KR100832225B1 - Method for manufcturing a reaction-delayed calcined lime using hydration reaction heat - Google Patents

Abstract

A method for preparing reaction-delayed quicklime using hydration reaction heat is provided to obtain reaction-delayed quicklime having excellent stability in a cost-efficient manner by using no heating instrument. A method for preparing reaction-delayed quicklime using hydration reaction heat comprises the steps of: mixing and agitating 100 parts by weight of quicklime particles having an average particle diameter of 0.005-5 mm with 0.5-5.0 parts by weight of water; and adding 0.1-5.0 parts by weight of a C12-C28 saturated fatty acid thereto, and mixing and agitating the mixture so that the whole surface of the quicklime particles is coated with the saturated fatty acid. Further, the saturated fatty acid is a stearin acid.

Description

METHODS FOR MANUFCTURING A REACTION-DELAYED CALCINED LIME USING HYDRATION REACTION HEAT}

1 is an explanatory diagram of a high speed mixer used in an embodiment.

<Description of the symbols for the main parts of the drawings>

1: Horizontal cylindrical mixing drum 2: Horizontal single axis drive

3: material inlet port 4: exhaust port

5: discharge gate 6: sputum shovel blade

7: chopper wing

The present invention relates to a method for producing reactive delayed quicklime using heat of hydration reaction. More specifically, the present invention economically produces a reactive delayed quicklime having excellent stability in which the entire surface of the quicklime particles is covered with saturated fatty acid, without using a heating facility, using the heat of reaction between quicklime and water. The present invention relates to a method for producing reactive delayed quicklime using heat of hydration reaction.

Quicklime is not only used in the manufacture of carbides, but also for conventional industrial applications, such as chemical raw materials using its strong reactivity, lining materials for industrial furnace walls using high melting points, agriculture and construction. In addition, in recent years, as a measure for environmental conservation, it has begun to be used for polluted soil purification treatment and the like, and demand is rapidly increasing. Limestone (main component calcium carbonate) calculated in various parts of Korea is calcined at high temperature by a continuous or batch type, and is mass-produced.

Quicklime is very hygroscopic, and it is necessary to seal it completely by blocking contact with moisture during storage. Moreover, since quicklime is too reactive, there are many uses which should suppress and use reactivity. Such detoxification of harmful substances requires quicklime reacting slowly under specific conditions. For example, it is possible to safely harm the waste materials, especially used oils and oily substances by a simple method, and have a surface activity and delay the reaction with water to oil or polymer organic waste materials. A method of adding calcium oxide treated with a substance to be added and reacting the calcium oxide absorbing the waste material with calcium in a stoichiometric amount until it becomes calcium hydroxide (Patent Document 1) is proposed.

Background Art Conventionally, reactive delayed quicklime has been produced as quicklime particles in which agglomerates of quicklime are pulverized in the presence of a reactive delaying agent such as a surfactant, and the coating by the reactive delaying agent is formed. For example, as a rational production method of powdery reaction delayed quicklime with less nonuniformity in terms of reaction delayability, a surfactant or fat or oil is added to the quicklime that has been coarsely pulverized to a predetermined particle size. A method for producing a powdery reactive delayed quicklime, which is added at a liquefaction temperature or higher than an evaporation temperature of an active agent and at the same time, finely pulverizes the quicklime added with the surfactant or fat or oil to form a powder (Patent Document 2). However, with this manufacturing method, it is difficult to manufacture a product having a uniform reaction delay function. In addition, in the case of producing reactive delayed quicklime using commercially available quicklime as raw material, calcined heat of limestone cannot be used, and it is necessary to heat quicklime or the product maker.

First, the present inventors can economically produce reactive delayed quicklime whose surface of coarse particles of quicklime is covered with a higher fatty acid and in which the reaction rate when contacted with water is delayed by simple equipment. As a method, coarsely pulverized quicklime is put into a chute, high fatty acid is added to the chute, and quicklime falling from the chute is received by a belt conveyor alternately provided with a plurality of baffles on both sides. In addition, a method for producing reactive delayed quicklime which coats the surface of coarse limestone with high fatty acid is proposed, and stearic acid heated and melted at 75 ° C in a spray form is added to coarse lime of calcined lime at 85 ° C after firing. An example was shown (patent document 3). In this example, the heat of calcining limestone is used, but heating of quicklime particles is necessary when the quicklime coating is not performed immediately after firing. Further, eventually, an apparatus for melting higher fatty acids and an apparatus for spraying are required.

