阅读说明：本技术 一种新型高强度氢氧化钙型二氧化碳吸收剂及其制备方法 (Novel high-strength calcium hydroxide type carbon dioxide absorbent and preparation method thereof ) 是由 邹晓轩 石海金 周文志 于 2019-07-05 设计创作，主要内容包括：本发明公开了一种新型高强度氢氧化钙型二氧化碳吸收剂,由以下重量份数的原料组分制备而成：氢氧化钙50～100份,氢氧化钠0～5份,氢氧化钾0～5份,无机保湿剂1～5份,乙烯醋酸乙烯共聚物粉1～5份,无机粘合剂1～5份,PH指示剂0.01～1份,去离子水10～20份。本发明还提供了本发明提供的一种一种新型高强度氢氧化钙型二氧化碳吸收剂制备方法,最终本发明制得的高强度氢氧化钙型二氧化碳吸收剂,二氧化碳吸收率高,且内部粘结性能强且持久,在很强的冲击条件下及长时间保存后都不易产生粉末,可用于医院麻醉循环系统中吸收人体呼出的二氧化碳以及传统钠石灰使用的领域,如化学分析、煤矿、潜水、航天等。(The invention discloses a novel high-strength calcium hydroxide type carbon dioxide absorbent which is prepared from the following raw material components in parts by weight: 50-100 parts of calcium hydroxide, 0-5 parts of sodium hydroxide, 0-5 parts of potassium hydroxide, 1-5 parts of an inorganic humectant, 1-5 parts of ethylene vinyl acetate copolymer powder, 1-5 parts of an inorganic binder, 0.01-1 part of a pH indicator and 10-20 parts of deionized water. The high-strength calcium hydroxide type carbon dioxide absorbent prepared by the invention has high carbon dioxide absorption rate, strong and durable internal bonding performance, is not easy to generate powder under strong impact conditions and after long-time storage, and can be used in fields of absorbing carbon dioxide exhaled by a human body in an anesthesia circulatory system of a hospital and using traditional soda lime, such as chemical analysis, coal mine, diving, aerospace and the like.)

1. A novel high-strength calcium hydroxide type carbon dioxide absorbent is characterized in that: the water-based paint is prepared from the following raw materials, by weight, 50-100 parts of calcium hydroxide, 0-5 parts of sodium hydroxide, 0-5 parts of potassium hydroxide, 1-5 parts of an inorganic humectant, 1-5 parts of ethylene-vinyl acetate copolymer powder, 1-5 parts of an inorganic binder, 0.01-1 part of a pH indicator and 10-20 parts of deionized water; wherein the inorganic binder is sodium aluminosilicate or white cement.

2. The novel high-strength calcium hydroxide-type carbon dioxide absorbent according to claim 1, wherein: 70-80 parts of calcium hydroxide, 0-3 parts of sodium hydroxide, 0-3 parts of potassium hydroxide, 2-3 parts of an inorganic humectant, 2-4 parts of an ethylene vinyl acetate copolymer, 1-5 parts of an inorganic binder, 0.01-1 part of a pH indicator and 10-20 parts of deionized water.

3. The novel high-strength calcium hydroxide-type carbon dioxide absorbent according to claim 1, wherein: the ethylene-vinyl acetate copolymer is powder, the melting point is 90-120 ℃, the melt index is 40-100 g/10min, and the particle size of the powder is more than 50 meshes.

4. The novel high-strength calcium hydroxide-type carbon dioxide absorbent according to claim 1, wherein: the inorganic humectant adopts one of magnesium chloride or calcium chloride; the PH indicator adopts one of methyl violet or Dandan yellow.

5. The novel high-strength calcium hydroxide-type carbon dioxide absorbent according to claim 1, wherein: the inorganic binder is sodium aluminosilicate.

