JP6608293B2 - Degreasing agent for oils and fats - Google Patents

Description

  The present invention relates to a bleaching agent for fats and oils, and in particular, rice oil and physically refined palm oil (RBD palm oil), and most preferably, bleaching of fats and oils applied to a bleaching process for RBD palm oil. It relates to the agent.

  Oils and fats collected from animals and plants (hereinafter sometimes referred to as “crude oil”) are generally degumming treatment to remove phospholipids, deoxidation treatment to remove free fatty acids, water washing treatment to remove soap, pigment It passes through the decoloring process which removes odor, and finally passes through the deodorizing process which removes an odorous component, and is used for uses, such as cooking oil.

As the decolorizing agent used above, for example, an activated clay activated by increasing the specific surface area by acid treatment of dioctahedral smectite clay mineral (also called fuller's earth or bleaching earth) is known (patent). Reference 1).
Moreover, although it does not have the decoloring performance like activated clay, the silica magnesia formulation which the present applicant proposed also has the decoloring performance with respect to fats and oils (refer patent document 2).

  By the way, in the refining of the fats and oils as described above, the final deodorization treatment is performed by steam distillation under heating at 200 to 250 ° C., and it is desired to perform this deodorization treatment at a lower temperature and in a shorter time. . When deodorizing treatment is performed for a long time, the content of harmful substances such as trans fatty acids and 3MCPD (3-monochloropropanediol) increases, and the active ingredients in fats and oils such as tocophenol and sterol tend to decrease. Because there is. In order to perform the deodorizing process at a low temperature and in a short time, it is known that the acid value of the decolorized oil subjected to the decoloring process may be lowered.

On the other hand, recently, fats and oils purified by physical refining treatment (physical refining treatment) have been sold. The physical refining treatment is to deodorize (physical deacidification) treatment after the crude oil is degummed and decolorized. That is, alkali treatment is not performed, and free fatty acids are removed together with deodorization by deodorization by distillation. Since an alkali such as sodium hydroxide is not used, there is an advantage that purification treatment is performed at low cost. In particular, many imported products have been subjected to such a physical refining process. For example, palm oil that has been subjected to such a process is called RBD (Refined Bleached and Deodorized) palm oil (for example, Patent Document 3). reference).
By the way, fats and oils that have been physically refined as described above (that is, refined fats and oils) are inexpensive, but have not been sufficiently refined. Mostly done.
However, as described above, there is a problem that it is difficult to perform decolorization when the refining process is performed again on the oil and fat that has been once purified. Probably, it is thought that the pigments contained in the fats and oils are polymerized during the distillation performed in the physical refining process to increase the molecular weight.

For example, Patent Document 4 discloses that smectite (activated clay) activated by acid treatment is used as a decoloring agent for vegetable oil or the like, but decolorization for vegetable oil or the like that has not been physically refined. However, no consideration has been given to the decolorization performance of those subjected to physical refining treatment such as RBD palm oil.
Thus, the actual situation is that the decolorization property of the vegetable oil subjected to the physical refining treatment has not been known at all.

  Among various fats and oils, rice oil is known to be difficult to decolorize.

JP 2008-31411 A JP 2005-6510 A JP2011-30482A Special table hei 11-500352

Accordingly, an object of the present invention is to provide a fat and oil bleaching agent that exhibits excellent decolorizing ability with respect to RBD palm oil that is a fat and oil that has been subjected to a physical refining treatment.
Another object of the present invention is to provide a bleaching agent for fats and oils that exhibits excellent bleaching properties even for rice oils that have been conventionally known as fats and oils that are difficult to decolorize.

The present inventors have, as a result of many experiments on bleaching against RBD palm oil and rice oil, with moderate maintaining the layer structure of the smectite, Al ³⁺ amount present between layers (the exchangeable Al ³⁺ amount) By adjusting to an appropriate range, it discovered that the decoloring property with respect to RBD palm oil or rice oil improved, and came to complete this invention.

