FI61505C - FOERFARANDE FOER FRAMSTAELLNING AV KALCIUMALUMINATHYDRATER KALCIUMSALIKATHYDRATER OCH / ELLER DESSA FOERENINGARS SAMUTFAELLNINGAR - Google Patents

Description

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France-France (FR) 733796k (71) Lafarge, Soei £ te Ahonyine, 28, rue jSmile Menier, Paris l6eme, France-France (FR) (72) Jacques Baudouin, Montelimar, Jean Pierre Caspar, Le Teil, France-France (FR) (7k) Leitzinger Oy (5k) Method for the preparation of calcium aluminate hydrates, calcium silicate hydrates and / or co-mixtures of these compounds - Förfarande för framställning av kalciumaluminathydrater, calcium silikathydrater och / eller dessa föreningars sam

The invention relates to a process for the preparation of calcium aluminate hydrates, calcium silicate hydrates and / or co-mixtures of these compounds in finely divided form, in particular as fillers, in which water is added to anhydrous calcium aluminate, anhydrous Portland cement or at a temperature between about 10 and 100 ° C and optionally drying the resulting suspension. In particular, the invention relates to a process for the preparation of simple or complex hydrates in finely divided form. The powders prepared can act as inert mineral-containing base fillers, starting from simple or complex salts, called anhydrates, which are obtained in particular in the cementitious and / or refractory industry and / or in the gypsum industry.

Cements or hydraulic silicate or clay soil binders are known to be suitable for hydration in a compact form and are used due to their binder properties and high strength. Said change made by different concrete manufacturers and users results in products that are desirable due to their tightness, durability, pressure resistance, binder properties, and so on. Various use studies show that the cement granules first hydrate very rapidly after a certain latency, called the setting time, after which the hydration becomes increasingly slow.

M 5 O 5 Hydration in this way results in gels or fine entangled crystals which solidify the environment, reducing the possible movement of ions, which usually results in a slowing down of chemical reactions. Hydration, which has begun rapidly, takes a very long time to complete completely, and in clay soil cements consisting mainly of hemi- and monocalcium aluminates, the hydration reaction is still noticeable after 6 months or one year. Portland cement undergoes a hydration reaction for several decades.

Under laboratory conditions, hydrates of hydraulic binders can be prepared in fine form for experimental purposes. For this, it is sufficient that the conventional hydration is carried out in the presence of excess water with or without stirring, decomposition, etc. As an example of such model preparation under laboratory conditions, reference should be made to "Journal of Chemistry Society" 1950, pp. 3682-3690 and "The Chemistry of Cement and Conorete" 3rd edition, F.M. LEA, pp. 180 ....

In all of these methods, the granulate of anhydrate material is dispersed in water, with or without agitation. This material dissolves slowly and the hydrate precipitates slowly by a chemical reaction. The above-mentioned LEA publication states on pages 180 and 181 that tri-calcium silicate can be completely hydrated in a ball crusher in the presence of excess water within one or two days. Dicalcium silicate, a major ingredient in Portland cement, hydrates under these conditions within 46 days.

The above methods are performed on a laboratory scale only; starting from a given quantity of substance and after suitable work steps which have been accelerated by more or less known physical means (temperature) or chemical means (accelerator), they make it possible, by methods which are still discontinuous, to obtain a hydrate corresponding to the anhydrate used. Numerous experiments and studies which - because hydrates are the synthesis of several ions from anhydrates and water taken from the reaction medium - have led to the knowledge that hydrates of a hydraulic binder formed on hydration are formed on the surfaces of the least soluble anhydrate granules. at the points where the solubility yield of the fastest-formed salts is reached. This means that the surfaces of the least reactive anhydrate granules come into less and less contact with water, and that for this reason the reaction rate of hydration itself decreases and the reaction is delayed.

The Applicant has further found that only the finest granules of cement hydrate very rapidly, while slightly larger granules are surrounded by a hydrate layer, with the result that their final solution is determined by ion diffusion through this hydrate layer. This solution is thus determined by the well-known Fick's law and, in terms of time, takes an infinitely long time.

