CN102502907A - Production method of attapulgite loaded hydroxyapatite composite defluorination filter bulb - Google Patents

Abstract

The invention discloses a production method of an attapulgite loaded hydroxyapatite composite defluorination filter bulb, which comprises the following steps: preparing attapulgite loaded hydroxyapatite powder from industrial-grade calcium hydroxide, phosphoric acid, acetic acid and attapulgite as raw materials, regulating the solubility of calcium hydroxide using acetic acid, and controlling calcium-phosphorus ratio and pH value of the solution so as to ensure the purity and the defluorination capacity of the products; and fabricating the attapulgite loaded hydroxyapatite powder into pellets of diameters 0.5-1.5mm, and drying and molding the pellets at a temperature ranging from 350 to 450 DEG C so as to obtain attapulgite loaded hydroxyapatite composite defluorination filter bulb. The composition of attapulgite and hydroxyapatite reduces cost, is helpful for pellet formation, and enhances defluorination of hydroxyapatite. The method of the invention uses cheap and easily-accessible raw materials, high capacity of defluorination filter bulbs, long service life and small fluent water resistance, , and is simple in preparation, easy for control and regeneration, and easy for large-scale industrial production and promotion.

Description

Production method of attapulgite-loaded hydroxyapatite composite defluoridation filter ball

technical field

The invention relates to a production method of a composite defluoridation filter ball, in particular to a production method of an attapulgite-loaded hydroxyapatite composite defluorination filter ball suitable for removing excessive fluorine in drinking water.

Background technique

Fluorine is one of the most widely distributed elements on the earth's surface. It is generally believed that trace amounts of fluorine are beneficial to the firmness of bones, but excessive fluorine is toxic to the human body. Since the human body absorbs as much as 90% of fluorine in drinking water, the fluorine in the body mainly comes from drinking water. Fluorosis caused by drinking high-fluoride water is an endemic disease worldwide. In mild cases, it can cause dental fluorosis, and in severe cases, it can cause skeletal fluorosis. The World Health Organization stipulates that the fluorine content in drinking water should not exceed 1.5mg/L. Since high-fluorine water is mainly distributed in rural areas and pastoral areas with harsh environments, complex terrain, lack of water and electricity, inconvenient transportation, backward economy, and low income, although the technology of defluoridation of drinking water has developed rapidly, the adsorption method is still the current domestic method. The most commonly used method of defluoridation of drinking water. There are many kinds of fluoride removal adsorbents, such as zeolite, clay, activated carbon, activated alumina and bone carbon, etc., but considering the difficulty, cost and fluoride removal capacity of the regeneration method, many adsorbents have not been practically applied.

Attapulgite is a hydrous magnesium aluminum silicate sodium crystal mineral, which has certain adsorption properties due to its unique crystal structure, but the single use of attapulgite as an adsorbent has certain limitations in its adsorption performance and adsorption effect . As a functional material for drinking water treatment, hydroxyapatite has good ion exchange and adsorption properties, and is safe and has no toxic side effects. It can not only remove excess fluorine in drinking water, but also remove other harmful elements in water. At present, in the research of hydroxyapatite defluoridation agent, the research on hydroxyapatite powder is relatively more. For example, the invention patent No. 200610029366.7 discloses an improved preparation method of hydroxyapatite powder. The hydroxyapatite powder is easy to harden during the defluoridation process, and the water flow resistance is large, which is not conducive to the regeneration of the defluoridation agent. Invention Patent No. 201010264616.1 discloses a production method for drinking water defluoridation filter material. This defluoridation filter material is porous spherical hydroxyapatite, which has the advantages of high fluoride removal capacity, easy regeneration, and smooth water outlet. Among them, the hydroxyapatite powder is synthesized by using cheap raw materials and precipitation method, the production process is simple and easy to control, and the equipment investment is low, which is beneficial to large-scale industrial production and popularization and application. However, the control of calcium-phosphorus ratio and pH value in this production method is the key to the production of pure hydroxyapatite. If the control is not good, the product is likely to be mixed with by-products such as calcium hydrogen phosphate, calcium dihydrogen phosphate, and calcium phosphate, which will affect the product. fluoride removal capacity.