According to the present invention, the BET specific surface area is made of an acid-treated smectite in a range of 150 m ² / g or more, and the substance amount ratio (SiO ₂ / Al ₂ O ₃ ) in terms of oxides of Si component and Al component is It is in the range of 8.0 to 18.0, and the ratio of exchangeable Al ³⁺ to all Al atoms is in the range of 4.0 × 10 ^{−2 to} 8.0 × 10 ⁻² equivalent%, A fat and oil bleaching agent is provided.

In the bleaching agent for fats and oils of the present invention,
(1) containing exchangeable Al ³⁺ in an amount of 20.0 to 60.0 meq / 100 g;
(2) The ratio of exchangeable Ca ²⁺ to exchangeable Al ³⁺ is suppressed to 60 equivalent% or less, and the ratio of exchangeable Mg ²⁺ to exchangeable Al ³⁺ is suppressed to 60 equivalent% or less.
(3) containing K ⁺ in an amount of 0.30 to 6.0 meq / 100 g;
(4) Use for decolorization of RBD palm oil that has been physically refined,
Or (5) use for decolorizing rice oil,
Is desirable.

  The decolorizing agent of the present invention exhibits excellent decoloring performance with respect to palm oil that has been subjected to physical refining treatment, that is, RBD palm oil. For example, when an RBD palm oil having a light transmittance of 64.1% (with a water transmittance of 100%) is decolored using normal activated clay, as shown in the examples described later. The transmittance is 79.2%, but it exceeds 81% when the amount of exchangeable aluminum is adjusted to a certain range according to the present invention. That is, the transmittance is improved by 2% in the present invention, which is a level that can be visually recognized, and indicates that the decolorization performance is greatly improved.

The decolorizing agent of the present invention alone is excellent in terms of cost because it exhibits excellent decoloring performance with respect to RBD palm oil and does not require the addition of a third component.
Furthermore, as shown in Examples (application examples) described later, the decolorizing agent of the present invention exhibits excellent decoloring properties even with respect to rice oil.

XRD diffractogram of Potash alum. The XRD diffractogram of the activated clay obtained in Comparative Example 1 and Example 2.

Fats for decolorizing agent of the present invention is obtained from the acid treated smectite, i.e. activated clay, acid treatment, the BET specific surface area of 150 meters ² / g or more, in particular increased to about 250~400m ² / g .

In the present invention, in such an acid-treated smectite having a high specific surface area, the amount of exchangeable Al ³⁺ is adjusted to a certain range, specifically, a substance in terms of oxides of Si component and Al component. The quantitative ratio (SiO ₂ / Al ₂ O ₃ ) is in the range of 8.0 to 18.0, particularly 13.0 to 18.0, and the ratio of exchangeable Al ^{3+ to} the total Al atoms is 4.0 × 10 ^{− It is in the range of 2 to} 8.0 × 10 ⁻² equivalent%, particularly 4.0 × 10 ^{−2 to} 7.0 × 10 ⁻² equivalent%.

Ratio of the mass ratio and exchangeable Al ^3+, while smectite unique three-layer structure is suitably maintained without being destroyed, the amount of Al 3+ in the interlayer of smectite ^{(exchangeable} Al ³⁺⁾ increases moderately This means that such increased exchangeability Al ³⁺ provides excellent decolorization to RBD palm oil.
That is, the acid-treated smectite which is the decolorizing agent of the present invention contains Al atoms derived from the basic three-layer structure of smectite (Al atoms forming an AlO ₆ octahedral layer described later). In addition to basic Al atoms (hereinafter sometimes referred to as non-exchangeable Al), ion-exchangeable Al ³⁺ is introduced between the basic three-layer structures of smectite, and the amount thereof is increasing. The improvement in decolorizing property for RBD palm oil due to the increase of exchangeable Al ³⁺ has been found as a phenomenon in many experimental results, and the exact reason has not yet been elucidated. ^{Suppose that} the increase in exchangeable Al ³⁺ results in an increase in the amount of solid acid. That is, it is considered that components that are difficult to remove, such as high molecular weight components, contained in RBD palm oil are effectively removed by the solid acid.

