conductivity of the deionized water along with time is recorded, and the time consumed from pouring the calcium hydroxide suspension until the conductivity reaches 90% of the maximum value is calculated and recorded as t90, and the smaller t90, the faster the dissolution speed of calcium hydroxide is, and the higher the reactivity is.
Through determination, the calcium hydroxide suspension prepared in this example has the following indexes: the calcium hydroxide has a mass content of 25%, t90 ═ 4.5 seconds, viscosity of 140cP, D50 ═ 5.7 μm, D97 ═ 20.5 μm, and D100 ═ 40 μm.
Example 2
With reference to example 1, 0.08m with condensate return 3 In a stirring type reactor, under the stirring state, slaking water and reactant quicklime are respectively added into the reactor at the speed of 8 kg/min and 4 kg/min, 40kg of water and 20kg of quicklime are added into the reactor for 5min, wherein the activity of the quicklime is 360, the granularity is less than 8mm, the water temperature is 15 ℃, and 90g of sodium acetate and 400g of glucose are dissolved in the slaking water. After the quicklime and the water are mixed, the reaction system is quickly heated, after the temperature exceeds 60 ℃, the stirring is continued for 20 minutes, then the stirring is stopped, the mixed liquid after the reaction is discharged from the reaction kettle and passes through a 200-mesh sieve, and the calcium hydroxide suspension with the calcium hydroxide content of 45 percent, the t90 of 3.5 seconds, the viscosity of 350cP, the D50 of 3 micrometers, the D97 of 16.2 micrometers and the D100 of 34.5 micrometers is obtained through detection.
Example 3
With reference to example 1, 0.08m with condensate return 3 In the stirring type reactor, under the stirring state, the reaction is respectively carried outWater for digestion and quicklime as a reactant were fed to the reactor at rates of 12 kg/min and 4 kg/min, 48kg of water and 16kg of quicklime were fed to the reactor at 4 min, wherein the quicklime activity was 380, the particle size was < 5mm, the water temperature was 20 ℃, and 320g of sorbitol and 160g of sodium hexametaphosphate were dissolved in the water for digestion. After quicklime and water are mixed, the reaction system is rapidly heated, after the temperature exceeds 60 ℃, stirring is continuously carried out for 40 minutes, then stirring is stopped, the mixed liquid after reaction is discharged from the reaction kettle and passes through a 200-mesh sieve, and calcium hydroxide suspension with the calcium hydroxide content of 35 percent, the t 90-4 seconds, the viscosity of 242cP, the D50-5.2 micrometers, the D97-18.8 micrometers and the D100-42.5 micrometers is obtained through detection.
Example 4
Reference example 1, 0.08m with condensate return 3 In a stirring type reactor, under the stirring state, digestion water and reactant quicklime are respectively added into the reactor at the speed of 3.3 kg/min and 0.83 kg/min, 50kg of water and 12.5kg of quicklime are added into the reactor for 15min, wherein the activity of the quicklime is 390, the granularity is less than 5mm, the water temperature is 30 ℃, and 125g of triethanolamine, 125g of xylitol and 250g of sucrose are dissolved in the digestion water. After quicklime and water are mixed, the reaction system is rapidly heated, after the temperature exceeds 60 ℃, stirring is continued for 30 minutes, then stirring is stopped, the mixed solution after reaction is discharged from the reaction kettle and passes through a 200-mesh sieve, and a calcium hydroxide suspension with the calcium hydroxide content of 25%, t90 of 4.3 seconds, the viscosity of 158cP, D50 of 6 micrometers, D97 of 23 micrometers and D100 of 45 micrometers is obtained through detection.
Comparative example
The calcium hydroxide suspension is produced by adopting the traditional intermittent process of firstly adding water and then adding ash, the used raw materials, equipment, the auxiliary agent proportion and the like are the same as those in the example 1, and the specific description is as follows:
0.08m with condensate return device 3 In a stirred reactor, 50kg of digestion water at 40 ℃ was first added to the reactor, 50g of sodium hydroxide and 50g of potassium pyrophosphate being dissolved in the digestion water. 12.5kg of quicklime (particle size < 8mm, added over 10 minutes) having an activity of 400 were added to the water with stirring. After the quicklime is added, the reaction system is quickly heated until the quicklime is addedAfter the temperature exceeded 60 ℃, stirring was continued for 60 minutes, then stirring was stopped, and the mixed solution after the reaction was discharged from the reaction kettle and passed through a 200-mesh sieve, and detection was carried out to obtain a calcium hydroxide suspension having a calcium hydroxide content of 25%, a t90 of 4.0 seconds, a viscosity of 182cP, a D50 of 5.2 μm, a D97 of 17.8 μm, and a D100 of 40 μm.
The comparison shows that the process of simultaneously adding water and quicklime in proportion is used, compared with the traditional intermittent process of adding water firstly and then adding lime, the activity of the calcium hydroxide suspension obtained by the reaction is slightly fluctuated, but the viscosity is obviously reduced, and the method is suitable for the application field with higher requirement on the viscosity control of the suspension.