Contents of the invention

Technical problem: The purpose of the present invention is to overcome the deficiencies in the prior art and provide a fluoride removal filter ball with attapulgite loaded hydroxyapatite with simple preparation process, easy control, high capacity and high purity. production method.

Technical solution: The production method of the attapulgite-loaded hydroxyapatite composite defluoridation filter ball of the present invention:

a. Preparation of attapulgite-loaded hydroxyapatite powder:

(1) Using industrial grade calcium hydroxide, phosphoric acid, acetic acid and attapulgite as raw materials;

(2) Add water with 50% of the capacity of the reactor into the reactor, and raise the temperature to 75-80°C;

(3) Add a certain amount of acetic acid into the reaction kettle, stir evenly, the mass percentage of a certain amount of acetic acid and water is 0.2-0.4%;

(4) Weigh calcium hydroxide accounting for 25% of the water quality, add it to the reaction kettle, and stir for 3 to 5 minutes;

(5) Weigh phosphoric acid with a mass of 80-88% calcium hydroxide, add phosphoric acid to water three times the volume of phosphoric acid to make a phosphoric acid solution;

(6) Add the phosphoric acid solution dropwise into the reactor at a rate of 10-15kg/min;

(7) React at a temperature of 75-80°C for 2.5 hours;

(8) Add attapulgite with 50-60% calcium hydroxide mass, stir evenly, and react at a temperature of 75-80°C for 1 hour;

(9) Take out the product, dehydrate, wash, dry, and pulverize to obtain attapulgite-loaded hydroxyapatite powder;

b. Preparation of attapulgite loaded hydroxyapatite defluoridation filter ball:

(1) Put the attapulgite-loaded hydroxyapatite powder into the ball forming machine, spray the sodium carboxymethylcellulose or hydroxyethyl cellulose binder with a mass percentage of 1-1.5%, and make the powder into small balls with a diameter of 0.5-1.5mm;

(2) Take out the pellets, dry them at 350-450°C, and then obtain attapulgite-loaded hydroxyapatite composite defluoridation filter balls with a diameter of 0.5-1.5 mm.

Beneficial effects: the present invention uses cheap calcium hydroxide, phosphoric acid, acetic acid and attapulgite as raw materials to synthesize attapulgite-loaded hydroxyapatite balls, wherein the acetic acid can regulate the solubility of calcium hydroxide and control the ratio of calcium to phosphorus in the solution and pH value to ensure product purity and fluoride removal capacity; the combination of attapulgite and hydroxyapatite reduces the cost, facilitates ball formation, and at the same time plays a synergistic effect on hydroxyapatite defluoridation. The invention has the advantages of cheap and easy-to-obtain raw materials, simple preparation process, easy control, high capacity of fluorine-removing filter balls, easy regeneration, long service life, low water flow resistance, and easy large-scale industrial production and popularization and application. It mainly has the following advantages:

1. The product has a high fluoride removal capacity. Compared with the existing technology, the product has a 25% increase in the fluoride removal capacity;

2. The yield and purity of the product are high, which reduces the total cost of the product;

3. The production process is simple and easy to control, which is conducive to large-scale production and popularization and utilization. the

Detailed ways

Taking a one-ton reactor as an example, the content of industrial grade calcium hydroxide is 92%, the content of phosphoric acid is 85%, and the content of acetic acid is 100%.

Example 1:

1. Add 500L water to the reactor and heat to 75°C;

2. Add 1.5 kg of glacial acetic acid and stir evenly;

3. Weigh 125Kg of calcium hydroxide, add it to the reaction kettle, and stir for 4 minutes;

4. Add 105kg of phosphoric acid into 315kg of water and stir evenly to form a solution;

5. Add the above-mentioned phosphoric acid solution dropwise into the reactor, and control the dropping rate to be 12kg/min;

6. React at a temperature of 75°C for 2.5 hours;

7. Add 70kg attapulgite, stir evenly, and react for 1 hour at a temperature of 75°C;

8. Take out the product, perform dehydration, washing, drying, and crushing to obtain attapulgite-loaded hydroxyapatite powder;

9. Put the attapulgite-loaded hydroxyapatite powder into the ball forming machine, spray the sodium carboxymethyl cellulose binder with a mass percentage of 1%, and make the powder into small balls with a diameter of 0.5-1.5 mm. ball;

10. Take out the pellets, dry and shape them at 400° C. to obtain attapulgite-loaded hydroxyapatite composite defluoridation filter balls with a diameter of 0.5-1.5 mm.

