KR100621356B1 - Method of extracting boric-acid using microwave from borate-ore - Google Patents

Abstract

The present invention relates to a method for producing boric acid using microwaves from borate minerals (including CaO, MgO, Na ₂ O, SiO _2, etc. in addition to the main component B ₂ O ₃₎ , which is a natural mineral resource.

Existing boric acid extraction process has a long environmental pollution and extraction time due to the use of excess sulfuric acid, the corrosion of the reaction vessel is serious, requires a lot of energy, may adversely affect the human body during work. Therefore, in order to make up for the shortcomings of the pyrolysis method, pay attention to the fact that the solvent substance can absorb microwaves in the extraction process, and reduce the problems such as pollution and corrosion by minimizing the extraction time and the amount of sulfuric acid by using microwave. Invented a method that can save energy. When heated by microwave, boric acid can be synthesized even if the decomposition treatment time is shortened to 1/6. Therefore, it is a method that can greatly contribute to environmental conservation by saving energy and reducing the amount of waste water by more than 25%.

Boric acid produced in such a process can be a high value-added product such as B ₄ C, BN through the carbonization or nitriding process, boric acid and boron compounds are additives for improving the water resistance of glass and viscosity control of glass fiber, semiconductor It is used in a wide range of fields such as high quality abrasives, substrates, nuclear power plant reactivity control, detergents and paint additives.

By synthesizing boric acid from borate minerals, which are inexpensive ores, and extracting advanced raw materials using the synthesized boric acid, it is possible to secure stable industrial raw materials, high added value of resources, and import substitution effects.

Description

Method for extracting boric acid using microwave from borate minerals {Method of extracting boric-acid using microwave from borate-ore}

The present invention relates to a method for extracting boric acid using microwaves from borate minerals.

Boric acid referred to in the present invention is a flux of borosilicate glass, heat-resistant glass, frit, glass fiber, pigment, enamel and metal welding due to low melting point, and boric acid as glass or granular boric anhydride. , a lens, display frit, liquid rod monetary system for, and the boric acid carbide or nitride, high value-added boron compound is B ₄ C, BN is a jig for semiconductor source material, ballistic materials, neutron absorbers, lubricants, paint additives, polymer It is used in a wide range of fields such as fillers, cosmetic moisturizers, Al deposition boats, and abrasive raw materials.

Boron compounds used in such a wide industrial field do not exist in the boron state but exist in the natural state such as BN oxide, Ca-B-Si oxide, Ca-B oxide, Mg-B oxide, but impurities Many low-purity glass fibers are used in the manufacture of boric acid by acid treatment, such as sulfuric acid, without using it in its natural state, and boric acid is anhydrous borated again, and then synthesized with high-tech materials such as B ₄ C or BN for lubricity. Manufactured with high value-added materials with excellent heat resistance and mechanical properties. In order to synthesize high value-added boron compounds, in general, inexpensive natural ores such as Colemanite (Ca ₂ B ₆ O11.xH ₂ O), Datolite (Ca ₂ B ₂ SiO ₂ .xH ₂ O), Kurnakovite (Mg ₂ B ₆ O) _{11 · xH 2 O), Szaibelyite} (Mg 2 B 6 O 5 · xH 2 O), Pricetete (Ca 2 B 2 SiO 2 · xH 2 O), Kernite (Na 2 B 4 O 7 · 4H 2 O), Tricalconite (Na ₂ B ₄ O ₇ · 5H ₂ O) is acid treated to produce a boride, which is ammonia gas, nitrogen gas, hydrogen + nitrogen gas, argon gas, ammonium chloride, calcium phosphate oxide, ammonium carbonate, The boron compound is synthesized by passing or adding sodium cyanide (potassium), urea, boron chloride, calcium boride, and the like. When manufacturing boron compound by acid treatment, natural ore mixed with boron with sulfuric acid is generally dissolved. At this time, the amount of sulfuric acid used in the boric acid manufacturing process is high, and more than 35% of the power is used for pollution control devices. It is necessary to reduce the amount of sulfuric acid and reduce the production cost by developing.

Therefore, in the present invention, the process of extracting boric acid by the conventional pyrolysis method has a long dissolution time and excessive wastewater is generated due to the use of a large amount of sulfuric acid in the extraction process. Corrosion is severe and may be harmful to the human body during the process. In the present invention, in order to reduce production costs and develop an environment-friendly process, heating characteristics of the 2.45 대역 microwave band, ie, dipole rearrangement, space charge phenomenon, and ferrimagnetic resonance, can be used to shorten the dissolution time in the dissolution process. Boric acid was extracted by designing a process for minimizing the amount.

