JPS5836916A - Silicate with high oil absorbency and its manufacture - Google Patents

Abstract

PURPOSE:To inexpensively manufacture a silicate with high oil absorbency by forming an alkaline earth metallic silicate in the 1st stage using fly ash, etc. as starting materials and by increasing the SiO2 content of the silicate in the 2nd stage. CONSTITUTION:Amorphous silicic acid contg. >=50% alkali soluble component or an amorphous silicate such as fly ash is dispersed in a soln. of sodium hydroxide or sodium silicate, and after adding Ca and Mg hydroxides, they are hydrothermally reacted under pressure to form Ca-Mg silicate. To the silicate is added separately prepared silica sol, and they are reacted with heating and stirring to increase the molar ratio of SiO2/CaO. Thus, a ternary system silicate with high oil absorbency is obtd. This silicate consists of SiO2, CaO and MgO in (1-3)/1 molar ratio of SiO2/CaO and (1-2)/1 molar ratio of CaO/MgO, and it absorbs oil by 200-600cc per 100g when measured in accordance with JISK5101.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves a first step of subjecting silicic acid or silicate containing a large amount of alkali-soluble components to a hydrothermal reaction under pressure with an alkaline earth metal hydroxide, and a process of mixing and heating a separately prepared silicate sol. ,
The oil absorption amount according to JIS K5101 obtained by combining with the second step of stirring reaction is 200 to 600 ec.
The present invention relates to a highly oil-absorbing silicate of 71GOf and a method for producing the same.

Strongly deliquescent dyes, pigments, anti-caking agents such as feed or salt, or retention agents for liquid active substances, or inorganic substances that serve as a matrix for liquids with a solid content of less than 30% and an appearance of powder; Alternatively, pigments with high oil or liquid absorption properties are desired as carriers for insecticides or as main materials for heat insulators, and conventionally JIS K5
In terms of oil absorption according to 101, silicic anhydride has the highest 180
~20/1()Ol, and its low hydrous silicic acid is 150~1
80cc/100f.

Calcium silicate and some aluminum silicate are 100~
150cc/100 Pt synthesized calcium or magnesium carbonate 50~100''7100).

20-50cc/10()P of natural silicates, carbonaceous salts, etc.
In this case, mainly silicic acid or silicate having an oil absorption of 100''/100F or more fulfilled its function as a highly oil-absorbing pigment.

However, even with silicic anhydride, which has the highest oil absorption of 200″/100t, the solid content is more than 30.

Considering the production problems caused by the gas phase method, it is inevitable that the production cost will be high, and there are also problems in terms of pollution.

Furthermore, from a functional standpoint, it did not fall into the category of highly powdered liquids, and its anti-caking effect did not meet the high requirements.

According to the present invention, it is possible to effectively utilize relatively inexpensive and abundant raw materials such as fly ash, ashestone, and magnesium in seawater, for which conventional cement admixtures were only used at a pressure similar to that of cement admixtures. At the cost, it can be expected to have the same or more than 6 times the effect.

The manufacturing method of the present invention consists of the following two steps, and each step will be explained in detail below.

First step: 2 to 101 g of one or more crystallographically amorphous silicic acids or silicates containing 50 or more alkali-soluble components (hereinafter referred to as weight) in terms of caustic soda.
The solids are dispersed in a solution of caustic soda or sodium silicate at a concentration of 2 to 5 silicate. In this case, the alkali-soluble component refers to a silicic acid component that dissolves in caustic soda at a concentration of 10%.

For this alkaline suspension of silicic acid or silicate, t, Cα
Add a 1-10% aqueous suspension of calcium and magnesium hydrate with a molar ratio of 0/M % to t-2/l (hereinafter all molar ratios), and then stir and mix. After adjusting the total concentration to 2-30g6.

Put it in a pressure gourd and add 1 to 5 q Yu-3 (gauge pressure) to 2 to 40
A time-added hydrothermal reaction is carried out.

