NL8201457A - HYDRAULIC CEMENT, PROCESS FOR ITS PREPARATION, AND EXCIPIENTS TO BE USED THEREIN. - Google Patents

Description

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Hydraulic cement, process for its preparation, and auxiliary materials to be used therewith.

This invention relates to the fine grinding of hydraulic cements and, more particularly, the use of certain auxiliary materials to increase the efficiency of the grinding and to prevent the grinding cement from baking together.

When processing Portland cement, for example, the cement is usually ground in a semi or unworked state to obtain a fine powder. It is desirable that this grinding is done as efficiently as possible, using as little energy as possible. To this end, chemicals commonly known as "milling aids" are usually added which facilitate the grinding operation, either by increasing the production rate or obtaining finer particles at the same turnover, without any detrimental effect on the properties of the ground product.

The breaking of cement particles during grinding continuously creates fresh surface that has a high energy. The surface forces of the milled particles 20 persist for some time after milling and can lead to baking and / or poor scatterability if not addressed. Cement that is rammed by vibrations, for example during transport in a concrete mill on a trailer, can harden, as it were, and will not flow unless much effort is made to break it up again. It is therefore desirable that the grinding aid also counteracts this tendency to bake.

Many chemicals and chemical mixtures have been proposed as grinding aids and inhibitors of the firing of hydraulic cements such as Portland cement. Examples of such chemicals successfully marketed at 8201457 - 2 - iv include the triethanolammonium salts of acetic acid and of phenol (U.S. Pat. Nos. 3,329,517 and 3,607,326), as well as the ammonium salts of alkylbenzenesulfonic acids and the diethanol ammonium salt of dodecylbenzene-5 sulfonic acid (Japanese Pat. Nos. 7421408 and 7421410).

This invention is based on the discovery that salts formed in the reaction of amines with carboxylic acids with aromatic groups are excellent grinding aids for hydraulic cements such as Portland cement. The presence of such salts in the ground cement also inhibits the baking together. Such salts further give the advantage that the carboxylic acid portion thereof is in many cases available as a product left over from the distillation of coal, which is less sensitive to price fluctuations and shortages that are characteristic today of the petroleum derived chemicals.

Most preferred as a grinding aid according to the invention is an ammonium salt of an aromatic carboxylic acid which is produced as a by-product in the preparation of phthalic anhydride. That by-product, which is essentially a mixture of benzoic acid and phthalic anhydride, is readily available as it has hitherto been of limited application. In addition, this by-product is formed in a process with naphthalene as a starting material, which is available from coal tar.

The grinding aids according to the invention are prepared by mixing the carboxylic acid with an aromatic group with an amine, whereby essentially a neutral ammonium salt is formed. The starting materials can be pure chemicals, but also mixtures of substances.

The amines to be used according to the invention can be primary, secondary and tertiary aliphatic or aromatic amines, and are preferably alkanolamines, as well as mixtures thereof. Useful amines can be represented by 35 8201457 γ · 'if 4 - 3 - «2 (A) Rj - N - R3 and (B) R4N - R5 where Rj is hydrogen or an alkyl, hydroxyalkyl, alkaryl or aryl group, R2 is hydrogen or an alkyl or hydroxyalkyl group, R2 is hydrogen or a hydroxy, alkyl, alkanol or aryl group, R2 is NH corresponding to pyrrolidine, pyrroline, pyrrole, morpholine, piperidine or piperazine and R ,. hydrogen or an alkyl or hydroxyalkyl group. The "aryl" here may be phenyl or naphthyl. One or more of the hydrogen atoms of the aryl group may be passed through a substituent such as nitro, halo (preferably chlorine), alkyl (preferably 1 to 5 carbon atoms) best methyl), aryl, amino or alkoxy (preferably 1 to 5 carbon atoms) have been replaced In addition, pyridazine, pyrimidine and pyridine and the like compounds in which Sen or more hydrogen atoms are replaced by hydroxy or alkyl groups are 00k useful for preparing the auxiliaries according to the invention The indicated pyrrole, pyrrolino, pyrrolidino, morpholino and piperidino groups can be substituted in known manner.

