NZ200319A

NZ200319A - Hydraulic cement compositions containing aromatic acid amine salts as grinding aids

Info

Publication number: NZ200319A
Application number: NZ200319A
Authority: NZ
Inventors: B A Lange
Original assignee: Grace W R & Co
Priority date: 1981-06-02
Filing date: 1982-04-16
Publication date: 1985-07-12
Also published as: DK246582A; DK158508B; BR8203033A; ES8307714A1; BE893372A; AT383111B; FR2506752A1; DK158508C; AR227242A1; DE3217517A1; SG70586G; AU8254582A; KR840000447A; CH650758A5; MY8700082A; MY8700050A; ZA822399B; IT1148174B; NL8201457A; DE3217517C2

Description

<div class="application article clearfix" id="description"> New Zealand Paient Spedficaiion for Paient Number £00319 2 003 1 Priority Dat^n.;: 2:7 f. 7VX Complete Specification Fifed: Class; Publication Date: ....... F.O. Journal, Mo: ./. 7. i... If© n §I6S Patents Form No.5 NEW ZEALAND PATENTS ACT 19 53 COMPLETE SPECIFICATION "GRINDING AIDS FOR HYDRAULIC CEMENTS" -IjWE W.R. GRACE AND CO., a Connecticut corporation of 62 Whittemore Avenue, Cambridge, Massachusetts 02140, U.S.A. hereby declare the invention, for which i/we pray that a patent may be granted to -rea/us, , and the method by which it is to be performed, to be particularly described in and by the following statement:- -1- 2C0S19 F10 BACKGROUND OF THE INVENTION This invention relates to the grinding of hydraulic cements to reduce the particle size thereof, and more particularly to the addition of certain chemical additives to such cements during the grinding thereof to improve the efficiency of the grinding operation and also the "pack-set" characteristics of the ground cement. In the processing of Portland cement for example, a grinding operation is generally employed either in the unprocessed or semiprocessed state to reduce the cement to relatively small particle size. It is desirable in this grinding step to have as efficient an operation as possible, that is, to reduce the particular mineral to the desired size using as little energy as possible. Toward this end, it is customary to add chemicals known as "grinding aids" during the grinding operation which facilitate the operation either by increasing the rate of production, or by increasing the fineness of the particles at the same rate of production, without having adverse effects on the properties of the ground product. Cleavage of the cement particles during grinding exposes fresh or nascent surfaces which have high energy. The surface forces of the ground particles persist for some time after grinding and can lead to compaction or "pack-set" and/or poor fluidity if they are not reduced. Cement particles when compacted by vibration, e.g., when transported in a hopper car often become semirigid and will not flow until considerable mechanical effort has been applied to break up the compaction. It is desirable therefore if the "grinding aid" also acts to reduce 30 this tendency to compact or "pack-set". Many chemicals and chemical mixtures have been suggested for use as grinding aids and pack-set inhibitors for hydraulic cements such as Portland cement. Examples of such chemicals-which have been successfully commercially applied include trie-'^sythanolamine salts of acetic acid (N.Z. Patent 140578 and triethanolamine salts of phenol (U.S. Patent 3,607,326 to Serafin). Also, the use of amine salts of alkyl benzene sul-phonic acid and the diethanolamine salt of dodecyl benzene sul-39 phonic acid in particular have been suggested as grinding aids 20 'r 2C0S19 for cements f. SUMMARY OF THE INVENTION The present invention is based upon the discovery that % salts formed by reacting aromatic group-containing carboxylic acids with amines are excellent grinding aids in the grinding of hydraulic cements such as Portland cement. The presence of such salts in the ground cement also acts to inhibit the tendency of ground cement to compact or "pack-set". Such salts moreover offer the advantage that the carboxylic acid reactant is obtainable commercially in many instances from starting materials. (benzene, toluene, xyleres, etc.) produced in the distillation of coal, and therefore avoid .the price fluctuations and shortages currently characteristic of chemicals derived solely from petroleum. Most preferred as a grinding aid according to the invention is an aromatic group-containing carboxylic acid amine salt prepared by reacting an amine and an acid component obtained as a by-product in a commercial'process to produce phthalic anhydride. The by-product, which is principally a mixture of benzoic acid and phthalic anhydride, is economically available since uses for the by-product material are limited. Moreover, the by-product is obtained from a process which uses naphthalene as a starting material which is obtainable from coal tars. DETAILED DESCRIPTION The grinding aids of the invention are prepared by mixing the aromatic group-containing carboxylic acid component and the amine to obtain an essentially neutral amine salt. The starting materials may be pure chemicals or chemical mixtures. • The amines employed in the present invention include primary, secondary and tertiary aliphatic or aromatic amines and preferably alkanolamines, as well as mixtures of such. Useful amines may be represented by the formulae: 2C0S19 wherein R is hydrogen, an alkyl, alkanol, alkaryl or aryl 2 . 