The surface of the quicklime is covered by fatty acids or derivatives in a partially exposed state, and the quicklime is liable to come into contact with moisture in the soil, and a sufficient hydration reaction is likely to occur in a short time, and a sufficient compressive strength is easily expressed even after replenishing the soil. As a method for producing delayed quicklime for soil improving agent, a powdery or granular quicklime is mixed with fatty acids or derivatives in an amount in the range of 0.1 to 5% by weight relative to the quicklime, and then 1 to 10 with respect to the quicklime in the mixture. A method of preparing delayed quicklime for soil improver is added, in which water in an amount in the range of weight% is added, and the water-containing mixture is mixed at a temperature of 70 ° C. or higher. After stearic acid is added to the quicklime and mixed firstly, water is added. By second mixing, an exotherm due to a hydration reaction can be seen, and an example in which the temperature of the mixture has risen to about 110 ° C. (Patent Document 4). According to this method, the heat of reaction between quicklime and water can be used to raise the temperature of the mixture of quicklime and fatty acids, and the energy required for heating the mixture can be omitted, and thermal energy can be saved. However, by this method, the entire surface of the quicklime particles cannot be covered with fatty acids or the like, and the quicklime surface is partially exposed. There are also applications where the surface of quicklime is partially exposed, the contact with moisture in the soil is easy, and there is a need for easy hydration reaction to occur in a short time, but for the purpose of reacting quicklime with harmful substances in contaminated soil, Inadequate In order to disperse harmful substances in the soil and adsorb to the reactive delayed quicklime particles, the reaction between quicklime and water until the polluted soil and the reactive delayed quicklime are uniformly mixed and the hazardous substances are absorbed by the reactive delayed quicklime. It is necessary to prevent this from happening. As a precondition, the entire surface of the quicklime particles needs to be covered with a reaction retardant. After sufficient stirring and mixing with harmful substances such as contaminated soil, the surface of the quicklime particles is damaged or damaged until the surface is damaged. After addition and mixing, at the stage where the reaction retardant is decomposed or peeled off by the microorganisms in the ground, the surface of the quicklime particles starts to slowly react with water under the condition that the harmful substances absorbed by the reaction retardant and the quicklime coexist. It is important to do.

[Patent Document 1]

Japanese Patent Application Laid-Open No. 50-32075

[Patent Document 2]

Japanese Patent Application Laid-Open No. 9-169551

[Patent Document 3]

Japanese Patent Application Laid-Open No. 2001-240436

[Patent Document 4]

Japanese Patent Application Laid-Open No. 10-60431

The present invention relates to a heat of hydration reaction which can economically produce a reaction-delayable quicklime having excellent stability in which the entire surface of quicklime particles is covered with saturated fatty acid, without using a heating facility, using the heat of reaction between quicklime and water. It is an object of the present invention to provide a method for preparing a reaction delayed quicklime using the above.

MEANS TO SOLVE THE PROBLEM As a result of earnestly researching in order to solve the said subject, as a result of adding the water to quicklime particle and stirring-mixing, it heated up quicklime particle by the heat of reaction of quicklime and water, and then has a C12-C28 By adding a saturated fatty acid and stirring and mixing, it has been found that it is possible to cover the entire surface of the quicklime particles with saturated fatty acids without leaving exposed portions on the quicklime surface, and to complete the present invention based on this knowledge. I have reached.

That is, the present invention,

(1) To 100 parts by weight of quicklime particles having an average particle size of 0.005 to 5 mm, 0.5 to 5.0 parts by weight of water is added and stirred and mixed, and then 0.1 to 5.0 parts by weight of saturated fatty acids having 12 to 28 carbon atoms are added and stirred and mixed. Method for producing a reaction delayed quicklime using heat of hydration, characterized in that the entire surface of the quicklime particles is coated with saturated fatty acid,

(2) Method of producing delayed reaction quicklime using the heat of hydration reaction as described in (1), in which the amount of water and the rate of addition are adjusted so that the temperature of quicklime particles becomes higher than the melting point of saturated fatty acid when water is added and stirred and mixed.