The materials currently used as mineral fillers are generally kaolin, pyrogenic kaolin, natural or synthetic calcium silicates such as wollastonite, natural or synthetic calcium carbonates, lime, quartz, dolomite, barium sulphate, etc. kaolin. Other products are obtained from solution by precipitation starting from ions obtained by dissolving highly soluble salts, for example sodium silicate and sodium aluminate, lime and aluminum sulphate. Finally, and this is the most common case, others are obtained by grinding naturally occurring rock species to the desired fineness on a dry or moist road. In this way, the finest powders are obtained from carbonates, lime, dolomite, quartz, etc., which can be used as fillers or in fillers. Because of the high fineness, in the order of microns, these disintegration operations become very expensive and difficult.

Based on the above presentation and findings, the applicant came up with the idea of exploiting the effect of water on calcium salt anhydrate in the production of better quality mineral fillers, which are sparingly soluble products from the hydraulic binders and / or refractories and / or gypsum industry; these binders are decomposed only to moderate fineness (not to the micron range). However, the desired micron fineness of hydrate-based fillers is achieved by exploiting the effect of water on the anhydrates so that water acts on the surface of the anhydrate granules by entering the solution and maintaining this very rapid hydration rate at the onset of the reaction. for larger particles it is best to mix or move very vigorously, preferably in the presence of an inert mineral! in economic terms).

The inventive features of the method are summarized in claim 1.

Lime is added as needed to keep the stoichiometry required for the reaction correct. This addition of lime is generally not necessary when using Portland cement or its clinker.

The following can be used as starting material:

Synthetic calcium aluminates prepared in view of the invention or obtained in the manufacture of refractory hydraulic binders and prepared as such or in a mixture, namely: 3 CaO, Al 2 O 3 to 12 CaO, 7 Al 2 -C aO, Al 2 -CaO, 2 Al 2 O 3.

Since calcium aluminate contains too little lime in relation to the amount of lime required for the stoichiometry of the reaction to be determined later, it makes sense to add lime as quicklime or slaked lime, pure or impure, the impurities usually consisting of calcium carbonates and magnesium carbonates. Calcium silicates can also be added as important sources of lime, especially Portland cement, which is known to release lime upon hydration of the calcium silicate it contains. In this way, suitable mixtures are obtained.

The invention can also be used in the preparation of hydrates from Portland cements or their decomposed clinkers or also in the preparation of clay soil cements or their decomposed clinkers consisting mainly of calcium aluminates.

Starting materials that are white are best used. Such products for sale are e.g. Portland white cement, clay white cement, refractory clay soil cement, etc. All these white products of this type can be used, but for the purposes of the invention it is recommended to use products with a white matter degree of 75505 or more relative to the magnesium oxide standard. The invention thus makes it possible to produce a very fine, particularly white powder or powder with a degree of whiteness of 90% or even more than the magnesium oxide standard. These finely divided powders consist mainly of hydrates and can be used in all industries where such substances are used as fillers, for example in the paint industry, paper industry, plastics industry, rubber industry, insecticides, detergents, cosmetics, etc.

The invention thus makes it possible to prepare by co-precipitation hydrate mixtures which contain essentially at least one mixture of calcium aluminates and calcium silicates. According to the invention, for example, it is possible to prepare very rapidly the following hydrates: CaO, Al 2 O 3, n H 2 O (8 n <13 13), 4 CaO, Al 2 O 3, n H 2 O (n is usually 10 to 19); 3 CaO, Al 2 O 3, 6 H 2 O; 2 CaO, Al 2 O 3, 8 H 2 O; x CaO, y SiO 2 z H 2 O such as 3 CaO, 2 SiO 2, 3H 2 O or CaO, SiO 2 n H 2 O 'known as "tobermorite".