3 radical; R is hydrogen, alkyl or alkanol radical; R is hydro- 4 gen, hydroxyl, alkyl, alkanol,or aryl radical; R N is pyrrolidi inyl, pyrrolinyl, pyrrolyl, morpholinyl, piperidinyl.or piperazrr: 5 inyl radical and R is hydrogen, alkyl, or alkanol radical*. The term "aryl" as used herein is intended to refer to a phenyl or naphthyl radical. One or more of the hydrogen atoms on the aryl radical may be replaced by a substituent group such as a nitro; halogen, preferably chlorine; alkyl, preferably a 1 to 5 carbon group, more preferably methyl; aryl; amino or/alkoxy, preferably a 1 to 5 carbon alkoxy group. In addition, pyridazine, pyrimidine and pyridine and such compounds wherein one or more hydrogen atoms are replaced with hydrogen, hydroxy or alkyl radicals are also useful in preparing additives witjh^.n the scope of the present invention. The::terms pyrrolyl, pyrrolidiriyl, morphol-inyl and piperidinyl, as used herein are intended to include the substituted radicals which are known to the art, e.g., N-methyl-morpholine, and 4-(2-aminoethoxy) ethylmorpholine. A particularly; preferred amine component ...for reacting with the aromatic group-containing carboxylic acid to produce the additives of the invention is a residue product derived from commercial processes to produce alkanolamines such as that described in the U.S. Patent No. 3,329,517 to Dodson. The additive is derived from the residue obtained in preparing ethanolamines. The residue.product may be derived from a number of well known methods which are employed to synthesize ethanolamines. It may be obtained from such reactions as the ammonolysis or amination of ethylene oxide, the reduction of nitro alcohols, the reduction of amino aldehydes, ketones and esters, and the reaction of halohydrins with ammonia or amines. The exact composition of the residue product varies within certain limits, and,.therefore, the term "ethanolamines";.as used herein and in the claims refers to one or more mono-, di-, or triethanolamines, preferably between 40 to 85% by volume triethanolamine. In general the residue product is predominantly triethanolamine. A specific residue product which is employed in a particularly preferred embodiment of this invention is a mixture of mono-, di-, and trieth-a^nolamine which is available commercially and has the followifrOfj chemical if ^ and physical properties: A\ ~ ' i* W J-\ 2 0031 9 qo Triethanolamine 45 to 55% by volume Equivalent weight 129 to 139 Tertiary amine.; 6.2 to 7.0 meq./gm. Water 0.5% by wgt., maximum v ■ Density 9.49 lbs./gal The aromatic group-containing carboxylic acids reacted with the amines herein include mono- and polycarboxylic acids having one or more aromatic groups in their molecular structure. The terms "aromatic" and "aryl" as employed herein include the unsaturated cyclic hydrocarbon radicals principally, as exemli-fied by the phenyl, benzyl, naphthyl, etc., radicals. Such carboxylic acids could have groups (e.g. alkyl-, halo-, nitro-, hydroxy, etc., groups) in addition to, for example located upon, such aromatic or aryl groups so long as such do not deleteriously affect the intended use of the additive compound according to the irivention. Illustrative of the aromatic group-containing carboxylic acids useable herein are aromatic carboxylic acids such as benzoic acid, phthalic acid and the alkyl benzene carboxylic 20 acids. Also, aryl-substituted aliphatic acids such as naphth- aleneacetic acid and mandelic acid ( cl -hydroxyphenylacetic acid). Mixtures of such acids may also be used. Moreover, anhydrides of such acids may be used herein but it may be necessary to first convert the anhydride to the acid prior to reaction with the amine component. A particularly preferred carboxylic acid component for reaction with the amines to produce the additives according to the invention is that obtained from a by-product in commercial processes to produce phthalic anhydride by the oxidation of naphthalene, typically in the presence of catalyst, to phthalic anhydride. In the final stages of such processes, the oxidation product is subjected to a distillation step towards recovery of the highly pure anhydride product. A by-product produced from such distillation, sometimes referred to in the industry as "phthalic lites," comprises a mixture of benzoic acid and phthalic anhydride. This by-product because of its impurity has limited usage. Also, its toxicity makes its disposal complicated. It has been found that such by-product, after treatment