The amorphous silicic acid or silicate containing many alkali-soluble components used in this first step includes fly ash, which is a fine ash collected from the flue gas during combustion of okiya fuel coal, as well as shirasu, silicate, Swelling soil.

Examples include silica gel, amorphous diatomaceous earth, and clay minerals. Crystalline silicic acid or silicates containing less than 50 alkali-soluble components have poor reactivity with alkaline earth metals, and it is difficult to produce the highly oil-absorbing silicates of the present invention from these.

It is necessary to use caustic soda or sodium silicate as a solution to disperse these silicic acids or silicates to a concentration of 2 to 5 capsules, and the concentration of silicic acid or silicates is 5 to 5.
If the concentration of caustic soda or sodium silicate is less than 29 II in terms of caustic soda, it is necessary to increase the pressure and take extra time for the pressurized hydrothermal reaction, resulting in a disadvantage in terms of manufacturing costs. If the concentration is less than 2- and the concentration of caustic soda or sodium silicate exceeds 10-, an oil absorption amount of 200 cc/100 F cannot be obtained.

Furthermore, the molar ratio of calcium and magnesium hydroxide to be reacted with these silicic acids or silicates is CaO/My
It is necessary to have a ratio of 1 to 2/1 in terms of O. It is desirable to consist of a third-order subsystem including the following. However, in some cases, the final composition may allow the inclusion of aluminum and other pure components within 104.

Also, the molar ratio of Sin27Ggo is 0.5 to t5 in the first step.
/1゜The absolute condition is to set it to 1 to 371 in the second step,
If this condition is not met, it is impossible to produce the desired highly oil-absorbing silicate. After stirring and mixing silicic acid or silicates with calcium and magnesium hydroxides in a caustic soda or sodium silicate solution, the total concentration is adjusted to a range of 2 to 60 and placed in a pressurized box, but if necessary, the mixed suspension is It is preferable to heat the mixture at 80 to 90 C for 1 to 2 hours, dehydrate it with a filter press, and then subject it to a pressurized hydrothermal reaction as a concentrate.

The conditions for the pressurized hydrothermal reaction are 1 to 50 #/c♂ (gauge pressure) for 2 to 40 hours, and if 1 to #/& is less than 2 hours, it is 50 to #/c♂ or more than 40 hours. In this case, it is impossible to obtain a highly oil-absorbing silicate with a final value of 20 Dec/100 F or more.

Second step Calcium and magnesium silicate obtained in the first step are
After making an aqueous suspension of ~10%, add 2~10% silica sol obtained by reacting sodium silicate with hydrochloric acid or calcium chloride, and after stirring vigorously for 60~60 minutes, dehydrate, dry, and crush. To produce a highly oil-absorbing silicate having S s O2/CcLO of 1 to 3/1 and Ga07/Mff) of 1 to 2/l and an oil absorption of 200 to 600 cc//100 F through two steps. I can do it.

The present invention provides a highly oil-absorbing silicate obtained by combining these first and second steps and a method for producing the same, and the first embodiment thereof is shown below.

Example 1 In the first step, an alkali-soluble component is dispersed in a caustic soda solution having a concentration of 80% amorphous frying powder to a solid content of 34%.

Next K OaO/110 is 15/1 and 59! A mixed aqueous suspension of calcium hydroxide and magnesium hydroxide at a certain concentration was added so that this fly ash suspension KSiO,/CaO became a guest, and was heated at 80C for 1 hour.

Dehydration was performed using a filter press to obtain a cake-like product with a solid content of 27 ml. . This was placed in a pressure cooker and subjected to a pressurized hydrothermal reaction at 5 kf/cm'' (gauge pressure) for 10 hours.

After making the calcium and magnesium silicates obtained in this first step into an aqueous suspension with a concentration of 3 ginseng.

In the second step, a 3-concentration silicic acid sol obtained by reacting 20 U of hydrochloric acid with No. 5 water glass was added, stirred vigorously for 60 minutes, dehydrated with a filter press, dried with a dryer, and decomposed with a hammer mill. Crushing K Yosu S s 02. /(E
A highly oil-absorbing silicate having an aO ratio of 2.5/1, an OgO/MtO ratio of t5/1, and an oil absorption amount of 500 cc/100F was produced.