(3) A method for producing reactive delayed quicklime using the heat of hydration reaction according to (1) or (2), in which 1.5 to 3.5 parts by weight of water is added within 60 seconds to 100 parts by weight of quicklime particles;

(4) A method of producing delayed quicklime, using hydration reaction heat according to (1), to add 0.3 to 2.5 parts by weight of C14-20 linear saturated fatty acid to 100 parts by weight of quicklime particles, and

(5) A method for producing reactive delayed quicklime using the heat of hydration reaction according to (1) or (4), wherein the saturated fatty acid is stearic acid;

To provide.

According to the manufacturing method of the reaction delayed quicklime using the heat of hydration reaction of the present invention, the entire surface of the quicklime particles is covered with saturated fatty acid, and the reaction delayed quicklime with a large reaction delay is used without using the heating device of quicklime particles. It can be manufactured economically. The reaction delayed quicklime produced by the method of the present invention has a good reaction delay, so that it is mixed with contaminated soils containing harmful substances, and the long-term reaction delays in which decomposition starts after the harmful substances are adsorbed on the quicklime particles. It can be used very suitably for the application | requirement to which sex is required.

Best Mode for Carrying Out the Invention

In the production method of the reaction delayed quicklime using the heat of hydration reaction of the present invention, 0.5 to 5.0 parts by weight of water is added to 100 parts by weight of the quicklime particles having an average particle diameter of 0.005 to 5 mm, followed by stirring and mixing. 0.1 to 5.0 parts by weight of saturated fatty acid was added and stirred, and the entire surface of the quicklime particles was coated with saturated fatty acid.

The average particle diameter of quicklime particle used for this invention is 0.005-5 mm, More preferably, it is 0.05-4 mm, More preferably, it is 0.5-3 mm. If the average particle size of the quicklime particles is less than 0.005 mm, the oscillation is caused by fine particles, the handling efficiency is lowered, and the surface area per unit weight is increased to cover the entire surface of the quicklime particles, thereby increasing the amount of saturated fatty acid required. There is a concern. If the average particle diameter of quicklime particles exceeds 5 mm, the surface area per unit weight decreases, and there is a concern that sufficient reaction rate may not be obtained in the treatment of soil stability, soil improvement, removal of harmful substances, and the like. Quicklime is produced by calcining limestone, which contains calcium carbonate as its main ingredient, and has a variety of average particle sizes and particle size distributions for various uses such as steel, chemical industry, construction, pollution prevention, fertilizer, and pesticides. Since it is commercially available, the product which has a suitable average particle diameter can be selected suitably from a commercial item.

   In the method of the present invention, the apparatus for stir-mixing quicklime and water, and the apparatus for stir-mixing quicklime and water, and then adding a saturated fatty acid to stir-mixing are not particularly limited. For example, a horizontal cylindrical mixer, V-type mixer with stirring blade, double cone mixer, swinging mixer, single-axis ribbon mixer, double shaft paddle mixer, rotary sputum mixer, two-axis planetary mixer, conical screw mixer, high speed stirring mixer, rotary disk type A mixer, a rotating container mixer with a roller, a rotating container mixer with a stirring, a high speed elliptic rotor type mixer, an airflow stirring mixer, an agitator type mixer, etc. are mentioned. Among them, a rotary sputum mixer, a high speed stirrer mixer, a rotating vessel mixer with agitation, etc., which can achieve a high mixing dispersion degree with a short stirring mixing time, can be suitably used.

In the method of this invention, 0.5-5.0 weight part of water with respect to 100 weight part of quicklime particle | grains, More preferably, 1.5-3.5 weight part is added and stirred and mixed. When water is added and stirred and mixed with quicklime, quicklime reacts with water to generate calcined lime, and heat of reaction of 15.2 kcal per mole is generated as shown in the following equation.

CaO + H ₂ O → Ca (OH) ₂ + 15.2 kcal

This heat of reaction increases the temperature of the quicklime particles, and reaches the melting point of the saturated fatty acid added next. When the amount of water added to 100 parts by weight of the quicklime particles is less than 0.5 parts by weight, the amount of heat generated for reaction is insufficient, and the temperature of the quicklime particles may not sufficiently increase. When the amount of water added to 100 parts by weight of quicklime particles exceeds 5.0 parts by weight, heat of reaction is generated more than necessary, and quicklime is further calcined more than necessary, and the effective amount of reactive delayed quicklime obtained may be lowered.

