WO1981001000A1

WO1981001000A1 - Process for producing calcium silicate moldings

Info

Publication number: WO1981001000A1
Application number: PCT/JP1979/000260
Authority: WO
Inventors: Y Oguri; M Abe; S Inoue; J Saito; T Kawahara
Original assignee: Mitsubishi Chem Ind; Y Oguri; M Abe; S Inoue; J Saito; T Kawahara
Priority date: 1979-10-12
Filing date: 1979-10-12
Publication date: 1981-04-16
Also published as: NL7920096A

Abstract

Calcium silicate moldings with a low bulk density, high heat resistance, and excellent mechanical strength are produced by previously dispersing a lime material in water under specific conditions, adding a silicic acid material thereto, heating the mixture to cause a reaction and obtain an aqueous slurry containing calcium silicate hydrate and having specific properties, then dehydrating and molding this aqueous slurry and subjecting it to steam curing under pressure to crystallize calcium silicate hydrate.

Description

― Details Title of invention

Manufacturing technology of canosilicate silicate molded body

The present invention relates to a method for producing a calcium silicate molded body. More specifically, the present invention relates to a method for producing a calcium silicate molded body having low bulk density, excellent heat resistance, excellent mechanical strength and dimensional stability, and thus suitable as a heat insulating material and a heat insulating material. You.

; Its

Scenery technology

Calcium silicate molded products, especially those mainly composed of zonotrite, are suitable as heat insulating materials and heat insulating materials because they have heat resistance of / c or more. is there. In general, a calcium silicate molded body used for a heat insulating material and a heat insulating material is required to have low thermal conductivity. For this purpose, it is necessary to produce a compact having a low bulk density, but it is extremely difficult to produce such a compact.

Recently, as a method for producing such a molded article, an aqueous slurry containing a specific calcium silicate hydrate is dehydrated, then steam-cured, and then subjected to steam curing. To crystallize calcium hydrate]? Manufacture calcium silicate molded body

RE CM? I _ f _kt V / IPO Methods have been proposed. This method is extremely advantageous, but depending on the type and composition of the calcareous or siliceous raw materials, the production conditions for aqueous slurry containing a specific calcium silicate hydrate There was a drawback that it was difficult to set

Therefore, the present inventors have further studied and found that it is sufficient to disperse calcareous raw materials in water under specific conditions in advance, and reached the present invention. Disclosure of the invention

The gist of the present invention is that a sedimentary volume obtained by reacting a calcareous raw material and a siliceous raw material dispersed in water with heating is obtained.

After dehydration molding of the aqueous slurry containing calcium silicate hydrate composed of the above tobamolite group compound, it is subjected to steam curing under pressure. In the method of crystallizing calcium silicate hydrate to produce a calcium silicate molded body, the calcareous raw material is predicted to be at least twice the weight of the calcareous raw material. ~ /

Formula (I) in water at a temperature of C

T ≥ 30 (I) [where, 3 indicates water temperature (J), and T is the required stirring time.

— (Indicate the time)], and stir and disperse it for a period of time that satisfies

WIPO — — Exist.

Hereinafter, the present invention will be described in detail.

In the method of the present invention, the calcareous raw material is previously stirred and dispersed in water at a temperature of at least / q weight and at a temperature of ~ / 00 C with respect to the calcareous raw material for a time satisfying the above formula (I). It is necessary. Particularly preferred is / ~ ^ weight times and calci ... Equation (Π) in water at a temperature of J "C

This is a method of stirring and dispersing for a time that satisfies the following condition: 300ΘT 0 (E) [wherein 0 and T have the same meaning as in the above formula (I)]. Stirring method can adopt the known methods, strength about had solids precipitated ¾ may ₀ calcareous material of stirring the first

It is not necessary to add to water at a temperature of 30 ° C. or higher, and it is also possible to raise the temperature to a predetermined temperature after adding B to water at a lower temperature. As the calcareous raw material, any of the well-known ones such as quicklime, slaked lime and carbite slag can be used, but quicklime is particularly preferred.

By using the slurry containing the calcareous raw material obtained in this way, it is possible to easily and stably produce a canolite silicate molded body having excellent mechanical strength and low bulk density according to a method described later. 0

In the present invention, then, the slurry containing the calcareous raw material is used. The seed and the siliceous raw material are mixed and reacted under heating.

The siliceous raw materials include natural products such as diatomaceous earth and silica stone or silicon dust, and hydrosilicofluoric acid and aluminum hydroxide by-produced in the wet phosphoric acid production process. And other industrial by-products such as silica (hereinafter simply referred to as wet phosphoric acid by-product silica).