A particularly preferred amine for the preparation of the excipients of the invention is a residue left over from the commercial preparation of alkanolamines as described in U.S. Pat. No. 3,329,517. This residue can be obtained by the ammonolysis or amination of ethylene oxide, the reduction of nitro alcohols, the reduction of aminoaldehydes, ketones and esters, and in the reaction of halohydrins with ammonia or amines. The precise composition of the residue may vary within certain limits, and by "ethanolamines" in this specification is primarily meant mixtures containing one or more mono-, di- or triethanolamines, preferably 40 to 85% by volume. triethanolamine. In general, such a residue is predominantly triethanolamine. A particularly preferred residue is a mixture of mono-, di- and triethanol 8201457-4 amine which is commercially available and has the following chemical and physical properties:

Triethanolamine 45 to 55% by volume

Equivalent weight 129 to 139 5 Tertiary amine 6.2 to 7.0 meq./g

Water maximum 0.5 wt% S.6. 1,135

The aromatic carboxylic acids to be reacted with these amines include both the monocarboxylic acids and the polycarboxylic acids with one or more aromatic groups in the molecule. Examples of aryl groups are phenyl, benzyl, naphthyl, etc. These carboxylic acids may additionally have substituents such as alkyl, halogen, nitro, hydroxy, etc., so long as it has no adverse effect on the intended use. Examples of such aromatic carboxylic acids are benzoic acid, phthalic acid, the alkylbenzene carboxylic acids and also the aryl substituted fatty acids such as naphthalene acetic acid and mandelic acid. Mixtures of such acids are also good. In addition, the anhydrides of these acids can be used, but anhydride may then need to be converted to the acid first.

A particularly preferred carboxylic acid for the preparation of the adjuvants of the invention is the by-product of the preparation of phthalic anhydride by oxidation of naphthalene, generally in the presence of a catalyst. At the end of this process, the oxidation product is distilled to separate high purity anhydride. A by-product of this distillation, sometimes referred to in the industry as "phthalic lites", is a mixture of benzoic acid and phthalic acid hydride. Due to impurities, this by-product has limited applicability, and its toxicity also makes it difficult to get rid of it. It has been found that, after a treatment to convert the phthalic anhydride therein to acid, it is an ideal material for the preparation of the adjuvant of the invention. The by-product is commercially available, and its 8201457-5 application in cement, in which it eventually becomes trapped (in structures, etc.), is environmentally friendly processing. Moreover, this by-product is obtained from a raw material, namely naphthalene, which originates from coal tar, which avoids many problems which occur with chemicals which can only be obtained from petroleum.

The above by-product "phthalic lites" mainly consists of a mixture of benzoic acid and phthalic acid hydride. The exact proportions of these components in the mixture can vary widely, from 99: 1 to 1:99. It has been found desirable to convert the anhydride in this by-product to the acid reaction before the reaction with the amine, if this does not occur during the reaction with amine esters, resulting in products which are less good grinding aids. The conversion of the by-product "phthalic lites" by hydrolysis is preferably done by melting the by-product mixture (about 110 ° C), making it immediately easily transportable, pumpable, etc., and hot water (about 80 ° C) C) to add. After cooling, the amine or amine mixture is added, whereby essentially a mixture of ammonium benzoate and ammonium phthalate is formed.

The ammonium salt according to the invention is ground together with the cement in the concrete mixer, which increases the grinding efficiency and also achieves other advantages, namely less tendency to bake together. The additives according to the invention are particularly suitable when used with Portland cement, a group of hydraulic cements consisting essentially of two calcium silicates and a smaller proportion of calcium aluminate. These cements are prepared by heating an intimate mixture of finely divided calcium source (limestone) and clay together, creating the "clinker".

The clinker is ground, with the addition of about 2% gypsum or other form of calcium sulfate, giving the desired curing properties in the final cement. It is up to the clinker that the adjuvant according to the invention is preferably added to make the grinding more efficient and to prevent the final product from baking together.

The auxiliaries according to the invention can be used in both solid and liquid form. For convenience, the additive is a solution in water, allowing precise dimensions in the flow of spoil. The addition is done either before grinding or during grinding together with the cement. If the adjuvant is only intended to prevent the baking together, the addition thereof can take place at any suitable moment of the process.