In the method of the present invention, when water is added to the quicklime particles and mixed with stirring, it is preferable to adjust the amount of water added so that the temperature of the quicklime particles becomes higher than the melting point of the saturated fatty acid to be added next. When stirring and mixing quicklime particles and water using a stirring mixer, the temperature at which quicklime particles are reached is influenced by the temperature of the quicklime particles and water as raw materials, the temperature of external air, the temperature of the vessel of the stirring mixer, and the like. When the temperature of the container of raw materials, external air, and stirring mixer is low, it is preferable to increase the amount of water to be added to increase the amount of reaction heat generated, so that the temperature of the quicklime particles is adjusted to be above the melting point of saturated fatty acid. In addition, even in the manufacture of the same batch, in the manufacture of the first batch, the temperature of the container is almost equal to the temperature of the outside air, but in the manufacture of the next batch, since the container is warmed in the manufacture of the first batch, Can reduce the amount of water. When water is added more than necessary, quicklime turns into calcined more than necessary, and since the effective amount of reactive delayed quicklime obtained falls, it is preferable to adjust the addition amount of water according to environmental conditions.

In the method of the present invention, when water is added to the quicklime particles and mixed with stirring, it is preferable to adjust the rate of addition of water so that the temperature of the quicklime particles becomes higher than the melting point of the saturated fatty acid to be added next. If the rate of addition of water is delayed and the time required for the addition of water is long, the amount of heat lost by heat dissipation from the quicklime particles is increased before the generation of heat of reaction due to the reaction of quicklime particles and water is completed. The amount of increases. The time required for adding water to quicklime particles is preferably within 60 seconds, more preferably within 30 seconds, and even more preferably within 10 seconds.

In the method of the present invention, 0.5 to 5.0 parts by weight of water is added and stirred and mixed with 100 parts by weight of quicklime particles, and then 0.1 to 5.0 parts by weight of saturated fatty acid having 12 to 28 carbon atoms is added and stirred and mixed, and the total of the quicklime particles The surface is covered with saturated fatty acid. In the method of this invention, it is more preferable to add 0.3-2.5 weight part of C14-C20 linear saturated fatty acids with respect to 100 weight part of quicklime particles.

Examples of the saturated fatty acid having 12 to 28 carbon atoms used in the method of the present invention include lauric acid, myristic acid, palmitic acid, stearic acid and arachidic acid. straight-chain saturated fatty acids such as acid, behenic acid, lignoceric acid, cerotinic acid, and montanic acid, 12-methyltridecanoic acid, 14-methylpentadecane Acid, 16-methylheptadecanoic acid, 17-methyloctadecanoic acid, 2-methylicosanoic acid, 2-methyldocoic acid, 2-methyltricoic acid, 3-methyltricoic acid, 22-methyltricoic acid, 20-ethyldoco Acid, 2-methyltetracoic acid, 3-methyltetracoic acid, 23-methyltetracoic acid, 24-methylheptacoic acid, 2-ethyltetracoic acid, 2-butyldocosanic acid, 2-hexylicosanic acid, 2 And branched saturated fatty acids such as methylhexanoic acid. These saturated fatty acids can be used individually by 1 type, the mixture of 2 or more types of saturated fatty acids can be used, and the mixture containing a small amount of unsaturated fatty acids can be used. Among these, straight-chain saturated fatty acids can be easily produced from natural products as raw materials, have a relatively high melting point, and can be used suitably, and stearic acid can be particularly suitably used.

In the method of the present invention, if the carbon number of the saturated fatty acid to be added is less than 12, the melting point of the saturated fatty acid is low, and there is a concern that it is difficult to stably cover the entire surface of the quicklime particles. When the carbon number of the saturated fatty acid to add exceeds 28, the melting point of saturated fatty acid is high, and since the temperature of quicklime particle rises above the melting point of saturated fatty acid, there exists a possibility that the quantity of water added may become too large. If the amount of saturated fatty acid to be added is less than 0.1 part by weight with respect to 100 parts by weight of quicklime particles, the amount of saturated fatty acids is insufficient, making it difficult to cover the entire surface of the quicklime particles, and the part exposed on the surface of the quicklime particles remains. There is a concern. The amount of saturated fatty acid to be added can sufficiently cover the entire surface of the quicklime particles to 5.0 parts by weight or less with respect to 100 parts by weight of quicklime particles, and when the amount of saturated fatty acids to be added exceeds 5.0 parts by weight with respect to 100 parts by weight of quicklime particles. The saturated fatty acid film covering the quicklime particles becomes too thick, so that the reaction delay is remarkably increased, or saturated fatty acids that do not contribute to the coating of the quicklime particles may be mixed in the reactive delayed quicklime.