All of these products can be produced either alone or as a mixture, depending on the purity and amount of Portland cement or clay soil cement used as a starting material. Chemical reactions are known and are described, for example, in F.M. In the said publication cited by the LEA or in the T.D. In Robson's publication "High Alumina Cements".

The following are some embodiments of carrying out the process according to the invention in which various hydrates are prepared as fillers. For the sake of brevity, CaO is hereinafter abbreviated as "C", Al 2 "A" and H 2 O "H".

Example 1 Preparation of C2AHg This example describes the preparation of a fine and inert powder in the micron range. The powder consists of a hydrate corresponding to the chemical composition of formula 2 CaO, Al 2 O 3, 8 H 2 O.

Refractory clay soil cement with the following composition is used: 6 61505

CaO: 35.3 parts by weight Al 2 O 3: 64.4

Fe 2 O 3: 0.06 volatile ingredients: 0.24 parts by weight.

Aluminum and calcium are bound to each other mainly in the form of CaO, Al 2 O 3, which is called monocalcium aluminate anhydrate * The chemical reaction is as follows:

CaO, Al 2 O 3 + Ca (OH) 2 + 7 H 2 O - ^ 2 CaO, Al 2, 8 Η ,, Ο (1) For this purpose, calcium aluminate is placed in a tank equipped with a slow mixer as a white powder which has been dried and crushed. industrially in a ball crusher to a fineness of 9 3000 cm / g. Water is added until a paste with a dry matter content of 40% is obtained and the whole reaction is carried out at a temperature below 35 ° C. In this context, it should be noted that aluminate is known to hydrate very slowly due to a self-slowing reaction caused by the formation of hydrate crystals on the surface of the anhydrate granules, and that while this fine powder is expected to hydrate completely, X-ray analysis the reaction is not complete.

According to the invention, the dispersion prepared in this way can be fed to an abrasive device for micronutrients, known as a "sand crusher". When the dispersion is allowed to pass through very rapidly, it has been found that this device does not cause the anhydrate granules to crush, which can be reinforced very easily, but still peels off the surrounding hydrate layer, leaving the released anhydrate surfaces exposed to water again. Depending on the size of the particles used, the dispersion is passed through so many devices that complete hydration is achieved. In the example below, after an average time of one hour, the dispersion was passed to a first scrubber loaded with zirconia balls. After half an hour passed through the dispersion obtained this time to another, structurally similar device, which was arranged in cascade with the first. In this way, CaO 2 O 3 was completely hydrated to a mixture of primary hydrates using very little energy and a hydration time of 2 hours. Lime milk (40% slurry of industrial lime) was then added so that the amount of lime added corresponded to the amount required for the stoichiometry of the equilibrium (1). This lime was gradually added so that the amount of calcium oxide in the solution always remained below 0.5 g / liter. This step was performed simply by stirring, and after one hour of reaction, X-ray diffraction analysis showed that a slurry of white powder had been obtained.

This suspension can be filtered in a filter press at 10 bar with filters made of polypropylene to obtain a thick paste. However, for example, it is preferable to dry the suspension directly by melting to obtain a fine powder having the following properties:

Appearance: white, fine powder

Composition: 2 CaO, Al 2 O 8, 8 H 2 O.

Morphology: micron-sized particles in small hexagonal plates Fineness: granulometry range 0 - 9 μ

Average particle diameter 2 μ Degree of whiteness (photovoltaic) 8 = 94.2% pH of a 10% aqueous solution: 10.5 Burning loss at 1000 ° C: 40% by weight Refractive index: n = 1.52 3

Specific gravity: 1.97 g / cm

Example 2 Preparation of CH 2 Cl 2

The following starting materials are used to prepare the hydrate of the invention having the chemical formula CaO, Al 2 O 6, 6 H 2 O: one or more calcium aluminate CaO, 2 Al 2 O 2, CaO, Al 2 O 2; 12 CaO, 7 Al 2 O; 3 CaO, A1203 as a source of alumina, the formula being supplemented as necessary by the addition of quicklime or slaked lime or a substance which may release lime. Finally, more water is added.

