JP2963626B2 - Low adhesion slaked lime and method for modifying it - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a modified low-adhesion slaked lime and a method for reforming slaked lime, and more particularly to slaked lime produced by a conventional method, particularly when transporting, storing and pumping tanks. The present invention relates to a method for reforming low-adhesion slaked lime and slaked lime by industrially modifying powdered slaked lime which is difficult to adhere or solidify in a pipe or inside.

[0002]

2. Description of the Related Art Calcium oxide (hereinafter referred to as quicklime)
As a method of industrially producing slaked lime using as a raw material,
There is known a method in which quick lime is charged into a digester equipped with a water hydration device, hydrated and digested, and then aged in a ripening machine to produce slaked lime. The slaked lime produced by this production method is temporarily stored in a storage tank and then bagged via a pipe, or transferred as it is to a tank transporter to be used at a place of use. If slaked lime adheres or stays in the storage tank or transfer pipe when it is taken out or transferred from the storage tank after manufacture, the physical properties of the storage tank or transfer pipe, such as applying vibration or impact, or pecking with a stick, etc. Slaked lime adhering or staying in storage tanks and transfer pipes is removed using a conventional method, and no solution has been taken at present except to prevent or reduce it by such a method. Furthermore, there is no conventional treatment or operation to reprocess the already produced slaked lime itself to improve the product to be hardly adhered.

[0003]

When slaked lime is manufactured or removed from a storage tank or transferred as described above, if the storage tank or the transfer pipe adheres or stays, vibration or lime may be applied to the storage tank or the transfer pipe. The method of removing slaked lime adhered or retained on storage tanks and transfer pipes by using physical methods such as hitting and pecking with a stick etc. requires time-consuming and inefficient cleaning of pipes and tanks. Not only that, slaked lime as produced by conventional methods has the property of easily adhering to the inner walls of storage tanks and transfer pipes,
It solidifies, and further slaked lime adheres to it, eventually causing shelving and blockage in the tank, and localization of the solidified material to form clumps, resulting in reduced function and blockage of valves and pipes. It was a problem because it could be an obstacle to occur.

The inventor of the present invention has conducted various studies to solve the above-mentioned problems. As a result, the additive was added to the conventional slaked lime, or after the additive was added, a certain treatment was performed to obtain the adhering material. Found that it can reduce the
Here, the present invention has been accomplished. Therefore, the problem to be solved by the present invention is to provide a method for reforming slaked lime which can industrially advantageously produce slaked lime which hardly adheres or hardens in pipes and tanks during storage and transfer. .

[0005]

Means for solving the above problems are achieved by the following inventions. (1) hydrated lime, powdered quick lime and, glycols, Ri Do at least one additive selected from glycol ethers or ethanolamines, wherein the slaked lime and powdered
A modified low-adhesion slaked lime, wherein the weight ratio of quicklime is 98: 2 to 70:30. (2) The modified low-adhesive slaked lime according to (1), wherein the glycol is at least one selected from ethylene glycol, diethylene glycol, triethylene glycol and tetraethylene glycol. (3) glycol ethers are ethylene glycol dimethyl ether, ethylene glycol diethyl ether,
At least one selected from diethylene glycol monomethyl ether, triethylene glycol monomethyl ether or triethylene glycol monoethyl ether;
2. The modified low-adhesive slaked lime according to the above item 1, wherein (4) The modified low-adhesion slaked lime according to (1), wherein the ethanolamine is at least one selected from monoethanolamine, diethanolamine and triethanolamine. (5) The first method, wherein the addition amount of glycols, glycol ethers or ethanolamines diethylene glycol is 0.5 to 5.0 parts by weight based on the total of slaked lime and powdered lime . Item 5. The modified low-adhesive slaked lime according to any one of Items 4 to 4 . (6) The total amount of diethylene glycol and triethylene glycol added simultaneously is 0.5 parts by weight to 5.0 parts by weight based on the total of slaked lime and powdered lime. 3. The modified low-adhesive slaked lime according to item 2. (7) The weight ratio of slaked lime and powdered lime is 98: 2 to 7
At least one additive selected from glycols, glycol ethers or ethanolamines is added to the mixture at 0:30, mixed, and then the resulting mixture is heated. Quality way. (8) The seventh aspect, wherein the amount of the diethylene glycol added to the glycols, glycol ethers, or ethanolamines is 0.5 to 5.0 parts by weight based on the total of slaked lime and powdered lime . The method for reforming slaked lime according to the above item . (9) The method for modifying slaked lime according to the above (7) or (8) , wherein the heating temperature is maintained at 30 ° C to 175 ° C. (10) The method for modifying slaked lime according to any one of the above (7) to (9) , wherein the heating time is 30 minutes to 100 hours.