to con-39 vert the phthalic anhydride to the acid, is an ideal material 30 2C0319 to react with amine to produce the grinding aid additive of the invention. The by-product is economically available, and its use in hydraulic cement wherein it is ultimately encased (in concretes, etc.), is an enviromentally desirable disposal. Moreover, the * by-product is obtained from a feedstock, naphthalene, obtainable from coal tar, and thus many of the problems associated with chemicals solely dependent upon petroleum for their availability are avoided. The "phthalic lites" by-product mixture as aforedescribed is principally comprised of a mixture of benzoic acid and phthalic anhydride. The exact proportions of each of such ingredients in the mixture can vary widely, say from 99:1 to 1 Benzoic acid to anhydride. It has been found desirable to convert the anhy-. dride in the by-product to the acid prior to reaction with the amine to produce the grinding aid of the invention. If the product is not so converted, esters are produced in the reaction with the amine, which leads to products which are less effecitive as grinding aids. The preferred method for conversion of the "phthalic lites" by-product mixture is by hydrolysis, hereinafter termed "hydrolyzed phthalic lites". In the preferred procedure, the byproduct mixture is heated to a molten condition (e.g. 110°C.) which renders it easily transportable, pumpable, etc., and added to hot water (e.g. about 80°C) to effect the conversion of the anhydride to phthalic acid. After cooling, the amine reactant is added to produce essentially a mixture of amine salt of benzoic acid cind amine salt of phthalic acid. The amine salt additive of the invention is interground with the cement in the grinding mill to provide increased grinding efficiency as well as other advantageous results, e.g., inhibiting pack-set of bulk stored cement. The additives of the invention are particularly preferred for use with Portland cement, a class of hydraulic cement comprised essentially of two calcium silicates and a lesser amount of calcium aluminate. These cements are produced by heating an intimate mixture of finely divided calcareous material (limestone) and argillaceous material (clay) to form a clinker. The clinker is ground with the addition of aboui\.2'per- if*** cent gypsum, or some other form of calcium sulfate, to obtain the desired setting qualities in the finished cement. &t isVjf©,^ 200319 the clinker that the additive of the invention is preferably added to increase grinding efficiency and to inhibit subsequent pack-set in the finished cement. The additives of the present invention may be employed in either dry or liquid form. For convenience, the additive is in water solution to permit accurate metering into the mill stream. The addition is accomplished either prior to the grinding or the additive is introduced into the grinding mill simultaneously with the cement. If the additive is employed merely for the reduction of pack-set or for fluidizing purposes, it is added at any convenient point in the processing. The additive of the invention is employed effectively over a relatively wide range. The preferred range is about 0.001 to 1 percent based on the weight of the cement i.e., the weight of additive solids based on the weight of the cement solids (herein referred to as "solids on solids"). In a particularly preferred embodiment, the amount of additive employed is about 0.004 to 0.04 percent. Higher levels are employed if grinding to a relatively high surface area, and the amount of additive is limited solely by the desired surface area and the degree of fluidity desired. As used herein, the term "pack-set" is intended to refer to the agglomeration or adhesion of particles by, for example, storing or transporting in bulk. Adhesion results from surface forces, the majority of which are believed to be created during the grinding of the cement. Pack-set is determined in the following manner: One hundred grams of the cement is placed in a 250 milliliter Erhlenmeyer flask set on top of a variable vibrator. The flask containing the cement is vibrated 15 seconds after which it is removed from the vibrator and set into a jig with the axis of the flask lying horizontally. The flask is then rotated around its axis until the cement which is compacted in the bottom of the flask collapses. The flask is twisted at 180° angles at approximately 100 twists per minute. The number of 180° twists required for the sample to collapse establishes the pack-set. Thus, the * greater the energy required to break up the bed, the higher will be the pack-set. The following examples will serve to further illustrate JM -7- 2 0031 9 the invention. EXAMPLE I In experiments testing the effectiveness of chemicals as grinding aids for Portland cement, several aromatic acid components were first reacted with a triethanolamine mixture to form a salt thereof, and