6. A method for producing a novel high-strength calcium hydroxide-type carbon dioxide absorbent according to any one of claims 1 to 5, characterized in that: comprises the following steps of (a) carrying out,

(1) pre-mixing part of sodium hydroxide and potassium hydroxide with all other raw materials, and ball-milling for a period of time in a ball mill;

(2) adding a proper amount of deionized water, and pressing into particles, tablets or strips with a preset shape;

(3) drying for a period of time;

(4) preparing the residual sodium hydroxide or potassium hydroxide into a water solution with the concentration of 3-6 mol/L, uniformly spraying the water solution on the surface of a product, and drying for a period of time;

(5) and finally, hydrating to a certain water content to obtain a finished product.

7. The method for preparing a novel high-strength calcium hydroxide type carbon dioxide absorbent according to claim 6, wherein: the ball milling time in the step (1) is 20-90 min.

8. The method for preparing a novel high-strength calcium hydroxide type carbon dioxide absorbent according to claim 6, wherein: and (3) in the step (2), pressing and forming into granules, tablets or strips with a preset shape by a die pressing method.

9. The method for preparing a novel high-strength calcium hydroxide type carbon dioxide absorbent according to claim 6, wherein: and (3) drying for 5-15 min at 120-140 ℃ in an oven.

10. The method for preparing a novel high-strength calcium hydroxide type carbon dioxide absorbent according to claim 6, wherein: the weight ratio of part of sodium hydroxide to the total weight of sodium hydroxide in the step (1) is 0-0.67: 1, and the weight ratio of part of potassium hydroxide to the total weight of potassium hydroxide in the step (1) is 0-0.67: 1; and (4) drying for 5-15 min at 120-140 ℃ by using an oven.

Technical Field

The invention relates to the technical field of absorbents, in particular to a novel high-strength calcium hydroxide type carbon dioxide absorbent and a preparation method thereof.

Background

In many fields of production and science, such as aerospace, involvement, medicine, chemical engineering, metallurgy, etc., it is necessary to remove carbon dioxide from gases, and therefore, carbon dioxide absorbents have been widely used in fields such as gas analysis, pure gas preparation, and clinical medicine, such as in closed cycle anesthesia (or low flow inhalation anesthesia), and since 1914, soda lime has begun to be the main choice for carbon dioxide absorbents in recovery breathing and anesthesia. As a carbon dioxide absorbent for clinical medical use, it is required to effectively remove carbon dioxide, and at the same time, it should be inert to anesthetic itself, and not produce toxic reaction, and in order to avoid "choking" of patient due to excessive dust of absorbent, the carbon dioxide absorbent itself needs to have certain strength. In addition, the carbon dioxide absorbent should also have an indication of its effectiveness. The current medical carbon dioxide absorbent comprises calcium hydroxide type, barium hydroxide type and lithium hydroxide type, wherein the calcium hydroxide type absorbent is the medical carbon dioxide absorbent which is most widely applied at present due to good absorption efficiency and low cost, and is also produced by various manufacturers at home. However, the existing domestic products generally have poor intra-particle combination and low hardness, and are easy to generate fine powder due to collision in the transportation and use processes, and the fine powder is very dangerous in clinical anesthesia, and can be inhaled by patients to cause asthma or dyspnea, so the domestic products have low price and are not compared with the imported products in the market. Therefore, it is necessary to develop a calcium hydroxide type carbon dioxide absorbent having high hardness and low dust.

In patent CN1155438C, calcium hydroxide is used as absorbent, and inorganic humectant such as magnesium chloride or calcium chloride and organic humectant such as dihydroxy or polyhydroxy substance are added to maintain moisture in the absorbent. The invention adopts calcium sulfate hemihydrate (gypsum) as a settling agent and is matched with aluminum powder capable of generating hydrogen to improve the crushing strength and the internal bulk of the particles, but the gypsum has low cohesiveness and is difficult to obtain product particles with higher hardness, and the invention does not contain sodium hydroxide or potassium hydroxide, so that the capability of absorbing carbon dioxide is reduced.