Hereinafter, the present invention will be described in more detail. The present invention relates to slaked lime produced by a conventional method and powdered slaked lime and at least one additive selected from glycols, glycol ethers or ethanolamines. Weight of the slaked lime and powdered lime in the mixture to which the
After the mixture having a ratio of 98: 2 to 70:30 or after mixing, the obtained mixture is heated to obtain slaked lime having low adhesion, and the obtained mixture is at room temperature. For a long period of time or at a temperature higher than room temperature for a certain period of time. Here, the weight ratio of slaked lime and powdered lime is
More specifically , it is 98: 2 to 70:30 . More specifically , the addition amount of powdered lime is based on the sum of slaked lime and powdered lime.
2 to 30% by weight, preferably 5 to 1% by weight.
It is to be added in the range of 5% by weight . If the addition amount of powdered lime is less than 2% by weight, the generated water cannot be absorbed sufficiently, so that there is no effect in reducing the adhesive force. If it exceeds 30% by weight, the properties as slaked lime become insufficient and the quality of slaked lime becomes poor. It is not preferable because it lowers. The powdered lime is obtained by pulverizing this lump since ordinary quick lime is in a lump.

In the present invention, powdered lime and glycols such as diethylene glycol or triethylene glycol are mixed with slaked lime to form a chemical reaction between them, whereby slaked lime is modified and adhered to a container or a transfer pipe. Or it changes into slaked lime with low adhesion between slaked limes. In the present invention, when powdered lime and glycols are mixed with slaked lime, powdered lime and glycols may be mixed simultaneously with slaked lime, or powdered lime may be added to slaked lime, and then glycols may be added and the whole may be mixed. Further, powdered lime may be added after adding glycols to slaked lime, and further, a mixture of glycols and powdered lime may be added to slaked lime. Preferably, powdered lime and glycols are mixed simultaneously with slaked lime, or powdered lime is added to slaked lime, and then glycols are added and the whole is mixed.

In the present invention, the amount of glycols, glycol ethers or ethanolamines (hereinafter sometimes referred to as an additive when these are collectively referred to) is defined as the total amount of slaked lime and powdered lime. On the other hand,
0.5% by weight to 5.0% by weight, preferably 1 to 3%.
Good results are obtained by adding in the range of weight%. The additive amount of the additive to the total of slaked lime and powdered lime is 0.
When the content is less than 5% by weight, the effect of reducing the adhesive force is poor,
Further, even if the added amount exceeds 5.0% by weight, the effect does not increase, so that adding more than this is economically disadvantageous. Further, in the present invention, the mixture obtained as described above is heated at a temperature of from room temperature to 175 ° C, more preferably, the heating temperature is 30 ° C to 100 ° C, and the heating time is 30 minutes to 30 minutes. 100 hours. Preferably, it is 2 hours to 60 hours. When the heating temperature is lower than the room temperature, the reaction takes too much time and is inefficient for industrial production. On the other hand, if the heating temperature exceeds 175 ° C., the adhesive force increases and the initial purpose cannot be achieved. Further, if the heating time is less than 30 minutes, the chemical reaction does not sufficiently proceed. The heating time is 1
If the time is longer than 00 hours, it returns like the temperature and the adhesive force increases, which is not preferable. Therefore, in more detail, the relationship between the heating temperature and the heating time is preferably adjusted appropriately between them. For example, good results are obtained within a range of 3 days at 30 ° C. and within 7 hours at a temperature of 100 ° C. Can be This means that the progress of the chemical reaction is generally proportional to the product of the temperature and the time, so that the temperature and the heating time extend in this case. Therefore, if the gist of the present invention is satisfied,
The present invention is not limited to the example of the range of the heating temperature and the time shown here.