In the method of the present invention, when water is added to the quicklime particles and stirred and mixed, and then saturated fatty acid is added and stirred and mixed, in the first step, heat of reaction is generated by the chemical reaction between the quicklime particles and water and the temperature of the quicklime particles is increased. The melting point of saturated fatty acid rises above it, and in the second step, saturated fatty acid melts and becomes a liquid, and evenly covers the entire surface of quicklime particles. When the temperature decreases and falls below a titer, it covers the entire surface. Solidify in one state. For this reason, the entire surface of the quicklime particles is covered with solidified saturated fatty acid, and the quicklime particles have excellent reaction lag. On the other hand, when saturated fatty acid is added to the quicklime particles and stirred and mixed, then water is added to the mixed solution to stir-mix and the physical reaction of the quicklime particles and the water is carried out by chemical reaction of the quicklime particles and melting of saturated fatty acids and the coating of the quicklime particles by molten saturated fatty acid Since the change occurs in parallel, it becomes difficult to uniformly cover the entire surface of the quicklime particles, and it is considered that portions exposed on the surfaces of the quicklime particles remain.

The saturated fatty acid used in the method of the present invention does not need to be of high purity, and a saturated fatty acid containing an unsaturated fatty acid or a mixture of saturated fatty acids having different carbon numbers can be used. For example, a product obtained by cold pressing fatty acids obtained by decomposing tallow and removing liquid acid has a stearic acid as a main component, and a small amount of unsaturated fatty acids such as oleic acid and a significant amount of carbon number such as myristic acid and palmitic acid. Although saturated fatty acid is contained, such a mixture can be used as saturated fatty acid.

In the method of the present invention, whether or not the entire surface of the quicklime particles is covered with saturated fatty acid can be determined by observing the state change when the quicklime particles are immersed in water. For example, when the reaction-delayed quicklime is immersed in purified water at 25 ° C., if the entire surface of the quicklime particles is covered with saturated fatty acid, no change of state is observed after 30 minutes. If there is a part exposed on the surface of the particle, the shape of the particle starts to collapse in 1 to 5 minutes, and after 30 minutes, the shape is almost maintained in its original shape. When the reaction delayed quicklime is immersed in purified water at 25 ° C., when the entire surface of the quicklime particles is covered with saturated fatty acid, the pH of the water after 30 minutes is about 0.75. If there is a part exposed to the surface of the water, the pH of water rises rapidly in 1 to 5 minutes.

<Example>

Although an Example is given to the following and this invention is demonstrated in detail below, this invention is not limited at all by these Examples.

In addition, in the Example and the comparative example, the horizontal cylindrical mixing drum 1 shown in FIG. 1, the horizontal uniaxial drive part 2, the material input port 3, the exhaust port 4, the discharge gate 5, and the phlegm type | mold High speed mixer (Taiheiyo-Kikou Co., Ltd., Plow Mix Mixer) equipped with floating diffusion mixing mechanism by shovel blade 6 and high speed shear dispersion mechanism by chopper blade 7 ( Brand name) WB-75].

Reference Example 1

35 kg of quicklime (JIS R 9001, Special Issue) having a particle diameter of 0.5 to 2.0 mm was added to a high speed mixer, and stirred and mixed for 1 minute with a spindle 167 min ⁻¹ and a chopper 3,000 min ⁻¹ . At this time, the internal temperature of the mixing drum was 17 ℃. Next, 1.050 kg of water was added for 8 seconds while stirring mixing was continued. When the addition of water was completed, the internal temperature of the mixing drum was 86 ° C, and after 81 minutes, it was 81 ° C, after 2 minutes, 69 ° C, after 3 minutes, 64 ° C, and after 4 minutes, 61 ° C.

Example 1

35 kg of quicklime (JIS R 9001, Special Issue) having a particle diameter of 0.5-2.0 mm was added to the high speed mixer, and the mixture was stirred and mixed for 1 minute with a spindle 167 min ^-1 and a chopper 3,000 min ^-1 . At this time, the internal temperature of the mixing drum was 24 ℃. Next, 1.050 kg of water was added for 8 seconds while continuing stirring, and stirring and mixing were continued for 1 minute, and the internal temperature of the mixing drum became 95 degreeC via the maximum temperature of 108 degreeC.