In this example, refractory clay soil cement having the following chemical composition is used as the calcium aluminate: 615 0 5 8

SiO 2: 0.1 part by weight total: 72.34 parts by weight

CaO: 26.7

Fe 2 O 3: 0.03 "CO 2: 0.25

Na 2 O + K 2 O: 0.27 "wherein the alumina and lime are combined anhydrate CaO, A 2 ° 3 Ca® '^ A ^ 2 ^ 3 *

Mix 450 parts by weight of industrial cement powder crushed to a fineness of 3000 cm / g (specific surface area according to Blainen) and 550 parts by weight of commercially available industrial calcium hydroxide Ca (OH) 2 · This gives 1000 parts of "anhydrate" a so-called mixture which gives 1154 parts of hydrate after reacting with water. The anhydrate is kneaded with water to give a somewhat flowable paste with a dry matter content of 35% by weight. This paste is added to a stainless steel container equipped with a classic slow mixer, for example a paddle mixer that rotates at 5 rpm. The vessel is equipped with a jacket and the whole apparatus is brought to a temperature of 70 to 80 ° C.

As in the first example, the mixture is simply stirred and the chemical reaction is allowed to proceed. After a reaction time of 12 hours, it can be stated at this temperature that hydration has not yet taken place completely: This can be demonstrated by X-ray diffraction studies, which show that there is still some dicalcium aluminate remaining.

However, in the method according to the invention, after 15 minutes the charge is tipped into a corundum ball crusher filled with corundum balls. In this subtlety in question, such a crusher is known to be very inefficient; however, it causes a central abrasion of the added particles, which - as explained above - allows the chemical reaction to be blocked. After 5 hours of hydration, it can be seen by radiocrystallographic X-ray analysis that the anhydrates are completely hydrated. The final product consists mainly of the desired hydrate 3 CaO, Al 2 O 3, 6 H 2 O.

9 615 0 5

According to one method, a fluidized bed with microspheres is used to improve the abrasion phenomenon. A sand crusher or a vibratory crusher can be used for this purpose: In the first example, a 250 liter stainless steel crusher and zirconia as the abrasive were used. The average waiting time of the preformed paste was 011 1 hour, the average residence time in the fluidized bed was 4 minutes, the waiting time of the product was 20 minutes, the average residence time in another device of similar structure was 4 minutes.

With regard to this step, it could be established by similar analytical methods that even now the complete Hydra to i turn i nen of the added product had been obtained.

The process according to the invention gives a suspension of a white powder which can be filtered and dried by conventional methods. The product according to the invention obtained from said binders had the following characteristics:

Composition: tricalcium aluminate hexahydrate 3 CaO, Al ^ O ^, 6 1 ^ 0

Appearance: micro-white powder

Morphology: cubic microcrystals

Granulometry: average particle diameter 1.6 μ

Degree of whiteness (photovolt): 94.4%, 495 μ

Burning loss at 1000 ° C: 24.6% 3 Specific gravity of the filler: 2.49 g / cm Refractive index: 1.60 2

Specific surface area (method B.E.T.): 10.9 cm / g.

It should be noted that these properties correspond to the properties of a very good white mineral filler.

Example 3 Preparation of C, AHn ^ - 4 13_

A mixture of the anhydrates CaO, Al 2 O 3 and 12 CaO, 7 Al 2 O 3, obtained as an industrial refractory cement and crushed to an industrial fineness of 2800 crrf / 'g (according to Blaine), is reacted with water and lime so that the following reaction takes place:

CaO, Al 2 O 3 + 3 Ca (OH) 2 + water- (4 CaO, Al 2, 13 H 2 O) 12 CaO, 7 Al 2 O 3 + 16 Ca (OH) 2 + water → 7 (4 CaO, Al 2, 13 H 2 O) ).

The calcium aluminate hydrate obtained is characterized by the formula 4 CaO, 615 0 5 10 A ^ O ^, n ^ 0, where n, which is usually 13, can be between 10 20. Water was added in such an amount that the total dry matter content of the paste was 20%.