Example 2:

1. Add 500L water to the reactor and heat to 75°C;

2. Add 2kg of glacial acetic acid and stir evenly;

3. Weigh 125Kg of calcium hydroxide, add it to the reaction kettle, and stir for 5 minutes;

4. Add 100kg of phosphoric acid into 300kg of water and stir evenly to form a solution;

5. Add the above-mentioned phosphoric acid solution dropwise into the reactor, and control the dropping rate to be 10kg/min;

6. React at a temperature of 75°C for 2.5 hours;

7. Add 63kg attapulgite, stir evenly, and react for 1 hour at a temperature of 75°C;

8. Take out the product, perform dehydration, washing, drying, and crushing to obtain attapulgite-loaded hydroxyapatite powder;

9. Put the attapulgite-loaded hydroxyapatite powder into the ball forming machine, spray the hydroxyethyl cellulose binder with a mass percentage of 1%, and make the powder into small balls with a diameter of 0.5-1.5mm ;

10. Take out the pellets, dry and shape them at 350° C. to obtain attapulgite-loaded hydroxyapatite composite defluoridation filter balls with a diameter of 0.5-1.5 mm.

Example 3:

1. Add 500L water into the reactor and heat to 80°C;

2. Add 1kg of glacial acetic acid and stir evenly;

3. Weigh 125Kg of calcium hydroxide, add it to the reaction kettle, and stir for 3 minutes;

4. Add 110kg of phosphoric acid into 330kg of water and stir evenly to form a solution;

5. Add the above-mentioned phosphoric acid solution dropwise into the reactor, and control the dropping rate to be 15kg/min;

6. React for 2.5 hours at 80°C;

7. Add 75kg attapulgite, stir evenly, and react for 1 hour at a temperature of 80°C;

8. Take out the product, perform dehydration, washing, drying, and crushing to obtain attapulgite-loaded hydroxyapatite powder;

9. Put the attapulgite-loaded hydroxyapatite powder into the ball forming machine, spray the sodium carboxymethyl cellulose binder with a mass percentage of 1.5%, and make the powder into small balls with a diameter of 0.5-1.5 mm. ball;

10. Take out the pellets, dry and shape them at 450° C. to obtain attapulgite-loaded hydroxyapatite composite defluoridation filter balls with a diameter of 0.5-1.5 mm. the

Claims (1)

1. The production method of the attapulgite-loaded hydroxyapatite composite defluoridation filter ball is characterized in that it comprises the following steps: a. Preparation of attapulgite-loaded hydroxyapatite powder: (1) Using industrial grade calcium hydroxide, phosphoric acid, acetic acid and attapulgite as raw materials; (2) Add water with 50% of the capacity of the reactor into the reactor, and raise the temperature to 75-80°C; (3) Add a certain amount of acetic acid into the reaction kettle, stir evenly, the mass percentage of a certain amount of acetic acid and water is 0.2-0.4%; (4) Weigh calcium hydroxide accounting for 25% of the water quality, add it to the reaction kettle, and stir for 3 to 5 minutes; (5) Weigh phosphoric acid with a mass of 80-88% calcium hydroxide, add phosphoric acid to water three times the volume of phosphoric acid to make a phosphoric acid solution; (6) Add the phosphoric acid solution dropwise into the reactor at a rate of 10-15kg/min; (7) React at a temperature of 75-80°C for 2.5 hours; (8) Add attapulgite with 50-60% calcium hydroxide mass, stir evenly, and react at a temperature of 75-80°C for 1 hour; (9) Take out the product, dehydrate, wash, dry, and pulverize to obtain attapulgite-loaded hydroxyapatite powder; b. Preparation of attapulgite loaded hydroxyapatite defluoridation filter ball: (1) Put the attapulgite-loaded hydroxyapatite powder into the ball forming machine, spray the sodium carboxymethylcellulose or hydroxyethyl cellulose binder with a mass percentage of 1-1.5%, and make the powder into small balls with a diameter of 0.5-1.5mm; (2) Take out the pellets, dry them at 350-450°C, and then obtain attapulgite-loaded hydroxyapatite composite defluoridation filter balls with a diameter of 0.5-1.5 mm.