For example, a bleaching agent having too large SiO ₂ / Al ₂ O ₃ satisfies the ratio of the exchangeable Al ^{3+ to} the total Al atoms in the subsequent external addition treatment of Al ³⁺ as a result of excessive structural destruction in the acid treatment. It may be difficult to obtain sufficient decoloring ability. On the other hand, if this ratio is too small, the acid treatment itself is insufficient, so that the specific surface area is small and the decolorization performance may be lowered.

In addition, in order to obtain an exchangeable Al ³⁺ ratio that is excessively larger than the above range, it is necessary to increase the amount of Al ³⁺ by external addition. As a result, impurity ions accompanying the external addition treatment of Al ³⁺ ( For example, an increase in K ⁺ ) results in a decrease in decoloring performance. On the other hand, when the ratio of exchangeable Al ³⁺ is excessively smaller than the above range, it is naturally impossible to show excellent decolorization performance.

In the decolorizing agent of the present invention, the BET specific surface area is increased to the aforementioned range as a result of the smectite being acid-treated. Further, (by nitrogen adsorption method) pore volume in the pore diameter 1.7~100nm is in the range of 0.30~0.50cm ³ / g, bulk density of 0.45~0.70g / cm ³ Is in range.

In addition, bleaching agents of the present invention, in the step of external addition treatment of ^{Al 3+,} can adjust the exchangeable ^{Al 3+} content, ^{Ca 2+} and ^{Mg 2+} contained in the layers are exchanged removed, e.g. The ratio of the exchangeable Ca ^{2+ to} the exchangeable Al ³⁺ is suppressed to 60 equivalent% or less, and the ratio of the exchangeable Mg ^{2+ to} the exchangeable Al ³⁺ is suppressed to 60 equivalent% or less. Moreover, in such a decoloring agent, K ^<+> is contained in an amount of 0.30 to 6.0 meq / 100 g. In general, when the K ⁺ is less than the above range, the amount of exchangeable Al ³⁺ is not sufficiently increased, and the decolorization performance for RBD palm oil may be unsatisfactory. Further, when the amount of K ⁺ is larger than the above range, a lot of impurity ions are introduced by the potassium alum treatment described later, and there is a possibility that the decolorization performance is lowered by such impurity ions.

The total amount of Al atoms, exchangeable Al ³⁺ amount, and other ion amounts contained in the decolorizing agent of the present invention can be measured by a known method shown in Examples described later.
For example, the total amount of Al atoms can be determined by thorough acid treatment of this decoloring agent and decomposed, and the amount of Al atoms contained in the treatment liquid can be determined by atomic absorption or the like. Further, the amount of exchangeable Al ^3+, using potassium chloride to selectively extract exchangeable Al ^3+, determined from the amount of Al contained in the extract.

<Production method of fat and oil bleaching agent>
The fat and oil bleaching agent of the present invention is made of, for example, clay mainly composed of dioctahedral smectite clay mineral, acid-treated under predetermined conditions, and further by external addition treatment of Al ³⁺ using potassium alum. It can be obtained by introducing exchangeable Al ³⁺ .

The dioctahedral smectite clay minerals used as a raw material is believed to volcanic rock and lava is modified under the influence of sea water, consists SiO ₄ tetrahedral layers -AlO ₆ octahedral layer -SiO ₄ tetrahedra layer, In addition, a three-layer structure in which the tetrahedral layer and the octahedral layer are partially replaced with the same type of metal is used as a basic structure (unit layer), and Ca, K, There are cations such as Na and H ⁺ and water molecules coordinated therewith. In addition, since a part of Al in the octahedral layer of the basic three-layer structure is replaced with Mg or Fe ^(II) and a part of Si in the tetrahedral layer is replaced with Al, the crystal lattice is negative. It has a charge, and this negative charge is neutralized by metal cations and H ⁺ existing between the basic layers. Such dioctahedral smectite clay minerals include acid clay, bentonite, and fuller's earth, and exhibit different characteristics depending on the type and amount of metal cations present between metal layers and the amount of H ⁺ . For example, bentonite has a large amount of Na ⁺ present between the basic layers. Therefore, the pH of the dispersion suspended and dispersed in water is high, generally on the high alkali side, and has a high swellability with respect to water. Furthermore, it shows the property of gelling and solidifying. On the other hand, in the acid clay, the amount of H ⁺ present between the basic layers is large, and therefore, the pH of the dispersion suspended and dispersed in water is low, generally on the acidic side, and also exhibits swelling properties with respect to water. However, compared with bentonite, its swelling property is generally low, and it does not cause gelation.