The adjuvant according to the invention is successfully used over a wide range, from 0.001% to 1%, based on the weight of cement (weight 15 by weight). In a particularly preferred embodiment, between 0.004 and 0.04% by weight is used. Higher levels are used when grinding to a relatively high specific surface area, and the amount of adjuvant is limited only by the desired specific surface area and the desired degree of scatterability.

By "baking" here is meant the agglomeration and adhesion of the particles, for example during transport of large quantities. The bonding is a result of the surface forces, which are believed to be largely generated during the grinding of the cement. This baking together is determined as follows:

100 g of the cement is placed in a 250 ml Erlenmeyer flask on top of an adjustable vibrator. The cement flask is vibrated for 15 seconds, then placed in a rotary clamp with the axis of the flask horizontally. The flask is then rotated on its axis until the cement pressed against the bottom of the flask collapses. The stock is rotated through angles of 180 ° with a frequency of 100 strokes per minute. The number of strokes of 180 ° required to pour the cement into one is called the "sticking number". The higher the number, the more the cement was attached.

8201457 - 7 -

The invention is now further illustrated by the following examples.

Example I

In a series of tests, 5 different aromatic acids were first reacted with a triethanolamine mixture to form a salt, and grinding tests were carried out with those salts and Portland cement in a laboratory mill.

The triethanolamine mixture was a residue obtained in the aforementioned ethanolamine preparation. Four different vowels (A to D in Table A) from four different manufacturers were used. In each run, 3325 g of clinker (finer than 0.84 mm) were ground together with 175 g of gypsum and the indicated amount of triethanol ammonium salt. That salt was added before grinding. As bianco 15, each of vowels A to D was ground with gypsum but without adjuvant, and each adjuvant test was compared with the corresponding bianco. Also, the conditions during grinding (number of revolutions, between 5000 and 10,000, depending on the type of clinker) were the same for each clinker. The grinding was done at 99 ° C and the specific area in cm / g was measured before and after grinding. In the presence of a grinding aid, the specific surface area was always greater than without the aid, and that increase, in%, is given in Table A for each combination. All tests were done at least in duplicate, 25 and many of them in triplicate. The preparation of the hydrolyzed "phthalic lites" is described in Example II.

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Table A

2% surface area (cm / g) to bianco

Clinker Grinding Aid Dose Test Test Test Gem.

_ (%) 1 2 3 _ A Triethanolammonium- 0.025 6.7 8.6 7.3 7.5 salt of phthalic acid A Triethanolammonium- 0.014 3.5 1.8 - 2.7 salt of phthalic acid A Commercial product 0.025 9, 8 7.8 9.3 9.0 A Commercial product 0.013 2.2 2.3 - 2.3 A Triethanolammonium- 0.025 -5.7 7.3 - 6.5 salt of naphthalene acetic acid A Triethanolammonium- 0.025 6.9 8.5 - 7.7 salt of benzoic acid A Triethanolammonium - 0.015 3.1 6.0 6.5 5.2 salt of hydrolysed "phthalic lites" A Commercial product 0.015 6.3 6.3 8.1 6.9 B Triethanol ammonium- 0.015 8.9 9.3 8.9 9.0 Salt of hydrolysed "phthalic lites" B Commercial product 0.015 5.8 8.3 10.7 8.3 C Triethanol ammonium- 0.015 6.1 5.0 8.7 6.6 salt of hydrolysed "phthalic lites" C Commercial product 0.015 7.8 5.9 7.0 6.9 D Triethanol ammonium- 0.015 8.2 8.5 7.1 7.9 salt of hydro- lysed "phthalic lites" D Commercial product 0.015 6.4 7.7 8.6 7.6 A Triethanol ammonium- 0.025 4.9 6.4 - 5.7 salt of naphthalene sulfonic acid 8201457 • ο »- 9 -

Example II

Two methods can be used to prepare the triethanol ammonium salts of hydrolysed "phthalic lites", the choice of which is determined by the equipment available. The data given in this example refers to a 1000 g serving, although in practice batches up to 250 kg have been prepared by both methods.

Method 1 10 Step 1: Melt 292 g of "phthalic lites" and heat the molten material to between 110 ° and 115 ° C.

Step 2: Add 20 g of hot water (93-100 ° C) to the molten material with vigorous stirring.