The mixing molar ratio of the siliceous raw material and calcareous raw material (Cao / Siog) is when zonotrite is desired as crystals of silicate hydrate in the final molded product. Is usually within the range of cf ~ /].?, But it is usually used when crystalline tongues and molytes are desired. There is a range of 0 to 7 ~

The amount of water for dispersing the two protozoa should be not less than / weight times the solid content of the raw material, and is particularly preferable to be in the range of / 7 to weight times.o Of course, i If the water in the slurry containing the calcareous raw material is not enough to make it work, more water may be added.

An aqueous slurry containing calcium silicate hydrate can be obtained by heating and reacting the two raw materials dispersed in water. In the method of the present invention, first, an aqueous slurry is prepared. The sedimentation volume of calcium sulfate hydrate in the reactor must be at least / scA / 9.

Here, the sedimentation volume is a value calculated by the following equation (I).

OMPI WIFO — —

V

Settling volume =

¥ In the formula (I), w is the total weight of the solid content of the raw material (for example, quicklime + siliceous raw material) (If a calcareous raw material other than quicklime is used, convert it to quicklime to obtain the total weight.)

V is the volume occupied by the solids that settled after allowing the slurry obtained after the reaction to stand for 2 hours. In practice, this is usually determined as follows. First, a slurry of the total weight obtained after the reaction was collected in a mess cylinder and allowed to stand for 2 hours, and the volume ed occupied by the sedimented solids was measured. Next formula (IV)! )calculate.

V.

Settling volume

W represents the total weight of the raw materials in the same manner as in formula (i). As a method of increasing the sedimentation volume to / SC / 9 or more, the reaction is stirred with / or more, especially / 'to ~ <2ί, optimally / έ, to = 2 / ク. There is a method to carry out. At that time, the reaction system needs to be kept in a liquid state, and thus the reaction is performed under pressure.

Second, the calcium silicate hydrate in the aqueous slurry must be a compound of tobermorite glue ο A variety of calcium silicate hydrates are known. J9, generally by HFW Taylor, “The Chemistry One-Year-Old Bussem fΙΙΘ Chemi B t ry of Cements) "Volume / Volume / Sorted according to the classification shown in the table on page 2 c. Toba moriite gel compounds include toba moriite gel, C_s- H (Π) _Λ C — S — Η (I) and crystalline tobermorite, but any of them may be used. Calcium silicate hydrate is composed of topamolite glue — C — S — Η (Π) → C _ s-Η (I) → / / Α tobamolite (crystalline Since the transition usually takes place in the order of (topamorite) → zonotrite, it is sufficient to adjust the reaction temperature and time to obtain the desired hydrate. That is, when the reaction temperature is increased or the reaction time is increased, the hydrate is shifted in the direction of the arrow (-). When the reaction is carried out in a temperature range for achieving the second condition, a compound of the tobamolite group is usually obtained. However, if the reaction temperature is particularly high, the reaction time is particularly long, so zonotrite can be obtained. In that case, the temperature may be lowered or the reaction time may be shortened. If crystalline tobermorite is desired as a crystal in the final molded product, calcium silicate hydrate in slurry is tobermorite gel, C— Must be S — H (I) or C – S — H (Π).

In the method of the present invention, the calcium silicate hydrate in the aqueous slurry satisfies both the first and second conditions described above.

OMPI However, even if either one of these conditions is lacking, a molded article having low bulk density and excellent mechanical strength cannot be obtained.

The obtained aqueous slurry is subjected to pressure dehydration molding after adding reinforcing fibers according to a conventional method. Of course, the reinforcing fibers may be added before the production of the aqueous slurry. The molding pressure is usually in the range of / ~ = 200 k ^ cd o-. Adjustment of the bulk density of the molded article is performed by adjusting the strength stroke of the pressure molding machine. Any of various well-known reinforcing fibers can be used. For example, asbestos, rock wool, glass fibers, and the like are used. Usually, it is added so that ^. ~ / ^ Weight is contained in the final molded article.