The clay having such a dioctahedral smectite clay mineral as a main component is not particularly limited, and any of the various types described above can be used. In addition, such a raw clay generally has the following composition in terms of oxides, although it varies depending on the origin of the clay, the production area, and the same production area depending on the buried place (face).
SiO _2; 50-70 wt%
Al ₂ O _3; 14~25 wt%
Fe ₂ O ₃ ; 2 to 20% by mass
MgO; 3-7 mass%
CaO; 0.1-3 mass%
Na ₂ O; 0.1 to 3 wt%
K ₂ O; 0.1 to 3 wt%
Other oxides (such as TiO _2); 1 wt% or less Ig-loss (1050 ℃); 5~10 wt%

  A clay raw material mainly composed of dioctahedral smectite clay mineral is subjected to refining operations such as stone sand separation, buoyancy beneficiation, magnetic beneficiation, water tank, wind drought, etc., if necessary, followed by acid treatment.

  The acid treatment can be performed by either a granular activation method or a mud activation method. Hereinafter, the granular active method will be described as an example, but the present invention is not limited to this case.

  In the granular active method, it is necessary to form the raw clay mineral into a granular material suitable for acid treatment in advance prior to contact with the acid. The ore to be mined generally contains about 35 to 40% by mass of moisture, and this moisture becomes a granulation medium for granulating clay.

  Using Onigashi crusher as a crusher, crushing raw ore and kneading clay. For this kneading, a groove roll, a flat roll, or a combination thereof can be used. Next, the kneaded clay is granulated to a predetermined size. The diameter of the granular material is generally in the range of 3 to 10 mm, particularly 5 to 7 mm.

  As a suitable granulator, there is a perforated roll, which has a hole in a pair of rolls, supplies clay to the nip position of the roll, and passes the clay from the outside to the inside of the roll. Granulation is performed to the size of.

By subjecting such a granulated product to acid treatment, a part of the Al component in the basic three-layer structure of smectite is removed as Al ³⁺ , resulting in an increase in specific surface area and an increase in pore volume. Physical properties suitable for adsorption of pigments such as chlorophyll can be ensured.

  The acid treatment is performed by filling a clay granule in a treatment tank and circulating an acid aqueous solution. As the acid aqueous solution, mineral acids such as sulfuric acid, hydrochloric acid and the like, particularly sulfuric acid are used, and the concentration is suitably 14 to 40% by mass. The treatment temperature is in the range of 95 ° C. or less, and the treatment time varies depending on the treatment amount, but the conditions are selected from the range of about 6 to 18 hours.

By the way, in principle, it is possible to adjust the amount of exchangeable Al ³⁺ to the above-mentioned range only by the above-mentioned acid treatment, but the clay mainly composed of dioctahedral smectite clay mineral used as a raw material is natural. In view of the fact that the composition varies depending on the collection location, etc., it is almost impossible to obtain acid-treated smectite that satisfies the above-mentioned conditions. That is, Al atoms in the basic three layers are eluted by acid treatment, and a part of this remains as exchangeable Al ³⁺ , but when adjusting the exchangeable Al ³⁺ amount in this way, Naturally, the structural destruction of the basic three layers occurs, so it is necessary to control the acid treatment conditions (the concentration of the acid used, the temperature, the treatment time, etc.) very strictly. However, the composition of the clay mainly composed of this dioctahedral smectite clay mineral is not constant and will vary depending on the lot, etc., so the acid treatment conditions must be changed each time according to the variation. In fact, industrial implementation is practically difficult.

Therefore, in the present invention, the above acid treatment is performed lightly, and then exchangeable Al ³⁺ is introduced by treatment with potassium alum (ie, external addition treatment of Al ³⁺ ), thereby decolorizing for RBD palm oil. The agent is manufactured.