Step 3: Monitor the temperature of the reaction mixture. In the beginning, since an exothermic hydrolysis takes place, it rises, then it becomes constant as the thermal equilibrium is reached, and finally it decreases as the hydrolysis comes to an end.

Step 4: After complete hydrolysis (which appears to be the decrease in the reaction temperature), add 448 g of triethanolamine with moderate stirring.

Step 5: When the reaction temperature has dropped below 90 ° C, add 240 g of water.

25 Method 2

Step 1: Heat 260 g of water to between 75 ° and 100 ° C.

Step 2; While stirring vigorously, add 292 g of molten "phthalic lites" to the hot water. The temperature of that molten material should be between 110 ° and 115 ° C.

Step 3: Follow the temperature of the reaction mixture as in Step 3 of Method 1.

Step 4: When the reaction temperature has dropped to 70 ° C, slowly add 448 g of triethanol-35 amine with moderate stirring. The rate of this addition must be set so that the temperature of the mixture does not exceed 100 ° C.

Example III

The suitability of the adjuvants according to the invention to prevent caking has been tested. The manner in which this testing was done was described prior to Example I. Table B shows the results of these tests with cement mixtures from clinker A, B and D. The lower the sticking number, the better the adjuvant as inhibitor of the firing.

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label B

Cement Grinding Aid Dose Clinker Feed Number _ (%) _ A None (bianco) - 30 A Triethanolammonium Salt 0.025 5 of Naphthalene Acetic Acid A Triethanolammonium Salt 0.025 2 of Benzoic Acid A Triethanolammonium Salt 0.025 3 of Phthalic Acid A Commercial Product 0.025 5 A Commercial Product 0.015 9 A Triethanol ammonium salt 0.015 7 of hydrolysed "phthalic lites" B None (bianco) - 14 B Triethanol ammonium salt 0.015 9 of hydrolysed "phthalic lites" B Commercial product 0.015 14 D None (bianco) - 29 D Triethanol ammonium salt 0.015 11 of hydrolyzed "phthalic lites" D Handelsprodukt 0.015 8 8201457

Claims (15)

1. A water-curing cement mixture containing a small amount of substituted ammonium salt of an organic acid as auxiliary material for grinding, characterized in that the grinding aid contains the salt of an amine with a carboxylic acid containing an aromatic group is. The cement mixture according to claim 1, which is predominantly Portland cement. Cement mixture according to claim 1 or 2, characterized in that the amine is an alkanolamine or mixture of alkanolamines. Cement mixture according to any one of the preceding claims, characterized in that the carboxylic acid is a monocarboxylic acid or a dicarboxylic acid with a benzene or naphthalene core or an aryl-substituted aliphatic acid. Cement mixture according to any one of the preceding claims, characterized in that the carboxylic acid with aromatic group is benzoic acid, phthalic acid, naphthalene acetic acid or a mixture thereof. Cement mixture according to any one of the preceding claims, characterized in that it is between 0.001% and 1% (by weight of dry cement) of a salt of an amine with an aromatic carboxylic acid. Cement mixture according to any one of the preceding claims, characterized in that the aromatic carboxylic acid is a by-product of the preparation of phthalic anhydride. Cement mixture according to claim 7, characterized in that the by-product of the phthalic anhydride preparation is a distilled product. Cement mixture according to any one of claims 3 to 8, characterized in that the amine is triethanolamine or a mixture thereof with other amines. Cement mixture according to any one of claims 3 to 9, characterized in that the amine is the residue of an ethanolamine preparation 8201457-13. 11. Process for grinding cement using the salt of an amine and an organic carboxylic acid as an auxiliary substance, characterized in that the auxiliary substance is the salt of an amine with a carboxylic acid containing an aromatic group. 12. Process for the preparation of salts of amines with organic acids, which can serve as auxiliary substances in the grinding of cement, characterized in that an amine is reacted with a mixture of aromatic carboxylic acids obtained as a by-product at the preparation of phthalic anhydride. 13. Process according to claim 12, characterized in that the amine is an alkanolamine or mixture of alkanolamines. 14. Method mainly according to description and / or examples. 15. Mixtures mainly according to description and / or examples. 20 8201457