Examples 2 to 4 Table 1 shows the relationship between different reaction conditions and the oil absorption amount of the obtained silicate in the same reaction as in Example 1. Note that items not described have the same values as in Example 1.

Comparative Examples 1 to 8 In the same reaction as in Example 1, the relationship between the reaction conditions that deviate from the scope of the present invention and the oil absorption amount of the obtained silicate was determined in the second example.
Shown in the table. Items not listed have the same values as in Example 1.

Comparative example 9 An example of producing a silicate in which only the first step of Example 1 was carried out.

Comparative Example 10 Commercially available silicic anhydride (trade name: Aerosilure USA, product of Aerosteticals Inc.).

As is clear from the results in Tables 1 and 2.

The oil absorption amount of the highly oil-absorbing silicate obtained by the present invention is 25
0 to 500 cc/100 t, and it can be seen that all of them show significantly higher oil absorption than the commercially available silicic anhydride "Aerosil", which has an oil absorption of 190#/100 t.

Claims (1)

[Scope of Claims] t. A first step in which a suspension of silicic acid or silicate containing a large amount of alkali-soluble components in a caustic soda or sodium silicate solution undergoes a pressurized hydrothermal reaction to form an alkaline earth metal hydroxide; JISK5101K manufactured by the second step of mixing silicic acid sol, heating, stirring and reacting
A highly oil-absorbing silicate with an oil absorption of 200 to 600 cc7100 f. 2. The highly oil-absorbing silicate according to claim 1, which has an alkali-soluble component of 5091 or more, is crystallographically amorphous, and is Cape Fryassier silicic acid or a silicate. 5. Composition is at least S&Ox #0αO, Myo
It consists of a six-component system with a molar ratio of S&02/Cα0 of 1 to
3/1 and Ca. 2. The highly oil-absorbing silicate according to claim 1, wherein the molar ratio is 1 to 2/M. The first step involves a pressurized hydrothermal reaction between a suspension of silicic acid or silicate containing a large amount of alkali-soluble components in a caustic soda or sodium silicate solution and an alkaline earth metal hydroxide, and a silicate sol is mixed with the suspension and heated. , the oil absorption according to JIS K5101 is 2, which consists of the second step of stirring and reacting.
00-600ee:/100) A method for producing a highly oil-absorbing silicate. 5. The method for producing a highly oil-absorbing silicate according to claim 4, wherein the alkali-soluble component is 50% or more, is crystallographically amorphous, and is a silicic acid or silicate such as fly ash. 6. Composition is small tt<string Stow I ago e
MfIo') Consists of S component system, E3i02/G
5. The method for producing a highly oil-absorbing silicate according to claim 4, wherein the molar ratio of aO is 1 to 3/1 and the molar ratio of Ga07M is 1 to 2/l. l In the suspension of silicic acid or silicate in caustic soda or sodium silicate solution in the first step. The highly absorbent oil according to claim 4, wherein the caustic soda or sodium silicate has a caustic soda equivalent concentration of 2 to 10 (by weight), and the silicic acid or silicate has a solid content concentration of 2 to 5 (by weight). Method for producing polysilicates. a Silicic acid or silicate and alkaline earth metal hydroxide, 1 to 50 to 2 to 40 #/cat” (gauge pressure)
A method for producing a highly oil-absorbing silicate according to claim 4, which comprises combining a first step of carrying out a time-pressure hydrothermal reaction and a second step of mixing and reacting the reaction product with another silicic acid sol. . 9 E3i0. /CaO% ratio α5~1
A silicate with a molar ratio of 5/1°CtXO/Myo of 1-2/l is prepared, and in the second step, the molar ratio of 5tO2/CeLO is 1 to V1°. /1. The method for producing a highly oil-absorbing silicate according to claim 4.