In such a production method, the mild acid treatment performed prior to the external addition treatment of Al ³⁺ with potassium alum, for example, the ratio of exchangeable Al ^{3+ to} the total Al atoms is 2.0 × 10 ⁻² to 4 It is carried out to such an amount that it is about 0.0 × 10 ⁻² equivalent%.
That is, if this acid treatment is performed too strongly, the structural destruction of the dioctahedral smectite clay mineral proceeds excessively even though the amount of exchangeable Al ³⁺ increases, and as a result, SiO ₂ / Al ₂ O ₃ is reduced. It will deviate from the range mentioned above and will cause the fall of the decoloring performance with respect to RBD palm oil.

After the above acid treatment, the treatment solution containing the acid treatment product is filtered, and the obtained filtrate is immersed or suspended in an aqueous solution of potassium alum, for example, so that the external addition of Al ³⁺ by potassium alum is performed. Processing is performed.

Potash alum used (AlK (SO ₄ ) ₂ .nH ₂ O, n = 12, 10, 6, ₃ , ₂ or 0) is potassium aluminum sulfate, and there are crystal and dry matter (anhydride). Either can be used.
That is, potassium alum is a double salt of sulfuric acid containing potassium together with Al atoms, and is a weakly acidic substance that is easily soluble in water. In this aqueous solution, lightly acid-treated smectite is suspended and dispersed with stirring. Thus, aluminum atoms are introduced as exchangeable ions between the layers of the basic three-layer structure of smectite, and at the same time, K ⁺ is also introduced between the layers. Moreover, since the aqueous solution of potassium alum is weakly acidic, excessive elution of Al atoms in the basic three layers can be effectively suppressed, and structural destruction of the basic three layers can be effectively prevented.
In addition, by this treatment, at least a part of Mg ²⁺ and Ca ²⁺ contained between the layers is removed by ion exchange with Al ³⁺ and K ⁺ .

As described above, the external addition treatment of Al ³⁺ using potassium alum effectively suppresses the structural destruction of the dioctahedral smectite clay mineral while maintaining the amount of exchangeable Al ³⁺ and other physical properties within the above-mentioned range. It can be adjusted.
The effect of introducing exchangeable Al ³⁺ by treatment with such alum alum is obtained in the XRD diffractogram of potassium alum (see FIG. 1), Comparative Example 1 and Example 2 as the exchangeable Al ³⁺ amount increases. Compared with the XRD diffractogram (see FIG. 2) of the obtained activated clay powder, it can be confirmed that the diffraction peak peculiar to potassium alum disappears after the external addition treatment of Al ³⁺ .

In the present invention, the concentration of the aqueous solution of potassium alum used for the external addition treatment of Al ³⁺ of the potassium alum is not particularly limited, but generally, it contains potassium alum at a concentration of about 2 to 6% by mass. The treatment temperature after adding the acid-treated smectite to this aqueous solution may be a temperature at which potassium alum does not precipitate, and is generally room temperature or more, particularly about 25 to 70 ° C. The treatment time varies depending on the concentration and temperature of the potassium alum solution to be used, the treatment amount, etc., and cannot be generally defined, but is usually about 1 to 6 hours. In actual production, the amount of exchangeable Al ³⁺ is measured in advance by a laboratory test, and an appropriate time may be set.

After the above external addition treatment of Al ^3+, the suspension in which the acid-treated smectite is dispersed is washed with water, dried using a generally known method, if necessary, and then pulverized and classified. A decolorizing agent can be obtained.