By doing so, it was possible to reduce the amount of waste water with energy savings while producing boric acid in a process that uses sulfuric acid at a low temperature and at a short time in a short time using microwave.

As a conventional method for preparing boric acid from natural materials containing Ca-B, Mg-B, Si-B, Na-B-based oxides, pyrolysis is generally used. When sulfuric acid is added and heated at a high temperature for a long time using a heating device to dissolve the boron compound into a solution state, other substances are precipitated and separated and extracted.The amount of sulfuric acid is 1.3 ~ higher than the amount that can be stoichiometrically reacted. Since 1.8 times should be added, the heater should be heated above 95 ℃ and the separation time should be maintained for more than 1 hour. Therefore, a large amount of waste water is generated by the use of sulfuric acid, and the energy consumption by heater heating. ), Corrosion of the container due to a long time reaction, harm to human health due to smell, etc.

Therefore, the present invention is to reduce the amount of sulfuric acid using the microwave in the process for producing boric acid using boron ore as a starting material, and to shorten the reaction time. In order to solve the above problems, an environmentally friendly process must be developed, but in the present invention, a heating method in which the polarity of water is applied to the boric acid extraction, not the heating method by a heater that generally uses the heating method, is used in the heating method using microwaves, that is, in the decomposition reaction When using as a solvent, it was confirmed that the solvent can absorb the microwave, the microwave was selected as the heating source.

Microwaves have frequencies of 900 MHz and 2.45 GHz when used primarily for heating purposes. Due to the nature of the microwave passing depth depending on the frequency, many researchers are doing a lot of research to apply to each field. Microwave irradiation in the extraction and synthesis of materials causes all low molecular weight polar solvents to be heated by frictional forces caused by molecular rotation or rearrangement at a rate corresponding to the frequency of the microwave. Therefore, they can be applied to many chemical reactions using solvents. In the case of organic synthesis, many reports have been made on reactions having excellent reaction rates, yields, and selectivities. In many cases, microwaves have been applied to the synthesis of various inorganic materials. Applying microwaves can make the reaction quick, simple and efficient. The effects of microwaves in chemical reactions can be explained by the absorption of microwaves by materials, and the absorption mechanisms are explained by dipole reorientation, space charge phenomena, ferrimagnetic resonance, and the like. However, the exact action between the microwave and the reactant during the reaction is still somewhat unclear.

In order to solve the above problems, many studies have been conducted, but satisfactory effects could not be obtained.

As described above, the present invention is intended to significantly reduce the use of sulfuric acid, to shorten the reaction time (extraction time), and to lower the reaction temperature (extraction temperature), compared to when boric acid is prepared by conventional pyrolysis using natural ore as a starting material. For that purpose.

The present invention will be described in detail through examples.

Example 1

In the present invention, preferred borate natural ore is _{colemanite (CaB 6 O 11 · H} 2 O), Datolite (Ca 2 B 2 Si 2 O 9 · H 2 O) in order to extract the _{acid, Kurnakovite (Mg 2 B 6 O} 11 · use _{xH 2 O), Szaibelyite (Mg} 2 B 6 O 5 · xH 2 O), Tincalconite (Na 2 B 4 O 7 · 5H 2 O), Kernite (Na 2 B 4 O 7 · 4H 2 O) Table It prepared under the same conditions as 1.

table. 1 Boric Acid Extraction Conditions According to Reaction Time

Sample Extraction temperature (℃) Extraction time (min) Primary Sulfate Addition (real / standard) Secondary Sulfate Addition (real / standard) pH One 95 One 1.3 0.6 7 2 95 3 1.3 0.6 7 3 95 5 1.3 0.6 7 4 95 30 1.3 0.6 7