According to Example 1, operations were carried out at temperatures below 35 ° C, but this time a lime dispersion was added at the beginning of mixing to obtain an aqueous solution with a CaO concentration in water of more than 0.5 g / l.

The same apparatus as in Example 1 is then used, in which case it was found that the added anhydrate was completely hydrated after being passed twice through the scrubber for a total time of 3 hours. The obtained powder in suspension was then dried by spraying at a higher temperature, whereby it was found to have the following properties:

Appearance: micro-white powder

Composition: mainly hydrate 4 CaO, Al 2 O 2, 13 H 2 O.

Morphology: microfine hexagonal plates

Fineness: 51% less than 2 μ 95% less than 8 μ

Degree of whiteness (photovoltaics): 8 = 93.8% pH of a 10% aqueous solution: 11.3 Burning loss at 1000 ° C: 42%

Refractive index: n = 1.53

Specific gravity: d = 2.02 g / cm 2.

The aqueous dispersion of this filler has rheologically important properties due to its high viscosity.

Example 4 This example describes the accelerated preparation of intermediate hydrates that can be used in the preparation of tobermorite-based fillers.

Hydrate white Portland cement with a composition of: 11 61 5 O 5

SiO2 23.7%

Fe 2 O 3 0.28% SO 3 1.2% 1 Al 2 O 3 2.7%

CaO 69.3%

Other 2.62% and with a fineness corresponding to the following granulometry: less than: 2 μ: 4 / i: 8 μ: 16 ju: 32 μ i 64; u% 14 22 36 57 80 97 This hydration was carried out in a vessel to which cement anhydrate could be continuously fed . Water was added in such an amount that the cement anhydrate concentration was 20% and the paste thus obtained remained in suspension. The reaction took place at a temperature between 60 and 70 ° C.

If, in this study, the hydration of the anhydrate was performed in the apparatus until it was expected to be completely complete, then stirring had to be continued — as should be noted in this context — for several months, and the method is not profitable.

However, according to the invention, the reaction is allowed to start, for example within 4 hours, while preventing the particles from settling.

The aqueous suspension is then added to the scrubber described in Example 1: It can be seen that after a total time of 3 hours a fine white hydrate powder is obtained which no longer contains anhydrate. This powder consisted of a mixture of tobermorite and lime. Thermal differential analysis showed that 100 parts of white Portland cement yielded 130.5 parts of hydrate with 75 parts of tobermorite and 55 parts of lime, i. it was a mixture containing 57.5% tobermorite and 42.5% lime.

This gave a mixture of intermediate hydrates suitable for the preparation of fillers very quickly.

The same mixture of calcium aluminates and the same equipment as in Example 2 are used, but white Portland cement is added as a source of lime, as in Example 4.

12 61 505

According to Example 4, a mixture of said aluminate was prepared starting from a mixture of 75 parts of tobermorite and 55 parts of lime obtained from 100 parts of hydrated white cement; operating under exactly the same conditions to give a mixture of 59% 3 CaO, Al 2 O 3, 6 L 2 O and 41% tobermorite.

The following examples illustrate various excipients formed from hydrates prepared in accordance with the invention.

Example 6

Hydrate 2 CaO, Al 2 O 2, 8 K 2 O (octahydrate dicalcium aluminate) occurs as microfine, crystallized plates in a hexagonal system. The product obtained according to Example 1 is a lamellar micro-fine filler which is of particular interest due to its morphology, degree of whiteness and softness.

Of the possible use examples, the use of a filler as a paper coating agent is particularly advantageous.

Two coating liquids 1 and 2 were prepared, corresponding to the following formulas:

Pigment: 100 parts by weight Starch: 10 "

Latex: 10 "

In formula 1, good kaolin has been added as a filler, which is common in paper coating. Preparation 2 used an excipient prepared according to the invention.