While continuing stirring, 0.350 kg of industrial stearic acid (66% by weight of stearic acid, 32% by weight of palmitic acid, 1% by weight of myristic acid, 1% by weight of arachic acid) was added, and stirring and mixing were continued. Each time one minute passed from the end of the addition, the internal temperature of the mixing drum was recorded and the quicklime particles were sampled.

The internal temperature of the mixed drum was 80 ° C. after 1 minute, 76 ° C. after 2 minutes, 73 ° C. after 3 minutes, 70 ° C. after 4 minutes, and 69 ° C. after 5 minutes. Each 10 g of quicklime particles coated with five samples of stearic acid sampled were put in 200 mL of purified water at 25 ° C., respectively, and the state after 1 minute, 5 minutes, 10 minutes and 30 minutes was observed. In all of the five samples, no change of state was observed after 30 minutes, and the entire surface of the quicklime particles was covered with stearic acid, and it was confirmed that the sample had excellent reaction delay.

In addition, in a constant temperature room at a temperature of 20 ° C, 10 g of quicklime particles sampled 3 minutes after the end of stearic acid addition were added to 200 mL of purified water in a beaker, and the pH and water temperature were measured every 5 minutes. PH of the purified water before injecting quicklime particle was 7.00, and the water temperature was 19.7 degreeC. The quicklime particles were added and stirred, and when 30 minutes had elapsed, the pH of the water rose to 7.75, but the water temperature was kept at 19.7 ° C during that time. pH rises 0.75, but since the water temperature does not rise, it turns out that reaction of quicklime particle and water only occurs very little. Table 1 shows the measured pH and water temperature.

Elapsed time (minutes) pH Water temperature (℃) 0 (purifier) 7.00 19.7 5 7.12 19.7 10 7.14 19.7 15 7.35 19.7 20 7.48 19.7 25 7.52 19.7 30 7.75 19.7

Example 2

The same operation as in Example 1 was carried out except that the amount of water added to 35 kg of quicklime was 0.700 kg, and the time required for adding water was 5.5 seconds.

When quicklime was stirred and mixed in the mixing drum for 1 minute, the internal temperature of the mixing drum was 26 ° C. Next, 0.700 kg of water was added for 5.5 second, continuing stirring mixing, and it stirred continuously for 1 minute, and the internal temperature of the mixing drum became 80 degreeC via the maximum temperature of 86 degreeC.

While stirring and stirring continued, 0.350 kg of industrial stearic acid same as Example 1 was added, stirring mixing was continued, and each time passed one minute from the end of stearic acid addition, the internal temperature of the mixing drum was recorded and the quicklime particles were sampled. It was.

The internal temperature of the mixed drum was 71 ° C. after 1 minute, 69 ° C. after 2 minutes, 67 ° C. after 3 minutes, 66 ° C. after 4 minutes, and 66 ° C. after 5 minutes. 100 g of each quicklime particle coated with 5 points of stearic acid sampled was charged into 20 mL of purified water at 25 ° C., respectively, and the state after 1 minute, 5 minutes, 10 minutes and 30 minutes was observed. In all of the five samples, no change of state was observed after 30 minutes, and the entire surface of the quicklime particles was covered with stearic acid, and it was confirmed that the sample had excellent reaction delay.

Example 3

The same operation as in Example 1 was carried out except that 0.700 kg of water was added to 35 kg of quicklime for 5.5 seconds, and 0.420 kg of stearic acid was added after 30 seconds after the addition of water was completed.

When quicklime was stirred and mixed in the mixing drum for 1 minute, the internal temperature of the mixing drum was 31 ° C. Next, 0.700 kg of water was added in 5.5 second, continuing stirring mixing, and stirring mixing was continued for 30 second, and the internal temperature of the mixing drum became 91 degreeC via the maximum temperature of 86 degreeC.

While stirring and stirring continued, 0.420 kg of industrial stearic acid same as Example 1 was added, stirring mixing was continued, and each minute passed from the end of stearic acid addition, the internal temperature of the mixing drum was recorded, and the quicklime particles were sampled. It was.