test grinds made in a laboratory batch mill. The triethanolamine mixture was a product obtained as a residue product of ethanolamine synthesis previously described. Several clinkers ("A" through "D" in Table I), each from a different manufacturing source, were used in the tests. In the tests, 3325 grams of clinker (-20 mesh size) were ground along with 175 grams of gypsum (the latter is used in commercial production of "Portland cement''). The amine salts were added in various proportions (salt solids on cement solids) to the clin-ker-gypsum mixture before grinding. For comparison, a "blank" control grind, that is, a grind of each of the clinkers "A" through "D" with gypsum and no grinding aid was also performed. Each grind with respect to a single clinker was ..identical, that is, the mill was operated the same number of revolutions at 220°F, and the surface area ("Blaine Surface Area") of the resulting ground product measured in centimeters square per gram. The exact number of revolutions varied between 5000 and 10,000 depending upon the particular clinker. The increase in fineness (the increase in "Blaine Surface Area") evidenced by the ground test samples containing grinding aid was calculated as a percent of the surface area measured for the "blank" control. This percentage is recorded as "Percent Improvement Over Blank" in Table I. Duplicate, and in some cases triplicate, grinds were made of the grinding aids tested and the "Percent Improvement Over Blank" shown in Table I is an average value thereof. In Table I, the "Hydrolyzed Phthalic Lites" product was obtained as previously generally described, using in particular the "Procedure No. 1" of EXAMPLE II. For further comparison, additional test grinds were made using a commercial grinding aid. The results are reported in Table I. JM -8- 2 1 9 TABLE I Percent Improvement Over Blank * Addition Rate. Run . Run Run Clinker Grinding Aid (% sos) 11 ' #2 #3 Average A Triethanolamine Salt of Phthalic Acid 0. 025 6 .7 8. 6 7 .3 7. 5 A Triethanolamine Salt of Phthalic Acid 0. 014 3 .5 1. 8 — 2. 7 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 Triethanolamine Salt of Naphthalaneacetic Acid 0. 025 5 .7 7. 3 6. 5 A Triethanolamine Salt Benzoic Acid 0. 025 6 .9 8. 5 — 7. 7 A Triethanolamine Salt of Hydrolyzed Phathalic Lites 0. 015 3 .1 6. 0 6 .5 5. 2 A Commercial Product 0. 015 6 .3 6. 3 8 .1 6. 9 B Triethanolamine Salt of Hydrolyzed Phthalic Lites 0. 015 8 .9 9. 3 8 .9 9. 0 B Commercial Product 0. 015 5 .8 8. 3 10 .7 8. 3 C Triethanolamine Salt of Hydrolyzed Phthalic Lites 0. 015 6 .1 5. 0 8 .7 6. 6 C Commercial Product 0. 015 7 .8 5. S 7 .0 6. 9 D Triethanolamine Salt of Hydrolyzed Phthalic Lites 0. 015 8 .2 8. 5 7 .1 7. 9 D Commercial Product 0. 015 6 .4 7. 7 8 .6 7. 6 A Triethanolamine Salt of Naphthalene Sulfonic Acid 0. 025 4 .9 6. 4 — 5. 7 EXAMPLE II Two procedures may be used in the preparation of the triethanolamine salt from "hydrolyzed phthalic lites", the method of choice being dictated primarily by the type of processing equipment available. The figures given in this exam- JM -9- 2 003 1 pie are based upon a 1000 gram batch although in practice batches as large as 500 lbs. have been prepared using both procedures . Procedure: #1 v - Step 1: Melt 292 grams of phthalic lites and heat molten material to between 110° and 115°C. Step 2: Add 20 grams of hot water (93° - 100°C) to the molten phthalic lites with vigorous stirring. Step 3: Monitor the temperature of the reaction mixture. Initially it will climb as the exothermic, hydrolysis reaction takes place, then become constant as thermal equilibrium is reached and finally fall after the hydrolysis step reaches completion. Step 4: Upon completion of the hydrolysis (as indicated by the decrease in reaction mixture temperature) add 448 grams of triethanolamine with moderate stirring. Step 5: When the reaction mixture temperature falls to below 90°C. add 24 0 grams of water. Procedure #2 Step 1.: Heat 260 grams of water to between 75° and 100°C. Step 2: Add 292 grams of molten phthalic lites to the hot water with vigorous stirring. The temperature of the molten material should be between 110° and 115°C. Step 3: Monitor the temperature of the reaction mixture as in Step 3 of Procedure #1. Step 4: When the temperature of the reaction mixture falls to 70°C begin a slow addition of 448 grams of triethanolamine with moderate agitation. The rate of triethanolamine addition should be adjusted so that the temperature of the reaction mixture does not exceed 100°C. EXAMPLE III The ability of the grinding aid of the invention to also act as inhibitors of the "pack-set" of the ground product was tested. Table II shows the result of tests as described previously for ability to inhibit the "pack-set" tendencies of Portland cement clinker mixtures "A", "B", and "D". The lower the "Pack-Set" number, the more effective the grinding aid is JM -10- </div>