The decoloring agent thus obtained has the exchangeable Al ³⁺ amount and the like adjusted to the above-mentioned range, and generally has the following chemical composition in terms of oxide.
SiO _2; 60-80 wt%
Al ₂ O ₃ ; 8 to 13% by mass
Fe ₂ O _3; 1~10 wt%
MgO; 1-5 mass%
CaO; 0.1 to 2% by mass
Na ₂ O; 0.1 to 1 wt%
K ₂ O; 0.1 to 2 wt%
Other oxides (such as TiO _2); 1 wt% or less Ig-loss (1050 ℃); 4~8 wt%

The depigmenting agent thus obtained is also called activated clay, and exhibits excellent decoloring properties as a decoloring agent for RBD palm oil, which is imported in large quantities from overseas and used in many applications such as margarine. It also exhibits excellent decolorization performance as a decolorizing agent for rice oil.
Such activated clay has activity as a solid acid and has a large specific surface area and pore volume. Therefore, it can also be used as a catalyst or catalyst support for dehydration, decomposition, polymerization, isomerization, etc. in organic chemical reactions. .

  The invention is illustrated in the following examples. In addition, the measuring method in an Example is as follows.

(1) Specific surface area, pore volume, and bulk density The specific surface area is measured using a TriStar 3000 manufactured by Micromeritics, and the BET method is used from an adsorption branch side nitrogen adsorption isotherm having a relative pressure of 0.05 to 0.25 or less. Analyzed.
The pore volume was measured by a nitrogen adsorption method, and the pore volume having a pore diameter of 1.7 to 100 nm was determined from the adsorption branch side nitrogen adsorption isotherm by the BJH method.
The bulk density is JIS. K. Measurement was carried out in accordance with 6220-1 7.7: 2001, and the bulk density in terms of moisture was determined by the following formula.
Bulk density (g / cm ³ ) = G (1- (M / 100))
G: Measurement value of bulk density (g / cm ³ )
M: 110 ° C. dry moisture (%) of the sample

(2) Chemical composition Analysis of ignition loss, silicon dioxide (SiO ₂ ), and aluminum oxide (Al ₂ O ₃ ) is based on JIS. M.M. Measured according to 8853: 1998. Moreover, atomic absorption method was used for Fe ₂ O ₃ , CaO, MgO, and K ₂ O. The measurement sample was based on a dried product at 110 ° C.

(3) Exchangeable cation content (Al ³⁺ , Mg ²⁺ , Ca ²⁺ , K ⁺ )
Analysis of Al ³⁺ , Mg ²⁺ , and Ca ²⁺ was measured by atomic absorption spectrometry on the leachate obtained using a 1 mol / L KCl solution. Also, ^{K +} was measured using the atomic absorption method to leachate obtained with 1mol _/ L CH 3 COONH ₄ solution. The measurement sample was based on a dried product at 110 ° C.
The ratio of each exchangeable cation was determined from the following formula.
Ratio of exchangeable Al ³⁺ to all Al atoms (equivalent%):
(Exchangeable ^{Al 3+} substance amount) ÷ (total _Al 2 _{O 3} material weight) ÷ 2 × 100
Ratio (equivalent%) of exchangeable Ca ²⁺ to exchangeable Al ³⁺ :
(Exchangeable Ca ²⁺ substance amount) ÷ (exchangeable Al ^{3 +} substance quantity) × 100
Ratio of exchangeable Mg ²⁺ to exchangeable Al ³⁺ (equivalent%):
(Exchangeable Mg ²⁺ substance amount) ÷ (exchangeable Al ^{3 +} substance quantity) × 100

(4) Decoloring test method For the performance test of the decoloring agent, a decoloring tester shown in the figure of the clay handbook 3rd edition, Japan Clay Society edition (Gihodo Publishing) p570 was used. Eight hard glass large test tubes (capacity 200 ml) can be set in the oil bath in the decolorization tester. Each test tube is filled with a corrugated stirrer with a rounded bottom, and the bottom is adjusted with a rubber tube so that it always contacts the bottom of the test tube. Since the eight stirring rods are rotated by a child gear separated from the central parent gear, the rotation speeds are kept exactly the same. A stirring blade for stirring the oil bath is attached under the central master gear, and the temperature in the oil bath is kept uniform. A maximum of 8 decolorization tests can be performed. 30 g of RBD palm oil was sampled in each test tube, 0.6 g of each decolorizing agent sample (2% with respect to the oil) was added and mixed well with a stir bar for decolorization test. Each test tube was set in the above-mentioned decoloring test machine maintained at 110 ° C., stirred for 20 minutes, then taken out from the decoloring test machine, and each decolorized oil was obtained by filtering the mixed slurry of oil and decolorizing agent. . The white light transmittance (relative value when the transmittance of distilled water was 100%) of each decolorized oil was measured with a photoelectric colorimeter type 2C manufactured by Hirama Rika Laboratory Co., Ltd.