The patent CN102258938B discloses a medical carbon dioxide absorbent soda lime and a preparation method thereof, the invention uses calcium hydroxide as a main absorbent, and simultaneously adds a small amount of sodium hydroxide or potassium hydroxide, adopts a disintegrating agent for medicine, such as sodium carboxymethyl starch, cross-linked povidone, low-substituted hydroxypropyl cellulose, microcrystalline cellulose and the like, to improve the porosity inside the product, and the product hardness is realized by the regulation and control of an extrusion device. Since the main function of the disintegrant is to eliminate the binding force of the tablet to disintegrate the tablet, and the extrusion process is also difficult to obtain dense product particles, the method cannot obtain a product with high hardness and is easy to shed powder after long-term storage.

Patent CN104399359A discloses a medical carbon dioxide absorbent and a preparation method thereof, wherein sodium hydroxide, calcium hydroxide, potassium hydroxide and lithium hydroxide are used as absorbents, and a disintegrating agent microcrystalline cellulose is also added, so that the final product is powder ground to 800 meshes. The content of sodium hydroxide and potassium hydroxide in the invention is very high (more than 50 percent), toxic reaction is easy to occur in clinical use, and the powdery product has the danger of choking throat, so the invention is completely not suitable for the medical clinical field.

The patent adopts the disintegrating agent to realize the internal loosening of the product so as to improve the absorption rate of carbon dioxide, but the disintegration property and the low cohesiveness of the disintegrating agent cause the hardness of the product to be not high, and meanwhile, the product is easy to pulverize in the long-term storage process, sodium aluminosilicate and the like are adopted as inorganic binders, and polyvinyl alcohol (PVA) is used as an organic binder to prepare the calcium hydroxide type carbon dioxide absorbent, the sodium aluminosilicate can effectively improve the hardness of the product, the PVA can prevent the pulverization of the product, but because the PVA cannot resist high temperature, the drying temperature of the product cannot exceed 100 ℃, the reaction between the sodium aluminosilicate and the calcium hydroxide is not good enough, and the hardness of the final product is still not high.

Disclosure of Invention

In view of the above, the present invention aims to provide a novel high-strength calcium hydroxide type carbon dioxide absorbent and a preparation method thereof, wherein the obtained absorbent has strong binding capacity of particles, no powder falling during transportation and use, no pulverization phenomenon during long-term storage, and high safety.

The technical scheme of the invention is as follows: 50-100 parts of calcium hydroxide, 0-5 parts of sodium hydroxide, 0-5 parts of potassium hydroxide, 1-5 parts of an inorganic humectant, 1-5 parts of ethylene vinyl acetate copolymer powder, 1-5 parts of an inorganic binder, 0.01-1 part of a pH indicator and 10-20 parts of deionized water; wherein the inorganic binder is sodium aluminosilicate or white cement.

Preferably, 70-80 parts of calcium hydroxide, 0-3 parts of sodium hydroxide, 0-3 parts of potassium hydroxide, 2-3 parts of a humectant, 2-4 parts of an ethylene-vinyl acetate copolymer, 1-5 parts of an inorganic binder, 0.01-1 part of a pH indicator and 10-25 parts of deionized water.

Preferably, the ethylene-vinyl acetate copolymer is powder, the melting point is 90-120 ℃, the melt index is 40-100 g/10min, and the particle size of the powder is more than 50 meshes.

Preferably, the inorganic humectant adopts one of magnesium chloride or calcium chloride; the pH indicator adopts one of methyl violet or Dadan yellow.

Preferably, the inorganic binder is sodium aluminosilicate.

As a general technical scheme, the invention also provides a preparation method of the novel high-strength calcium hydroxide type carbon dioxide absorbent, which comprises the following steps,

(1) pre-mixing part of sodium hydroxide and potassium hydroxide with all other raw materials, and ball-milling for a period of time in a ball mill;

(2) adding a proper amount of deionized water, and pressing into particles, tablets or strips with a preset shape;

(3) drying for a period of time;

(4) preparing the residual sodium hydroxide and potassium hydroxide into an aqueous solution, uniformly spraying the aqueous solution on the surface of a product, and drying for a period of time;

(5) and finally, hydrating to a certain water content to obtain a finished product (10-20 parts of water).