※ There is no unit because the 1st and 2nd sulfuric acid addition amount is the ratio of real (actual addition amount ㎖) and standard (theoretical amount ㎖).
25 g of borate minerals were pulverized dry and mixed with hotwater at 95 ° C., and sulfuric acid diluted to 25% was added thereto, followed by melting with varying reaction time for each sample under the conditions shown in Table 1 while heating the microwave as a heat source. At this time, the volume ratio of sulfuric acid diluted to 95% hot water and 25% was 10: 1 and the dissolved reactant was filtered with hot water at 95 ℃. Since most of the filtrate passed through the filter during the filtration is a liquid boric acid, the filtrate is put back into the reactor and heated up to the point of breaking, and then ammonium sulfate is added to the heated reaction to prevent solution of calcium compound and precipitation of boric acid. Ammonia water was added for pH adjustment to remove impurities other than insoluble components by precipitation with hydrate. Next, heating was performed to participate in the reaction and remove the remaining ammonia gas. The ammonia gas-free suspension is separated into a precipitate and a filtrate, and filtered. Since most of the filtrate is present in the form of a liquid ammonium borate, a dilute sulfuric acid solution is added to the filtrate in order to separate it into a form of boric acid and ammonium sulfate. Variations were added. The boric acid filtrate was concentrated at 95 ° C. for 1 hour using a vacuum evaporator, and then cooled to room temperature for recrystallization. Filtered to recover the boric acid crystallized from the concentrate by the difference in solubility with temperature, and then dried at 60 ℃ for a certain period of time in the dryer to extract the solid boric acid. As a result, the reaction time was shorter than that of boric acid when extracted by heating for 30 minutes with the existing heat source, but the sample applied with microwave was more crystalline and the purity was higher.

Example 2

Borate mineral as a reaction starting material and the experimental method are the same as in Example 1.

Table 2. Boric Acid Extraction Conditions According to Reaction Temperature and Time

Sample Extraction temperature (℃) Extraction time (min) Primary Sulfate Addition (real / standard) Secondary Sulfate Addition (real / standard) pH 5 75 5 1.3 0.6 7 6 75 30 1.3 0.6 7 7 55 5 1.3 0.6 7 8 55 30 1.3 0.6 7

※ There is no unit because the 1st and 2nd sulfuric acid addition amount is the ratio of real (actual addition amount ㎖) and standard (theory amount ㎖).
As in Example 1, 25 g of borate mineral was dry pulverized, mixed with hot water at 95 ° C., and sulfuric acid diluted to 25% was added to change the extraction temperature to 75 to 55 ° C. while using microwave as a heat source. It melt | dissolved in 30 minutes. Since the process is the same as in Example 1. As a result, when the extraction time was fixed at 30 minutes, boric acid could be obtained in the same manner as when extracted at 55 ° C, but the extraction time was lower than when the extraction time was 5 minutes. Boric acid was extracted.

Example 3

Borate mineral as a reaction starting material and the experimental method are the same as in Example 1.

Table 3. Boric Acid Extraction Conditions According to the Amount of Sulfuric Acid

Sample Extraction temperature (℃) Extraction time (min) Primary Sulfate Addition (real / standard) Secondary Sulfate Addition (real / standard) pH 9 95 5 1.0 0.6 7 10 95 5 0.8 0.6 7 11 95 5 0.2 0.6 7

※ There is no unit because the 1st and 2nd sulfuric acid addition amount is the ratio of real (actual addition amount ㎖) and standard (theory amount ㎖).
As in Example 1, 25 g of borate mineral was dry pulverized, mixed with hot water at 95 ° C., and sulfuric acid diluted to 25% was added to the microwave as a heat source, and the extraction temperature was fixed at 95 ° C. and the extraction time was set to 5 minutes. The experiment was carried out by varying the amount of sulfuric acid added.

As a result, when microwave was used as the heat source during boric acid extraction, boric acid was extracted and the yield and crystallinity were better, as in the case of using the amount of sulfuric acid, even though the amount of sulfuric acid was reduced.

The present invention relates to a manufacturing method for extracting boric acid from various natural minerals, including boron as a utilization process of natural mineral resources. Extraction by conventional pyrolysis method has a long dissolution time and corrosion of the reaction vessel and excess waste water due to acid used in the extraction process. In order to make up for these drawbacks, the process of reducing the amount of acid by up to 40% while reducing the extraction time from 30 minutes to 5 minutes and reducing the extraction temperature from 30 minutes to 5 minutes by introducing microwaves in the melting process. Was established.

Claims (2)

A method of producing boric acid in which a borate natural ore is mixed with a hot water at 95 ° C. and a sulfuric acid solution diluted to 25% in a reaction vessel, and then the reaction vessel is placed in a microwave oven and irradiated with microwaves to extract boric acid. The method of claim 1, From borate mineral 25g of borate natural ore, the volume ratio of hotwater at 95 ℃ and sulfuric acid solution diluted to 25% is 10: 1 and the extraction temperature of microwave is 55-95 ℃ and extraction time is 1-30 minutes. Method for extracting boric acid.