CN1294083C - Functional calcium oxide and mfg. process and application thereof - Google Patents

Abstract

The invention discloses a method for producing functional calcium oxide, which uses high-content natural calcium as a raw material, carries out plastic processing for the first time at high temperature, crushes and sieves, produces slaked lime solution, and undergoes slaking and filtering After drying, carry out the second plastic processing, crush and sieve again, the present invention is the functional calcium oxide obtained after two plastic processing at 1000°C-1400°C, which is different from quicklime products produced by common processes There is a big difference, its chromaticity is higher than 95%, and it does not generate heat when it is wet, so it has higher stability than the traditional calcium oxide in the past, and its deodorization, anti-bacteria and other aspects have been significantly improved. It can be widely used as an additive in the manufacture of functional calcium oxide-containing foods and packaging materials for functional calcium oxide-containing foods.

Description

A kind of manufacture method of functional calcium oxide

technical field

The invention relates to the production technology of calcium oxide, in particular to a production method of functional calcium oxide.

Background technique

The calcium oxide products manufactured by the usual process generally complete the plasticity at 500°C-1000°C, and the white chroma of the obtained plastic quicklime (CaO) is lower than 92%, and it is quickly converted into Ca(OH) ₂ when wet, and at the same time Rapid heating, volume expansion, and poor stability require harsh storage conditions and are difficult to store for a long time.

Contents of the invention

The purpose of the present invention is to provide a method for producing functional calcium oxide that has high chroma, does not generate heat when wet, has good stability, and has obvious improvements in deodorization and antibacterial (bacteriostatic) properties.

The present invention is achieved through the following technical solutions:

A method for producing functional calcium oxide, the process steps are as follows:

a. Select a material with a high content of natural calcium as a raw material, heat the raw material at a temperature of 1000-1400°C for 2-6 hours, and perform the first plastic processing;

b. Crushing and sieving;

c. Take the plastic calcium oxide powder prepared above, add water and inorganic acid to produce a slaked lime solution, and stir the slaked lime solution after acidity adjustment at a temperature of 50-100°C for 6-10 hours to mature, and then filter , and the filtrate was dried at 100° C. for 4 hours;

d, the dry plastic obtained above is carried out the second plastic processing using the same process conditions as step (a);

e. Crushing and sieving again to obtain functional calcium oxide.

In the above step (a), it is best to heat at 1100° C. for 4 hours under normal plastic temperature and heating time.

In the above (c) step, the inorganic acid used in the present invention can be hydrochloric acid, nitric acid, sulfuric acid or phosphoric acid, etc., and there is no specific limitation and requirement on this. The purpose of adding mineral acid is to adjust the acidity and stabilize the mature powder. The adjusted acidity of the slaked lime solution is preferably about PH=7-8.

In order to improve the unique functions that the functional calcium oxide of the present invention has, such as: deodorization, anti-bacteria function, in the (c) step, that is, in the ripening process of the slaked lime solution, it can be pressed according to different purposes by 0.1 -3% by weight adding a variety of functional metal substances such as metal salts such as Pt, Ag, Cu, Mn, Zn, etc., the functional calcium oxide containing functional metal salts can be improved in deodorization and anti-bacteria Improve and strengthen.

The present invention is the functional calcium oxide obtained after plastic processing twice at 1000°C-1400°C, which is very different from the quicklime products produced by the usual process. Its chroma is higher than 95%, and it does not generate heat when wet. Therefore, it has higher stability than the traditional calcium oxide in the past, and its deodorization, anti-bacteria and other aspects have been significantly improved and improved, and can be widely used as an additive to manufacture foods containing functional calcium oxide and functional calcium oxide. Calcium oxide food packaging material.

The present invention will be explained in detail below through examples and comparative experiment examples.

Example 1

In principle, as long as it contains natural calcium, it can be used as the raw material of the present invention, so there is no strict restriction on the raw material, but considering that the main application of the present invention is in the food field, the shell of marine shellfish can be used as the raw material in the present invention, for example Shells of clams, scallops, oysters, etc., or starfish, fish bones, etc. are used as raw materials.