In the present invention, glycols, glycol ethers or ethanolamines may be used as a mixture of at least one kind thereof, and even glycols such as diethylene glycol and triethylene glycol may be used. Even if species or three or more species are used in combination, their effects do not hinder each other and can be used without any problem. Further, in the case of glycol ethers or ethanolamines, two or more individual compounds can be used as a mixture. The mixing ratio of these compounds is arbitrary. In the present invention, a reaction between slaked lime and glycols, for example, diethylene glycol and triethylene glycol are organic chemicals having polarities (electrical + and-centers are unevenly distributed in the molecule), and gradually volatilize at room temperature, It has a moderate boiling point that is not extremely high, and easily reacts with calcium. Here, it can be considered that the cause of the adhesion of the slaked lime powder is that one of the particles generates an electrostatic force. Diethylene glycol or triethylene glycol coexisting with slaked lime gradually evaporates at a temperature slightly lower than the boiling point and disperses sufficiently in slaked lime powder.As a result of chemical bonding with calcium in slaked lime, its polarity causes an electrostatic force due to its polarity. It is considered that the adhesion of slaked lime decreases due to neutralization.

As a result of the chemical reaction between calcium and diethylene glycol or triethylene glycol, water is produced, which is absorbed by the coexisting quick lime and becomes slaked lime by the chemical reaction, so that adhesion by water is prevented.
The generated water has a function of inhibiting the progress of a chemical reaction between slaked lime and the additive, but the reaction proceeds continuously because quicklime absorbs the water. Since not all of the calcium hydroxide generated in this way becomes the surface of the particles, the reaction is terminated when the unreacted glycols disappear or the unreacted calcium on the surface of the particles disappears. In the modification of slaked lime, if the heating temperature is too high or the heating time is too long, glycols and the like are evaporated and the effect is reduced.
Therefore, an appropriate amount of the additive such as glycol, the heating temperature and the holding time are important factors.

[0011]

In the present invention, quicklime has an action of absorbing water generated as a result of the reaction between slaked lime and glycols. By adding quicklime to slaked lime, glycols and the like are added therein, and the glycols and the like are heated,
It is easily dispersed among slaked lime particles and binds with calcium on the surface of slaked lime particles. As a result, water is generated, and this water is absorbed by quick lime and chemically reacted to form slaked lime. Glycols and the like also act on calcium on the surface of slaked lime particles generated from quicklime obtained by reacting with water as described above, and the particle surface is covered with the glycols and the like. However, glycols and the like hardly enter the inside of the slaked lime particles, and the reaction becomes slow and ends. In addition, it is considered that glycols and the like chemically bond with slaked lime and neutralize an electrostatic force by its polarity, so that the adhesion of slaked lime is reduced. In the present invention, heating the mixture of slaked lime, quicklime and additives has an effect of accelerating the chemical reaction.

[0012]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example 10% by weight of powdered lime was added to 90% by weight of slaked lime, and then glycols were added and mixed well, followed by heating for a predetermined time to produce slaked lime of the present invention. Here, the addition amounts of the powdered lime and the glycols, the heating temperature and the heating time were set to the values shown in Table 1. The sample of the obtained modified slaked lime was measured for its adhesion using the powder adhesion measuring device shown in FIGS. 1 and 2. In FIG. 1, the sample container is composed of two cylindrical frames, that is, a cylindrical upper frame 1 and a lower frame 2 having a flange 8. The upper frame 1 is placed on the lower frame 2,
Plastic disk 3A with many holes at its bottom and filter paper 4
After putting A, the slaked lime of sample 5 is evenly put in and lightly sliced, and a filter paper 4B and a plastic disc 3B having a large number of holes are placed on top thereof, and pressed with a piston 6 and a predetermined pressure is applied by a hydraulic press 7 with a hydraulic press 7. Apply W. Then, after releasing the pressure, it was incorporated into a measuring device as shown in FIG.
Water 11 is poured into the weight water container 20 and an upward tensile load W is applied thereto. When the upper frame 1 and the lower frame 2 separate and break, water injection is stopped at the same time, and the water container 20 and the water therein are stopped. The weight 11 and the broken upper sample 51 and the upper frame 1 are weighed together. The adhesion strength was determined by the following equation. Table 1 shows the obtained results.
Shown in Table 2 shows the characteristics of the processing operation of the samples in Table 1 and the low adhesion effect.