The internal temperature of the mixed drum was 73 ° C. after 1 minute, 70 ° C. after 2 minutes, 67 ° C. after 3 minutes, 66 ° C. after 4 minutes, and 65 ° C. after 5 minutes. 100 g of each quicklime particle coated with 5 points of stearic acid sampled was put in 200 mL of purified water at 25 ° C., respectively, and the state after 1 minute, 5 minutes, 10 minutes and 30 minutes was observed. In all of the five samples, no change of state was observed after 30 minutes, and the entire surface of the quicklime particles was covered with stearic acid, and it was confirmed that the sample had excellent reaction delay.

Example 4

The same operation as in Example 1 was repeated except that the amount of quicklime added to the high speed mixer was 42 kg, 0.842 kg of water was added to the quicklime for 6 seconds, and 0.462 kg of stearic acid was added after 30 seconds after the addition of water was completed. Was run.

When quicklime was stirred and mixed in the mixing drum for 1 minute, the internal temperature of the mixing drum was 27 ° C. Next, 0.842 kg of water was added for 6 seconds while continuing stirring mixing, and stirring mixing was continued for 30 seconds, and the internal temperature of the mixing drum became 96 degreeC via the maximum temperature of 98 degreeC.

While stirring and stirring continued, 0.462 kg of industrial stearic acid same as Example 1 was added, stirring mixing was continued, and each time passed one minute from the end of stearic acid addition, the internal temperature of the mixing drum was recorded and the quicklime particles were sampled. It was.

The internal temperature of the mixed drum was 81 ° C. after 1 minute, 77 ° C. after 2 minutes, 75 ° C. after 3 minutes, 74 ° C. after 4 minutes, and 73 ° C. after 5 minutes. Each 10 g of quicklime particles coated with 5 points of stearic acid sampled were put into 20 mL of purified water at 25 ° C., respectively, and the state after 1 minute, 5 minutes, 10 minutes, and 30 minutes was observed. In all of the five samples, no change of state was observed after 30 minutes, and the entire surface of the quicklime particles was covered with stearic acid, and it was confirmed that the sample had excellent reaction delay.

Comparative Example 1

35 kg of quicklime and 0.350 kg of industrial stearic acid, which were the same as in Example 1, were charged at the same time into a high-speed mixer, followed by stirring and mixing for 1 minute at a spindle of 167 min ⁻¹ and a chopper of 3,000 min ⁻¹ . At this time, the internal temperature of the mixing drum was 24 ℃. Next, 1.050 kg of water was added for 8 seconds while stirring and mixing was continued, and each time 1 minute passed from the addition of water, the internal temperature of the mixing drum was recorded, and the quicklime particle was sampled.

The internal temperature of the mixed drum was 99 ° C. after 1 minute, 85 ° C. after 2 minutes, 80 ° C. after 3 minutes, 77 ° C. after 4 minutes, and 75 ° C. after 5 minutes. Each 10 g of quicklime particles coated with five samples of stearic acid sampled were put in 200 mL of purified water at 25 ° C., respectively, and the state after 1 minute, 5 minutes, 10 minutes and 30 minutes was observed. After five minutes, the shape of the particles began to collapse after about one minute, and after 10 minutes, it was confirmed that the surface of the quicklime particles was at least partially exposed without maintaining the original shape.

Comparative Example 2

The same operation as in Comparative Example 1 was carried out except that the amount of water added to the mixture of 35 kg of quicklime and 0.350 kg of industrial stearic acid was 0.700 kg, and the time required for adding water was 5 seconds.

The internal temperature of the mixed drum was 78 ° C. after 1 minute of water addition, 69 ° C. after 2 minutes, 65 ° C. after 3 minutes, 63 ° C. after 4 minutes, and 62 ° C. after 5 minutes. 100 g of each quicklime particle coated with 5 points of stearic acid sampled was put in 200 mL of purified water at 25 ° C., respectively, and the state after 1 minute, 5 minutes, 10 minutes and 30 minutes was observed. The sample of 1 minute after the end of the addition of water and the sample of 2 minutes after the addition of water began to collapse the shape of the particles after 1 minute, and remained almost intact after 10 minutes. In addition, after 3 minutes, 4 minutes, and 5 minutes after the end of the addition of water, the shape of the particles began to collapse after 5 minutes, and the original shape was almost maintained after 30 minutes. As a result, when water was added to the mixture of quicklime and stearic acid and stirred and mixed, it was confirmed that the reaction delayed quicklime obtained obtained at least partially the surface of quicklime particles.