Koostumus_1__2_

Dry matter content 58% 55% pH 6.3 11.1

Fineness 100% 8 μ 100% 8 μ

Viscosity Brookfield 10 rpm 9500 cp 9200 cp 100 "" 1350 cp 1280 cp A sheet of paper AFNOR VII was coated. The following results were obtained: 13 61505 (1) (2) _ _ Coating weight, g / m / page 15 15

Opacity 97.3 97.9

Degree of whiteness 80.2 87.1

Ulkonäkö_satinoitu_satinoitu_

The results clarify the quality of the filler according to the invention; compared to kaolin, it has the advantage of: - unusual degree of whiteness - good opacity, better than kaolin - alkalinity of the filler, which is recommended for the use of dispersants - low density of the filler.

Another possibility of using the hydrate 2 CaO, A ^ O ^, 8 1 ^ 0 in the production of paints is: a) Grease dyes for the protection of the surfaces of wood, wood presses, etc. can be produced with good durability, good adhesion and easy application. Pasteurization takes place by dispersion. No disintegration, for example with micronutrients, is required due to the fineness of the filler prepared according to the invention.

Composition:

Glycerin oil, dry matter content 65% 15,4-hydrogen chloride octate 0.05 1) cobalt octoate 0.1

Anti - skin agent 0.05

Heavy petrol 10

Filler according to the invention 55

Microtalkium 40 μ 5

Terebentine essence 0.4

Dioctyl phthalate 2

Solvent Solvesso 150 (ESSO) 10

Heavy petrol 2

A total of 100

Dry matter content 70%

Pigment ratio: binder P / L 6/1 14 615 0 5 b) A white satin emulsion dye was prepared.

Composition

Anionic dispersant, dry matter content 10% 4.1

Collacral VL (BASF), dry matter content 20% 6.7

Methylcellulose, 4% solution 6

Fatty acid ester emulsion, 20% 8

Defoamer 0.8

Water 10

Filler 30 according to the invention

Titanium oxide 10

Ethyl glycol acetate 2 Tall oil 1

Heavy petrol 1

Vinyl emulsion, dry matter content 50% 50

Water for dilution q.s.

Features

Dry matter content 52.4%

Pigment / binder ratio P / L 1.43 / 1 The rheology of the dye is thixotropic. Application is simple and takes place without the formation of droplets. The whiteness and opacity are very good.

Example 7 Use of CaO, Al 2 O 3/13 1 ^ 0. This filler occurs in the form of microfine, lamellar particles which, in aqueous solution, produce high viscosity at low dry matter content.

The filler prepared according to Example 3 dispersed 20 parts by weight per 100 parts by weight of water in water. A thick paste with a viscosity of 10 rpm was obtained. (Brookf input: 11,050 cp 100 "" "2,500 cp.

This product can therefore replace Benton and bentonite and other thickeners in all uses of these products: Paints, inks, additives for drilling fluids, anti-settling thickeners, etc.

is 615 0 5

Non-dripping colors were prepared having the following composition:

Titanium dioxide, rutile 10

Microfine dolomite 10

Barium sulphate 10

Filler according to the invention (4 CaO, Al 2 O 3, 13 H 2 O) 10

Glycerol resin (modified with desiccant oil) 10

Heavy gasoline 8 Tall oil 1.5

Glycolyethylene 0.5

Drying agent and anti - skinning agent

Heavy gasoline depending on viscosity This dye can be applied as a thick top color by spraying or as a higher dilution as a base color. The color is easy to handle and does not drip even when applied thick.

Example 8 3 Use of CaO, Al 2 O 3, 6 H 2 O.

1) a: In accordance with the methods normally used in the preparation of coating liquids, the following coating liquid was tested: - Filler according to the invention (3 CaO, Al 2 O 3, 6 H 2 O) 100

Water 100

Latex emulsion, dry matter content 50% 20 Starch, dry matter content 25% 40

Calcium stearate 1

Anti-cryptogenic agent 0.1 so. coating liquid with a dry matter content of 46.2% and a pH of 11 without additions to correct the pH.