Claims

<div class="application article clearfix printTableText" id="claims"> 2 003 19 as an inhibitor of "pack-set". TABLE II Cement Addition Clinker ... Grinding Aid . Rate (% sos) . Pack Set A None (blank) - 30 A Triethanolamine Salt of 0.025 5 Naphthaleneacetic Acid 0 A Triethanolamine Salt of 0 .025.' 2 Benzoic Acid A Triethanolamine Salt of 0.025 3 Phthalic Acid A Commercial Product 0.025 5 A Commercial Product 0.015 9 A Triethanolamine Saltof 0.015 7 "Hydrolyzed Phthalic Lites" B None (blank) - 14 B Triethanolamine Salt of 0.015 9 "Hydrolyzed Phthalic Lites" B Commercial Product 0.015 14 20 D None (blank) - 29 D Triethanolamine Salt of 0.015 11 "Hydrolyzed Phthalic Lites" D Commercial Product 0.015 8 30 39 -rmr _11_ 2G0S19 WHAT WE CLAIM IS:-

1. A hydraulic cement composition comprising hydraulic cement and a small amount of an amine salt of an aromatic group-containing carboxylic acid.

2. The composition of claim'1 wherein said cement is Portland cement.

3. The composition of claim 1 or 2 wherein" saidr.amine is an alkanolamine or mixture thereof.

4. The composition of claim 1 or 2 wherein said acid is an aromatic mono- or dicarboxylic acid containing a benzene or napthalono nucleus, or an aryl-substituted aliphatic acid.

5. The composition of claim 1 or 2 wherein said acid is benzoic acid, phthalic acid, naphthalene-acetic acid, or mixture of such.

6. A Portland cement composition comprising Portland cement and, intimately mixed therewith, from 0.001 to 1 percent by weight of an amine salt of an aromatic group-containing carboxylic acid, said carboxylic acid being a mixture of aromatic carboxylic acids obtained from a by-product produced in a process for producing phthalic anhydride.

7. The composition of claim 6 wherein said mixture of acids comprises a mixture of benzoic and phthalic acids.

8. The composition of claim 6 or 7 wherein said mixture of acids is produced by hydrolysis of a by-product mixture containing benzoic acid and phthalic anhydride.

9.* The composition of claim 6 or 7 wherein said byproduct is obtained as a result of distilling an oxidation product obtained, in a process to produce phthalic anhydride by the oxidation of naphthalene.

10. The composition of claim 6 or 7 wherein said amine comprises triethanolamine or a,mixture of such with other amines.

11. The composition of claim 6 or 7 wherein such amine comprises a residue product of ethanolamine synthesis.

12. The method which comprises grinding a hydraulic cement in the presence of an amine salt of an aromatic group-containing carboxylic acid,

13. The method of claim 12 wherein said cement is>;^Vtl^niP\! cement. , o\

14. The method of claim 12 or 13 wherein said am'tne1

^ Vk!":

2C0S19

alkanolamine or mixture of amines containing alkanolamine.

15. The method of claim 12 or 13 wherein said acid is benzoic acid, phthalic acid, naphthalene acetic acid, or mixture of such.

16. The method of claim 12 or 13 wherein said acid comprises a mixture of acids obtained from a by-product from a process to produce phthalic anhydride.

17. A hydraulic cement composition as claimed in claim 1 substantially as specifically described herein in any one of the Examples.

18. A method of producing a hydraulic cement composition as claimed in claim 12, substantially as specifically described herein in any one of the Examples.

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