Preferably, the ball milling time in the step (1) is 20-90 min.

Preferably, the step (2) is carried out by pressing to form granules, tablets or strips with a predetermined shape by a die pressing method.

Preferably, the step (3) is dried in an oven at 120-140 ℃ for 5-15 min.

Preferably, the weight ratio of the part of sodium hydroxide to the total weight of sodium hydroxide in the step (1) is 0-0.67: 1, and the weight ratio of the part of potassium hydroxide to the total weight of potassium hydroxide in the step (1) is 0-0.67: 1; and (4) drying for 5-15 min at 120-140 ℃ by using an oven.

Compared with the prior art, the invention has the following beneficial effects:

(1) the ball milling method is adopted in the mixing process, so that the granularity of various raw materials is finer, and the mixing effect is better;

(2) the invention has the characteristics that sodium hydroxide or potassium hydroxide is added in two times or is only added in the later stage drying procedure in the preparation process, one part is firstly mixed with other raw materials, and the rest is sprayed on the surface of the product in the form of aqueous solution, so that the surface of the product has stronger alkalinity; in the invention, sodium aluminosilicate is used as an inorganic adhesive which is generally difficult to react with calcium hydroxide, and the sodium aluminosilicate can react with the calcium hydroxide at a higher temperature to obtain strengthening agent products such as calcium silicate, calcium aluminate, tri-calcium silicate and the like only in a strong alkaline environment after the sodium hydroxide or the potassium hydroxide is added, and the strengthening agents bond the calcium hydroxide together, thereby obtaining high strength; in the invention, sodium hydroxide or potassium hydroxide is concentrated on the surface of a product, so that the surface of the product has strong basicity under the condition of low content of sodium hydroxide or potassium hydroxide, and sodium aluminosilicate is easy to react with surface calcium hydroxide to form a strong and hard surface, so that the product can obtain high surface hardness and avoid the phenomenon of powder falling;

(3) the invention is also characterized in that ethylene vinyl acetate copolymer (EVA) resin powder is also used as an organic adhesive. Although high initial surface hardness can be obtained only by using sodium aluminosilicate as an inorganic binder, calcium hydroxide on the outer layer of product particles can be slightly dissolved after absorbing water along with the prolonging of the standing time, so that the internal acting force is gradually weakened, and the product is finally pulverized; the invention solves the problem by adding EVA resin powder, and the EVA resin powder has small particle size and is easy to disperse in other raw materials. The EVA resin can be used as hot melt adhesive, the high-melt-index EVA resin has very low viscosity after being heated and melted, can fully wet adherends such as calcium hydroxide and the like, has strong and lasting bonding property after being cooled, and has no toxic or harmful effect completely. The EVA resin has good water resistance at normal temperature, the cohesiveness of the EVA resin is basically not reduced after the EVA resin is placed for a long time, the powdering phenomenon after the EVA resin is placed for a long time can be avoided, the EVA resin also has good elasticity and strength, and the bonding structure of the EVA resin is not easy to damage and the powder falling phenomenon is avoided even if the EVA resin is impacted by external force. Moreover, the decomposition temperature of the EVA resin can reach 230 ℃, the EVA resin can endure higher temperature, and the drying temperature of product particles can reach 140 ℃; under the condition of the temperature, the inorganic adhesive sodium aluminosilicate can fully react with calcium hydroxide in a short time to obtain good bonding effect and high surface hardness, and the absorbent particles prepared from the inorganic adhesive sodium aluminosilicate have no pulverization phenomenon during transportation, long-term storage and use;

(4) the carbon dioxide absorbent prepared by the invention can completely meet the requirements of national drug standards, has high hardness, no powder falling phenomenon in the transportation and use processes and high density, and has various indexes superior to those of the current domestic products and expensive imported products.

Detailed Description

The present invention will be further described with reference to the following embodiments.