The mixing conditions of the raw materials of Examples 1 to 4 are shown in Table 2, the temporal change of the internal temperature of the mixing drum and the reaction delay of the obtained quicklime particles are shown in Table 3, and the mixing conditions of the raw materials of Comparative Examples 1 to 2 are shown in Table 4. The change in the internal temperature of the mixed drum over time and the reaction delay of the obtained quicklime particles are shown in Table 5.

Quicklime input (kg) Amount of water added (kg) Time (seconds) during addition of water-stearic acid Temperature before and after addition of water (℃) Stearic acid addition amount (kg) Example 1 35 1.050 60 24 → 108 → 95 0.350 Example 2 35 0.700 60 26 → 86 → 80 0.350 Example 3 35 0.700 30 31 → 86 → 91 0.420 Example 4 42 0.842 30 27 → 98 → 96 0.462

Time after adding stearic acid (minutes) One 2 3 4 5 Example 1 Temperature (℃) 80 76 73 70 69 Response delay ○ ○ ○ ○ ○ Example 2 Temperature (℃) 71 69 67 66 66 Response delay ○ ○ ○ ○ ○ Example 3 Temperature (℃) 73 70 67 66 65 Response delay ○ ○ ○ ○ ○ Example 4 Temperature (℃) 81 77 75 74 73 Response delay ○ ○ ○ ○ ○

Quicklime input (kg) Stearic Acid Input (kg) Amount of water added (kg) Comparative Example 1 35 0.350 1.050 Comparative Example 2 35 0.350 0.700

Number of minutes after addition of water One 2 3 4 5 Comparative Example 1 Temperature (℃) 99 85 80 77 75 Response delay × × × × × Comparative Example 2 Temperature (℃) 78 69 65 63 62 Response delay × × △ △ △

As can be seen from Tables 2 to 5, in Examples 1 to 4 and Comparative Examples 1 to 2, the internal temperature of the mixing drum of the high speed mixer experienced almost the same time course of change. However, the quicklime particles obtained in Examples 1 to 4 have excellent reaction delay characteristics, whereas the quicklime particles obtained in Comparative Examples 1 to 2 have poor reaction delay characteristics. As a result, when the quicklime particles, water and stearic acid are mixed, the quicklime particles and water are first mixed and heated by the reaction heat, and then stearic acid is added to cover the entire surface of the quicklime particles with stearic acid. When the reaction delay can be obtained, when quicklime particles and stearic acid are mixed, water is added and the temperature is raised by the heat of reaction. At least partially exposed portions remain on the surface of the quicklime particles, and sufficient reaction delay is achieved. You can see that it can not be obtained.

According to the manufacturing method of the reaction delayed quicklime using the heat of hydration reaction of the present invention, the entire surface of the quicklime particles is covered with saturated fatty acid, and the reaction delayed quicklime with a large reaction delay is used without using the heating device of quicklime particles. It can be manufactured economically. The reaction delayed quicklime produced by the method of the present invention has a good reaction delay, so that it is mixed with contaminated soils containing harmful substances, and the long-term reaction delays in which decomposition starts after the harmful substances are adsorbed on the quicklime particles. It can be used very suitably for the application | requirement to which sex is required.

Claims (5)

To 100 parts by weight of quicklime particles having an average particle diameter of 0.005 to 5 mm, 0.5 to 5.0 parts by weight of water are added and stirred and mixed, followed by stirring and addition to 0.1 to 5.0 parts by weight of saturated fatty acid having 12 to 28 carbon atoms, A process for producing a reaction delayed quicklime using heat of hydration, characterized in that the entire surface is covered with saturated fatty acid. The method of claim 1, A method of producing delayed reaction quicklime using heat of hydration, wherein the amount of water added and the rate of addition are adjusted so that the temperature of quicklime particles becomes higher than the melting point of saturated fatty acids when water is added and stirred and mixed. The method according to claim 1 or 2, A method for producing a reaction delayed quicklime using heat of hydration, wherein 1.5 parts by weight to 3.5 parts by weight of water is added to 60 parts by weight of quicklime particles. The method of claim 1, 0.3 to 2.5 parts by weight of straight chain saturated fatty acid having 14 to 20 carbon atoms is added to 100 parts by weight of quicklime particles. The method according to claim 1 or 4, Saturated fatty acid is stearic acid, characterized in that the production of reaction delayed quicklime using heat of hydration reaction.

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