Get 1000g scallop shells and rinse with tap water until clean, then dry. The dried shell is put into an incinerator at 1100°C and burned for 4 hours for the first plastic processing. After completing the first plasticity, the obtained plastic calcium oxide is pulverized by a ball mill, sieved with a 200-mesh sieve, then a certain amount of water and inorganic phosphoric acid are added to produce a slaked lime solution, and the acidity of the slaked lime solution is adjusted to PH= 7-8. The slaked lime solution was aged at 100° C. for 6 hours after being stirred at 60° C. for 4 hours. After the slaking is completed, the slaking liquid is filtered with a pressure membrane filter to remove impurities, and the obtained pure slaked lime filtrate is dried at 100° C. for 4 hours. Then the dried product was reheated at 1100°C for 4 hours for the second plastic processing. After natural drying, it was pulverized and passed through a 200-mesh sieve to obtain the final functional calcium oxide.

The crystallization stability of the quicklime prepared by the traditional method is compared with that of the functional calcium oxide prepared in the above-mentioned embodiments of the present invention, and the indexes adopt the general standard in the industry. The results are shown in Table 1:

Table 1: Comparison of crystallization stability of quicklime and functional calcium oxide distinguish General quicklime Functional calcium oxide of the present invention Remark Whiteness (%) 82 96 CaO content (%) 60 95 100g calcium oxide/1L water Heating temperature (℃) 60 40

The standard for testing the quality of calcium oxide is generally whiteness and CaO content. As can be seen from the results in Table 1, the functional calcium oxide of the present invention exhibits much higher whiteness and CaO content than the control group, thus confirming its better quality. The criterion for verifying the crystallization stability of calcium oxide is the exothermic temperature when it reacts with water. The functional calcium oxide of the present invention has a lower exothermic temperature than the control group, which proves that the reactivity with water is lower than that of the control group. It is proved that the functional calcium oxide of the present invention has satisfactory quality and very stable crystallization.

Example 2

Take 1000g fish bones, wash them, dry them, put them into an incinerator at 1200°C and incinerate them for 5 hours to carry out the first plastic processing. After the first plasticity is completed, the obtained plastic calcium oxide is crushed, sieved with a 200-mesh sieve, and then a certain amount of water and sulfuric acid are added to produce a slaked lime solution, and the acidity of the slaked lime solution is adjusted to PH=7-8. Add 10g of silver salt (accounting for 1% by weight of the raw material) to the slaked lime solution, stir at 70°C for 3 hours and then age at 100°C for 6 hours. After the slaking is completed, the slaking liquid is filtered to remove impurities, and the obtained pure slaked lime filtrate is dried at 100° C. for 4 hours. Then the dried product was reheated at 1200°C for 5 hours for the second plastic processing. After natural drying, it was pulverized and passed through a 200-mesh sieve to obtain functional calcium oxide containing silver salt.

The deodorization and anti-bacteria functions of the present invention will be further explained through the experimental examples below.

Experimental example 1

In order to check the deodorization and anti-bacteria function of the functional calcium oxide of the present invention, the antibacterial properties of E. coli and the deodorization function of ammonia by using the functional oxide obtained in the above-mentioned embodiment 1 and plastic quicklime at a general temperature A comparative experiment was carried out.

The antibacterial ability of Escherichia coli is based on a widely used common method, that is, after the functional calcium oxide sample of the present invention is used for treatment, the number of viable bacteria is detected after 24 hours of cultivation. (shake flask culture method (shake flask), the method is to inoculate a certain amount of diluted Escherichia coli bacterial liquid in phosphate buffer solution, after shaking culture for a certain period of time, detect the method for the number of viable bacteria before and after the culture).

The detection of the deodorization function is completed by measuring the concentration of residual ammonia gas after the samples are treated for 60 minutes. Specifically, a certain amount of ammonia gas is treated with a certain amount of functional calcium oxide sample for a certain period of time, and then the concentration difference of ammonia gas before and after treatment is measured.