Next, the obtained molded body is subjected to water vapor curing under pressure according to a conventional method, so-called stoichiometric curing. This water vapor curing causes crystallization of the hydrated form. Hydrate is a tobamorite gel, 0 — S — H (I) or C — S — H

In the case of (Π), the hydrate can be transferred to crystalline tobamorite or zonotorite, and in the case of crystalline tobamorite, the hydrate can be transferred to zonotorite. is necessary. By the crystallization by the steam curing, a compact having a low bulk density and excellent mechanical strength can be obtained. Generally, the higher the water vapor pressure, the shorter the reaction time, but it is usually in the range of ~ 0 ^ / cA Qr. If zonotrite is desired as the crystal of the final molded product, «« 2 ~ 1 ^ / CT? G ”, crystalline tobermorite If desired, ~ S kg./c Qr steam is preferred. Under these conditions, the above-mentioned transition is usually easily performed. Such cases are very rare if the transition is not performed as desired, but if, for example, zonotriite is desired and crystalline topomolite is obtained. Should the steam pressure be increased or the steam curing time extended, or should zonotrite be obtained when crystalline topomolite is desired, or vice versa? What is necessary is just to shorten the time of steam curing.

In applications where high heat resistance is required, it is preferable to convert to zonotrite.

Although the present invention has been described in detail, according to the method of the present invention, bulk density click. ² Qu Zed less, typically about 0. / F / ai and has the following輊量property / ^ or In general, it is possible to stably obtain a calcium silicate molded body having a bending strength of about / ^ / cA. The molded body obtained is also extremely excellent in terms of heat insulation.] 9 Also, it has sufficient fire resistance even at temperatures of ク to ク ^ C, so it is fire-resistant insulation and building materials. A wide range of applications such as can be expected. BEST MODE FOR CARRYING OUT THE INVENTION

Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to its gist.]

OMPI It is not something to be done.

In the examples, “parts” and “” indicate “weight parts” and “weight”, respectively.

Example / ~ and Comparative Example / ~

The amount of quicklime (CaOO) shown in Table / Table was added to the amount of water shown in Table / Table and stirred under the conditions shown in Table / Table to produce a slurry containing calcareous raw material. After adding the siliceous raw material in the amount shown in Table / Table to this slurry, water was added so that the total amount of water became c2 J "weight times the solid content. The siliceous raw material was used. implementation Te examples / and Comparative examples / through equation phosphate byproduct Shi Li force dampening in 2 (composition _{S i0 2? 7. <f,} ΛΖ 2 0 3 0,, loss on ignition /. ° h) using the exemplary example = 2 to and comparative example 0 "silica stone is put to (Tokai Kogyo Co., Ltd., trademark Izu Tokuko (D), the composition Si0 ₂ 7.0 ^ a in _{_{2 0 3:? L, Fe}} 2 0 3 0. / ^ ajo).

Next, this and was obtained the suspension Nigoeki containing calcareous material and siliceous material O in one preparative click rate blanking _{/ S kg. / Cd Q N} 0 0 under the condition = 2 hours stirring the reaction by filtration Thus, an aqueous slurry containing calcium silicate hydrate having the properties shown in Tables / Tables was obtained. In the comparative example, zonotrite crystals were obtained with the reaction time as time.

An aqueous slurry containing calcium silicate hydrate and an amosite asbestos portion previously dispersed in water and a lock (available from Nippon Steel Chemical Co., Ltd.) Hui par) / add part After the addition, dehydration molding was performed. This compact is charged into an autoclave, and the steam pressure / ZCT! After steam curing under the conditions of 1 for 1 hour, it was dried at / C for 1 hour.

With respect to the obtained calcium silicate compact, the type, bulk density and bending strength of the crystal as main components are shown in Table / Table.

No./Table

ΟΙνίΡΙ

WIPO A Table / Table (continued)

— — Industrial applicability

As described above, the method of the present invention is particularly useful as a method for producing a calcium silicate molded body suitable as a heat insulating material and a heat insulating material.

WIPO

Claims

Sought

(1) Silicic acid consisting of a compound of the tobamolite group with a sedimentation volume of / cd / f or more obtained by reacting a calcareous material and a siliceous material dispersed in water with heating. An aqueous slurry containing calcium hydrate is subjected to dehydration molding, followed by steam curing under pressure.] 9 Crystallize calcium silicate hydrate In the method for producing a molded body of lime, the calcareous raw material is prepared in advance in water at a temperature of J0 to / 00'C at least twice the weight of the calcareous raw material and at a temperature of J0 to / 00'C.

Θ 'T ≥ 3 0 (I)

[Where, e indicates the water temperature (° C), and τ is the required stirring time.

(Time)]. A method for manufacturing a calcium silicate molded body characterized by stirring and dispersing for a time that satisfies

(2) The method for producing a silica-calcium molded body according to the claims / claims, wherein the calcareous raw material is quicklime.

(3) In the method for producing a calcium silicate molded article according to the claims (1) or (2), an aqueous slurry containing calcium silicate hydrate is reinforced. How to add fiber.

OM? I WIPO