[0014]

(Equation 1)

[0015]

[Table 1]

[0016]

[Table 2]

[0017]

As described above in detail, the low-adhesive slaked lime of the present invention and the method for modifying the same are characterized by reducing the adhesion of slaked lime by adding quicklime and additives to slaked lime and heating the mixture. As a result, adhesion or solidification of the slaked lime to pipes, tank inner walls and the like during transportation and storage can be significantly reduced. Therefore, the present invention has an excellent effect that cleaning work for pipes and tanks can be reduced, and clogging of pipes and nozzles due to solidified substances can be prevented and stable work can be achieved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a sample container used in the present invention.

FIG. 2 is a sectional view showing a powder adhesion measuring device used in the present invention.

[Description of Signs] 1 Cylindrical upper frame 8 Flange 2 Cylindrical lower frame 9 Wire 3A Plastic board with through-hole (lower) 10 Fixing member 3B Plastic board with through-hole (upper) 11, 1
4 Water 4A Filter paper (bottom) 12A,
12B Bearing 4B Filter paper (upper) 13 Buret 5, 51, 52 Sample 20 Water container 6 Piston W Load 7 Hydraulic press

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-193997 (JP, A) JP-A-49-1007026 (JP, A) JP-A-2-34513 (JP, A) 8194 (JP, B2) Lime October 1977 No. 262 October 25, 1977 Published by the Japan Lime Association, pages 19, 21, 24 Lime Handbook August 31, 1992 Published by the Japan Lime Association, pages 217, 218 Journal of Powder Technology Research Vol. 7 NO. 5 Powder Technology Research Group October 1, 1970 Showa 27, pp. 31-34 (58) Fields investigated (Int. Cl. ⁶ , DB name) C01F 11/02 C04B 2/06

Claims (10)

(57) [Claims] 1. A composition comprising slaked lime, powdered lime and at least one additive selected from glycols, glycol ethers or ethanolamines, wherein the weight ratio of the slaked lime to the powdered lime is 98: 2 to 70. : 30
A modified low-adhesive slaked lime characterized by the following. 2. The modified low-adhesive slaked lime according to claim 1, wherein the glycol is at least one selected from ethylene glycol, diethylene glycol, triethylene glycol and tetraethylene glycol. 3. The method according to claim 1, wherein the glycol ether is at least one selected from ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether and triethylene glycol monoethyl ether. 2. The modified low-adhesive slaked lime according to 1. 4. The modified low-adhesion slaked lime according to claim 1, wherein the ethanolamine is at least one selected from monoethanolamine, diethanolamine and triethanolamine. 5. The addition amount of glycols, glycol ethers or ethanolamines diethylene glycol is 0.5 parts by weight or more based on the total of slaked lime and powdered lime.
The modified low-adhesion slaked lime according to any one of claims 1 to 4, wherein the content is 5.0 parts by weight. 6. The method according to claim 1, wherein the sum of diethylene glycol and triethylene glycol added simultaneously is 0.5 to 5.0 parts by weight based on the total of slaked lime and powdered lime. The modified low-adhesion slaked lime according to claim 2. 7. The weight ratio of slaked lime and powdered lime is 9
After adding and mixing at least one additive selected from glycols, glycol ethers or ethanolamines to the blend of 8: 2 to 70:30, heating the resulting mixture. Method of reforming slaked lime. 8. The addition amount of diethylene glycol, glycols, glycol ethers or ethanolamines, is 0.5% by weight to the total of slaked lime and powdered lime.
The method for modifying slaked lime according to claim 7, wherein the amount is 5.0 parts by weight. 9. The method for modifying slaked lime according to claim 7, wherein the heating temperature is maintained at 30 ° C. to 175 ° C. 10. The method for modifying slaked lime according to claim 7, wherein the heating time is 30 minutes to 100 hours.