The results of the two experiments are shown in Table 2

Table 2: Comparison of antibacterial (inhibitory) performance and odor removal function between quicklime and functional calcium oxide distinguish Antibacterial ability (Escherichia coli number, cfu/ml) Odor removal rate (concentration, ppm) start 24 hours later start 60 minutes later quicklime 4.7×10 ⁴ 2.5×10 ⁵ 500 400 Functional Calcium Oxide 4.7×10 ⁴ 100 500 295

From the results in Table 2, it can be seen that the Escherichia coli treated with quicklime did not change much after 24 hours, while the Escherichia coli treated with functional calcium oxide was basically killed after 24 hours. For the deodorization effect, the concentration of ammonia gas treated with quicklime did not change much before and after treatment, but the concentration of ammonia gas treated with functional calcium oxide decreased significantly after treatment. Thus it is confirmed that the functional calcium oxide has a high antibacterial (inhibition) effect and a strong deodorization function.

Experimental example 2

In order to check the antibacterial (inhibition) performance and the deodorization function of the silver-salt functional calcium oxide obtained according to embodiment 2, the sample obtained in embodiment 2 and the quicklime obtained by the traditional method were used to complete the same as above-mentioned experimental example 1. A comparative experiment was carried out with the same inspection method. The results are shown in Table 3.

Table 3: Comparison of antibacterial (inhibitory) performance and deodorization function between quicklime and functional calcium oxide containing silver salt distinguish Antibacterial ability (Escherichia coli number, cfu/ml) Odor removal rate (concentration, ppm) start 24 hours later start 60 minutes later quicklime 4.7×10 ⁴ 2.5×10 ⁵ 500 420 Functional Calcium Oxide Containing Silver Salt 4.7×10 ⁴ 0 500 160

It can be seen from Table 3 that the experimental group treated with quicklime had no change in the number of bacteria after 24 hours of cultivation, while the experimental group treated with the silver salt-containing functional calcium oxide of the present invention did not detect Escherichia coli after 24 hours of cultivation. In the deodorization test, the ammonia concentration of the experimental group treated with quicklime remained unchanged after 60 minutes, while the ammonia concentration of the experimental group treated with the silver salt-containing functional calcium oxide of the present invention decreased significantly after 60 minutes of treatment. At the same time, it is not difficult to see from the comparative data of Experimental Example 1 that the functional calcium oxide added with metal silver ions is much superior in antibacterial (inhibition) and deodorizing properties than the functional calcium oxide without added metal ions.

Because the present invention has good deodorizing and antibacterial (inhibiting) functions, the functional calcium oxide of the present invention can be widely used as an additive in the manufacture of functional calcium oxide-containing foods and packaging materials for functional calcium oxide-containing foods.

The following is a detailed description through the anti-bacteria (inhibition) test example.

(1) Antibacterial (inhibitory) test of foods containing functional calcium oxide:

Experiment 3: Cucumber

In order to investigate the antibacterial (inhibition) properties of foods containing functional calcium oxide, take vegetables—cucumbers, wash them with tap water, cut them into 2mm thick slices, and treat them with 200ppm sodium hypochlorite. Then, use the solution prepared by the silver salt functional calcium oxide of Example 2, 200ppm sodium hypochlorite, and tap water to soak for 10 minutes and 30 minutes respectively, and observe and measure the number of general bacteria, Escherichia coli after 24 hours and 48 hours at 10°C. number. The results are shown in Table 4:

Table 4: Antibacterial (inhibitory) test of foods containing functional calcium oxide (cucumber) Soaking time (minutes) pH (cfu/ml) Immediately after soaking 10°C, after 24 hours 10℃, after 48 hours General bacteria Escherichia coli General bacteria Escherichia coli General bacteria Escherichia coli After 200ppm sodium hypochlorite treatment, 0.5% (weight) functional calcium oxide suspension 15 9.57 300 -- 300 -- 300 -- 30 10.70 300 -- 300 -- 300 -- Soak in tap water 15 6.03 6.7×10 ³ 65.0×10 ¹ 5.0×10 ⁴ 4.4×10 ² 6.4×10 ⁵ 1.1×10 ³ 30 6.02 6.9×10 ³ 4.0×10 ¹ 6.9×10 ⁴ 5.1×10 ² 7.0×10 ⁵ 2.8×10 ⁴ Soak in 200ppm sodium hypochlorite 15 6.18 6.7×10 ³ -- 2.4×10 ³ -- 6.4×10 ³ -- 30 6.18 4.9×10 ³ -- 5.4×10 ³ -- 6.3×10 ⁴ --

From Table 4, it can be seen that the experimental results of the sample of Example 2 of the present invention have a high antibacterial ability no matter whether it is after 24 hours or after 48 hours after soaking for 15 minutes or 30 minutes, which is far higher than that of the matched group. many.