In conclusion, the process can produce the calcium hydroxide suspension with high reactivity, high calcium hydroxide content and low viscosity, and the calcium hydroxide suspension has the performance indexes that the mass content of the calcium hydroxide is about 25-45%, the particle size distribution is that D50 is more than or equal to 3 mu m and less than or equal to 6 mu m, D97 is more than or equal to 23 mu m, D100 is less than or equal to 45 mu m, the viscosity is less than or equal to 350 centipoises (centipoise namely cP, 1cP is 1mPa.s), and the reactivity t90 is less than or equal to 4.5 seconds. The process design is exquisite, the flow is short, expensive equipment and additives are not needed, the cost is low, and the applicability is high; compared with the traditional intermittent process of adding water first and then adding ash, the process has the advantages of short time, high efficiency, relatively gentle temperature change of a reaction system along with time, and more balanced overall reaction speed, so that the size and agglomeration of primary particles of calcium hydroxide are reduced, and the process is favorable for obtaining a calcium hydroxide suspension with lower viscosity on the basis of keeping certain reaction activity.
The foregoing shows and describes the general principles, essential features, and advantages of the invention. The present invention is not limited to the above-described embodiments, which are described in the specification and illustrated only for illustrating the principle of the present invention, but various changes and modifications may be made within the scope of the present invention as claimed without departing from the spirit and scope of the present invention. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (8)
1. A high-efficiency preparation method of high-activity calcium hydroxide suspension is characterized by comprising the following steps: the method comprises the following steps:
s1: preparation of reactant quicklime: crushing and sieving quicklime to obtain quicklime with particle size smaller than 8mm, namely reactant quicklime, weighing for later use, wherein the quicklime is high-activity quicklime with activity higher than 360;
s2: preparation of water for digestion: adding water into a container with a stirrer, adding an active promoter and/or a stabilizer into the water, and stirring until the active promoter and/or the stabilizer are completely dissolved to prepare slaking water, wherein the mass of the slaking water is 2-4 times of the mass of the reactant quicklime, the total mass of the active promoter and/or the stabilizer is 0.5-4% of the mass of the reactant quicklime, the water temperature of the slaking water is 15-40 ℃, the active promoter is a substance which can make the water alkaline after being dissolved in the water and is mixed with the calcium hydroxide to avoid generating precipitates, and the stabilizer is one or a mixture of a micromolecule dispersant, sugar alcohol and saccharide;
s3: digestion reaction: under the state of continuous stirring, simultaneously and continuously adding the digestion water and the reactant quicklime into the reactor in proportion, finishing feeding within 15min, and after the feeding is finished, controlling the reaction temperature and the retention time to ensure that the time of the digestion reaction temperature above 60 ℃ is not more than 60 minutes and not less than 20 minutes, and finishing the reaction;
s4: and collecting the reacted mixed liquor, and carrying out hydrocyclone separation and/or screening on the obtained mixed liquor to remove large-particle impurities in the mixed liquor so as to obtain a target calcium hydroxide suspension finished product.
2. The method for efficiently preparing a suspension of high-activity calcium hydroxide according to claim 1, wherein: in the S1, the particle size of the screened standby quicklime particles is less than 5 mm.
3. The method for efficiently preparing a suspension of high-activity calcium hydroxide according to claim 1, wherein: in S1, the activity degree of the high-activity quicklime is not lower than 380.
4. The method for efficiently preparing a suspension of high-activity calcium hydroxide according to claim 1, wherein: and the feeding time in the S3 is controlled within 10 min.
5. The method for efficiently preparing a suspension of high-activity calcium hydroxide according to claim 1, wherein: the activity promoter is one or a mixture of more of sodium hydroxide, potassium hydroxide, sodium acetate, sodium formate, monoethanolamine, diethanolamine and triethanolamine.
6. The method for efficiently preparing a suspension of high-activity calcium hydroxide according to claim 1, wherein: the stabilizer is one or more of potassium pyrophosphate, sodium hexametaphosphate, xylitol, sorbitol, erythritol, sucrose, glucose and fructose.
7. The method for efficiently preparing a suspension of high-activity calcium hydroxide according to claim 1, wherein: the ratio of the total mass of the active accelerant and/or the stabilizer to the mass of the ready-for-use quicklime is 1% to 3%.
8. A high-activity calcium hydroxide suspension is characterized in that: the calcium hydroxide suspension prepared by any one of the preparation methods has the calcium hydroxide content of about 25-45% by mass, the particle size distribution of D50 which is less than or equal to 3 mu m and less than or equal to 6 mu m, D97 which is less than or equal to 23 mu m, D100 which is less than or equal to 45 mu m, the viscosity which is less than or equal to 350 centipoises (namely cP, 1cP which is 1mPa.s) at 25 ℃, and the reaction activity t90 which is less than or equal to 4.5 seconds.
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