Viscosity, 10 rpm. Brookfield 1550 cp "100" "" 120 cp 16 615 0 5

After coating paper weighing 70 g, the weight of the coating was 12 g / m 2 / page.

Paper opacity according to Elrepho (coated only one page): 88.2%.

Whiteness, Elrepho: 90.7%.

b: For comparison, three coating composition mixtures were prepared in order to compare the filler according to the invention with the commercially available kaolin. The following excipients were prepared:

Koostumus_1_2__3_

Kaolin "Dinkie A" 100 80 0

Filler according to the invention_0_20_3Ό0_ In these three cases the composition of the coating liquid was: - Pigment 100 parts by weight - Starch 10 "dry - Latex 12" dry

The results are given in the following table:

Koostumus_1_2__3_

Dry matter content 58% 55% 55% pH 6.3 10 11.1

Fineness 100% <8 μ: 100% <8 μ: 100% <8

Viscosity, Brookfield 10 rpm. 9500 8500 3000 100 "" 1350 1500 700 Coated paper: __ Coated layer weight, g / m2 / page 16.9 17 17

Opacity 97.40 97.75 97.9

Valkoisuusaste__79,7_81,3__83_

Appearance neutral great matte

The results show the quality of the filler according to the invention; its advantages in paper coating compared to kaolin are: 17 61505 - excellent degree of whiteness - good opacity, better than kaolin - alkalinity of the filler, which is advantageous for the dispersant - lower binder requirement - low viscosity: The coating liquid is thixotropic - coated paper - coated paper higher dry matter content.

2) The synthetic filler according to the invention can also be used in colors, taking into account its interesting properties (rheology-degree of whiteness-opacity-matte of the dispersion).

The applicant has manufactured a mata inner wall joint which has been able to reduce the titanium oxide content, resulting in a very inexpensive dye because it did not drip.

Composition

Water 18 parts by weight

Low viscosity hydroxyethylcellulose (7% solution) 4

Defoamer 0.2

Butyl glycol 1

Filler according to the invention 32

Titanium oxide 9

Vinyl emulsion, dry matter content 50% 30

Heavy petrol 1.3

Water to improve viscosity 4

A total of 99.5

The resulting color has the following properties:

Brookfield viscosity: 10 rpm: 2300 cp 100 "": 560 cp

Pigment / binder ratio: P / L = 2.68 / 1 pH: 10.5

Dry matter content: 56.5%

Density: 1.35

Degree of whiteness, Elrepho: 91 18 61 505 No grinding is required in the preparation of this mixture due to the very high fineness of the filler according to the invention. The only action required is rapid dispersion upon addition, which then slows down as the vinyl emulsion is added.

These examples show that the fillers prepared according to the invention are particularly well suited, for example, in cases such as paper coating in admixture with conventional kaolins and in other conventional blends. Due to the basicity of the filler, it is possible to omit the adjustment of the pH and good stability is obtained for the emulsion used. The opacity and whiteness values obtained clearly indicate the importance of the filler according to the invention.

The mineral-containing products obtained according to the invention, whether chemically known or not, are white mineral-containing and microfine materials which are inert and which provide advantageous fillers for numerous industrial applications.

Claims (2)

19 61 505 A process for preparing calcium aluminate hydrates, calcium silicate hydrate and / or. co-mixtures of these compounds in finely divided form, in particular, as fillers in which water is added to anhydrous calcium aluminate, anhydrous Portland cement or clay soil after being crushed to a finely fine, optionally lime is added and the mass is stirred vigorously at a temperature between about 10 and 100 ° C and optionally drying the suspension obtained, characterized in that an amount of water is added to the starting material which is only moderately finely crushed to form a paste with a dry matter content of 5 to 70% by weight and that mixing is sufficient to remove a hydrate layer formed on the surface of the original particles. Process according to Claim 1, characterized in that the mixing is not so vigorous as to cause the granules of the original material to break.