Experimental example 4: seafood - squid

Soak the freshly thawed squid in the suspension prepared by the silver salt-containing functional calcium oxide prepared in Example 2 for 60 minutes, and use tap water as a control group, and observe the results according to the method in Table 5.

Table 5: Antibacterial (inhibitory) test of foods containing functional calcium oxide (squid) soaking method Soaking time (minutes) The number of viable bacteria (cfu/ml) soak immediately 10°C, after 24 hours 10℃, after 48 hours General bacteria coliform bacteria General bacteria coliform bacteria General bacteria coliform bacteria 0.5% functional calcium oxide suspension 60 300 --- 300 --- 300 --- tap water 60 3.4×10 ⁴ 5.1×10 ⁴ 4.2×10 ⁴ 3.0×10 ⁴ 8.0×10 ⁶ 7.0×10 ⁴

From Table 5, it can be seen that the experimental results of the sample of Example 2 of the present invention have high antibacterial (bacteriostatic) ability no matter after soaking for 24 hours or after 48 hours, which is much higher than that of the control group.

The above research shows that the addition of functional calcium oxide can remove peculiar smells such as fishy smell and improve the antibacterial (antibacterial) performance of food, thus prolonging the storage time of food and improving the quality of food. Such foods may include various foods such as vegetables, seafood, noodles, sauces, pickles, bread, biscuits, and fast food. Its addition amount can account for 0.5-3% of raw material weight.

(2) Antibacterial (antibacterial) performance test of food packaging materials containing functional calcium oxide

Experimental example 5:

In order to check the antibacterial properties of the food packaging material containing functional calcium oxide, the mixture of polyethylene and the functional calcium oxide of Example 1 prepared earlier than the required concentration is mixed to produce the original batch (master batch), and then added to the polyethylene The original batch is 10-30%, so that the concentration of functional calcium oxide reaches 1-3%, and the film is manufactured, and the detection method adopts the current film sticking method. The specific method is to inoculate Escherichia coil (Escherichia coil, JCM3972) and Staphylococcus aureus (Staphylococcus aureus, IF012732) on the film for cultivation, and finally extract the culture solution, and then detect the number of viable bacteria in the extract solution. The control group used polyethylene film without adding functional calcium oxide, and the method was exactly the same as that of the experimental group. The results are shown in Table 6.

Table 6: Antibacterial performance investigation of food packaging materials containing functional calcium oxide (polyethylene PE) experimental project Experimental material Initial bacterial count (cfu/ml) After 24 hours (cfu/ml) Reduction rate (%) coliform bacteria unprocessed 2.42×10 ⁵ 1.57×10 ⁶ --- Add 1% (weight) 2.42×10 ⁵ 300 99.99 Add 3% (weight) 2.42×10 ⁵ --- 100.0 Staphylococcus aureus unprocessed 2.45×10 ⁵ 1.25×10 ⁵ -- Add 1% (weight) 2.42×10 ⁵ 300 99.7 Add 3% (weight 2.42×10 ⁵ --- 100.0

^** Reduction rate (%)=(number of bacteria in the control group-number of bacteria in the experimental group)/number of bacteria in the control group×100

As can be seen from Table 6, the experimental group has a very high anti-bacteria (inhibition) function, and it improves with the increase of the added amount. The control group had no antibacterial effect. It proves that adding functional calcium oxide to food packaging raw materials can become a good food packaging material with good antibacterial (antibacterial) effect.