(Comparative Example 1)
Clay mainly composed of dioctahedral smectite clay mineral produced in the womb of Niigata Prefecture was used as a raw material, and this raw material was roughly crushed, kneaded and granulated to a diameter of 5 mm. The water content of the obtained granulated product was 37%.
1500 g of this granulated product was filled into a treatment tank, and 2000 ml of 35% by mass sulfuric acid aqueous solution was circulated therein for acid treatment. The treatment temperature at this time was 90 ° C., and the treatment time was 12 hours. After completion of the acid treatment, washing water was circulated through the acid-treated product, followed by washing with water, followed by drying, pulverization and classification at 110 ° C. to obtain an activated clay powder.
The obtained activated clay powder was measured for various physical properties, and the results are shown in Table 1.

Example 1
The acid-treated product (water-containing product before drying) after completion of water washing in Comparative Example 1 was used as a raw material. To 100 g of this acid-treated product, 58 g of a 2.3% by weight aqueous solution of potassium alum was added and treated at room temperature for 4 hours. After completion of the treatment, the treated product was washed with water by a decantation method, and then dried, pulverized and classified at 110 ° C. to obtain an activated clay powder.
The obtained activated clay powder was measured for various physical properties, and the results are shown in Table 1.

(Example 2)
An activated clay powder was obtained in the same manner as in Example 1 except that 106 g of a 3.7% potassium alum aqueous solution was used instead of 58 g of the 2.3 mass% potassium alum aqueous solution in Example 1.
The obtained activated clay powder was measured for various physical properties, and the results are shown in Table 1.

(Application examples)
(5) Decolorization test method for rice oil The oil collected by the examiner is deacidified rice oil, and each decolorizer sample is 0.6 g (2% to oil) or 0.9 g (oil) for each oil. The white light transmittance was measured by the method described in (4) Decoloring test method, except that it was changed to 3%). In addition, the residual amount of chlorophyll in the decolorized oil prepared from the deoxidized rice oil was quantified using a V-630 spectrophotometer manufactured by JASCO Corporation according to the standard oil analysis method 2.9-1996 established by the Japan Oil Chemists' Society. did. It means that chlorophyll is removed effectively, so that this value becomes small. The results are shown in Table 2.

  As shown in Table 2, the bleaching agent of the present invention improves the white light transmittance of the bleached oil even with respect to rice oil, which is known to be difficult to bleach like RBD palm oil. High removal ability and excellent decolorization performance.

Claims (6)

It consists of an acid-treated smectite having a BET specific surface area in the range of 150 m ² / g or more, and the substance amount ratio (SiO ₂ / Al ₂ O ₃ ) in terms of oxide between the Si component and the Al component is 8.0 to 18. A bleaching agent for fats and oils, characterized in that the ratio of exchangeable Al ^{3+ to} the total Al atoms is in the range of 4.0 × 10 ^{−2 to} 8.0 × 10 ⁻² equivalent%. The bleaching agent for fats and oils according to claim 1, comprising exchangeable Al ³⁺ in an amount of 20.0 to 60.0 meq / 100 g. The fat according to claim 1 or 2, wherein the ratio of exchangeable Ca ²⁺ to exchangeable Al ³⁺ is suppressed to 60 equivalent% or less, and the ratio of exchangeable Mg ²⁺ to exchangeable Al ³⁺ is suppressed to 60 equivalent% or less. Depigmenting agent. The bleaching agent for fats and oils according to claim 3, which contains K ⁺ in an amount of 0.30 to 6.0 meq / 100 g.   The bleaching agent for fats and oils according to any one of claims 1 to 4, which is used as a bleaching agent for RBD palm oil.   The bleaching agent for fats and oils according to any one of claims 1 to 4, which is used as a bleaching agent for rice oil.