Experimental example 6:

In order to test the antibacterial ability of the packaging material after coating film treatment on the surface of the packaging material, the following experiments were carried out. Coat 0.4g/ ^m2 the silver salt-containing functional calcium oxide of embodiment 2 on the polyethylene bag surface, the control group has adopted pure polyethylene bag. The experimental method and detection method are the same as in Experimental Example 5. The results are shown in Table 7:

Table 7: Antibacterial ability (polyethylene) of packaging materials after coating film treatment on the surface of packaging materials experimental project Experimental material Initial bacterial count (cfu/ml) After 24 hours (cfu/ml) Reduction rate (%) coliform bacteria unprocessed 4.8×10 ⁵ 2.1×10 ⁷ Coating treatment 4.8×10 ⁵ 10 99.9 Staphylococcus aureus unprocessed 8.6×10 ⁵ 1.4×10 ⁵ Coating treatment 8.6×105 10 99.9

It can be seen from Table 7 that the polyethylene packaging material coated with functional calcium oxide has a very high antibacterial (antibacterial) function. The pure polyethylene packaging material in the control group has no antibacterial properties. Polyethylene coated with functional calcium oxide can become a packaging material with excellent antibacterial function.

Experimental example 7:

In order to test the antibacterial (inhibition) property of artificial rubber (urethane) food packaging materials containing functional calcium oxide, 1%-3% (weight) of functional calcium oxide is added when making elastic artificial rubber by foam molding. raw material. The same method as in Experimental Example 6 was used to detect its antibacterial (antibacterial) function, and the control group used unadded raw materials. The results are shown in Table 8:

Table 8: Antimicrobial properties of elastic elastomer food packaging materials containing functional calcium oxide experimental project Experimental material Initial bacterial count (cfu/ml) After 24 hours (cfu/ml) Reduction rate (%) coliform bacteria unprocessed 1.4×10 ⁶ 1.57×10 ⁶ --- Add 1% (weight) 1.4×l0 ⁶ 30 99.5 Add 3% (weight 1.4×10 ⁶ -- 99.5 Staphylococcus aureus unprocessed 3.7×10 ⁵ 4.3×10 ³ -- Add 1% (weight) 3.7×10 ⁵ 30 99.3 Add 3% (weight 3.7×10 ⁵ --- 99.3

It can be seen from Table 8 that the elastic artificial rubber food packaging material containing functional calcium oxide has excellent antibacterial (antibacterial) function.

To prepare food packaging materials containing functional calcium oxide, the functional calcium oxide of the present invention can be added to the raw materials of the packaging material at a weight ratio of 0.5-3%, or coated with 0.4g-1.0g/m2 on the surface of the packaging material ² functional calcium oxide. As a material for food packaging, functional calcium oxide can not only be used for various polymer materials, but also can be used as an additive raw material for materials such as ceramics. The use of this packaging material can remove strange and peculiar smells such as fishy smell, prolong the storage time of food, and increase the value of commodities.

In summary, the functional calcium oxide manufactured according to the present invention has a stable crystalline state, which is convenient for storage and transportation. Improving the ability of anti-bacteria and deodorization is promising as an additive for food and food packaging materials. At the same time, because the shells of shellfish that are currently polluting the coastal environment can be used as raw materials, the method has high economic value and great social significance in terms of resource reuse and environmental protection.

Claims (3)

1, a kind of manufacture method of functional calcium oxide, its processing step is in regular turn:

A, the material of choosing the high-content natural calcium are raw material, and raw material was heated 2-6 hour under 1000-1400 ℃ temperature, carry out the plastic working first time;

B, pulverize, sieve;

C, get the above-mentioned plasticity lime powder that makes, add entry and mineral acid, make the slaking lime solution, stir under 50-100 ℃ of temperature through the slaking lime solution after the acidity adjustment and made its maturation in 6-10 hour, filter then, filtrate is following dry 4 hours at 100 ℃;

In the above-mentioned steps, the acidity of the slaking lime solution after acidity adjustment is PH=7-8;

In the above-mentioned steps, mineral acid is any one in hydrochloric acid, nitric acid, sulfuric acid or the phosphoric acid;

D, the above-mentioned dry plasticity thing that obtains adopted with (a) identical processing condition of step carry out the plastic working second time;

E, pulverize once more, sieve, obtain functional calcium oxide.

2, the manufacture method of a kind of functional calcium oxide according to claim 1 is characterized in that: in described (a) step, raw material was heated 4 hours under 1100 ℃ temperature, carry out the plastic working first time.

3, the manufacture method of a kind of functional calcium oxide according to claim 1, it is characterized in that: in described (c) step, press the 0.1-3% weight ratio and add metal-salt in slaking lime solution maturation process, metal-salt is any one in the metal-salt of Pt, Ag, Cu, Mn or Zn.