GB2106482A - Method for retarding gelation of bicarbonate-carbonate-zeolite- silicate crutcher slurries - Google Patents

Abstract

Gelation and setting of desirably miscible and pumpable crutcher slurries comprising sodium carbonate, sodium bicarbonate, zeolite and sodium silicate in an aqueous medium are retarded and often prevented by the addition to such medium of a citric material, such as citric acid and/or water soluble citrate, and magnesium sulphate. Alternatively, magnesium citrate may be employed.

Description

SPECIFICATION Method for retarding gelation of bicarbonate-carbonate-zeolite-silicate crutcher slurries The present invention relates to non-gelling aqueous slurries of inorganic salt mixtures and to methods for their manufacture. More particularly, it relates to the utilization of certain materials which, in combination, develop an exceptionally good and improved anti-gelling action, preventing gelation, excess thickening and setting up of bicarbonate -- carbonate -- zeolite -- silicate slurries from which particulate heavy dury synthetic organic detergent compositions may be made, as by spray drying such slurries and post-spraying the resulting dried beads with a synthetic nonionic detergent.

Aqueous crutcher mixes containing substantial proportions of bicarbonate, carbonate, zeolite and silicate tend to gel or set prematurely, sometimes before they can be thoroughly mixed and pumped out of a crutcher to spray towers. Consequently, extensive experimentation has been undertaken in an effort to find ways to diminish the tendencies of such systems to solidify or gel in the crutcher. Citric acid or water soluble citrates incorporated in the crutcher mix delays or prevents gelation and setting of bicarbonate -- carbonate -- silicate mixes and allows commercial spray drying thereof, following normal procedures for pumping out the crutcher contents to the spray nozzles. However, while such a process was and is successful, it has been supplanted by the present process when zeolite is present in the crutcher and the anti-gelling effect obtained is greater.In addition to improving the anti-gelling activity and increasing the length of time in which a crutcher mix would be workable without the need for significantly larger proportions of anti-gelling agent being incorporated, the present invention allows the use of a lesser proportion of organic material, thereby decreasing the likelihood of the spray dried composition deteriorating in the heat of the dryer, and improving the absorbency and flowability of the product. Also, whereas the citric acid component, if used in larger quantity, could interfere with the absorption of liquid nonionic detergent sprayed onto such spray dried base beads, magnesium sulphate appears to be desirably absorbent, thereby helping to make the product free flowing.

In the aqueous crutcher mix the various dissolved anti-gelling compounds can ionize and therefore it may be considered that in the crutcher mix there are present magnesium, citrate and sulphate ions.

Accordingly, crutcher mixes having charged thereto mixtures of compounds that result in the desired ionic composition are also useful for retarding and preventing gelation of inorganic crutcher mixes. Thus, magnesium citrate or magnesium acid citrate can be employed in the present invention, preferably with sodium sulphate, but also without the sulphate being present, because it is considered that the magnesium and citrate ions are the most effective in inhibiting gelation. Citric acid and the various citrates may be referred to herein as "citric material".

In accordance with the present invention, a miscible and pumpable crutcher slurry which does not prematurely gel or set and which is capable of being mixed and pumped for a period of at least an hour after mixing, comprises from 40 to 70% of solids and 60 to 30% of water, of which solids content, on a 100% solids basis, about 20 to 45% is sodium bicarbonate, about 10 to 30% is sodium carbonate, about 5 to 25% is sodium silicate of Na20:SiO2 ratio within the range of 1:1.4 to 1:3, and about 10 to 65% is zeolite, with the ratio of sodium bicarbonate: sodium carbonate being within the range of about 1:1 to 4:1, the ratio of sodium carbonate: sodium silicate being within the range of about 1:2.5 to 5 :1, the ratio of sodium bicarbonate: sodium silicate being within the range of about 1:1 to 8:1, and the ratio of zeolite: silicate being within the range of about 1:2 to 10 :1, and which solids content includes, on a slurry basis, a gelation retarding proportion of a combination of 0.1 to 2% of a citric material comprising citric acid, one or morewater soluble citrates or mixtures thereof, and from 0.1 to 1.4% of magnesium sulphate, with the total of such citric material and magnesium sulphate being at least 0.4% of the slurry.

The invention also relates to a method for retarding or preventing the gelation of a miscible and pumpable crutcher slurry of the general bicarbonate -- carbonate -- zeolite -- silicate type described, by addition thereto of a citric material and magnesium sulphate, in the described small quantities. The invention is also of similar slurries and methods wherein magnesium citrate is present or is utilized as an anti-gelling material.

Although the anti-gelling features of the present invention may also be obtained with other inorganic builder base compositions than those which are primarily of bicarbonate, carbonate, zeolite, silicate and water, such as those not including the zeolite, very significant anti-gelling effects are noted when the zeolite-containing crutcher mixes are treated by the method of this invention, i.e., addition of citric material and magnesium sulphate (or magnesium citrate). It is significant that the zeolite, although hydrated, does not tend to dissolve in the crutcher, and consequently, its presence can cause significant thickening of the mix. Also, the finely divided zeolite particles can serve as nuclei for gel formation and for precipitation.

The slurries or crutcher mixes treated in accordance with this invention preferably comprise 40 to 70% of solids and 60 to 30% of water. The solids content, on a 100% solids basis, is preferably 20 to 45% of sodium bicarbonate, 10 to 30% of sodium carbonate, 10 to 65% of zeolite and 5 to 25% of sodium silicate, preferably of Na2O :SiO2 ratio within the range of 1:1.4 to 1:3.In such compositions the ratio of sodium bicarbonate :sodium carbonate is preferably within the range of 1 or 1.2:1 to 4:1, the ratio of sodium carbonate:sodium silicate is preferably within the range of 1:2.5 to 5:1, the ratio of sodium bicarbonate :sodium silicate is preferably within the range of 1:1 to 8:1 and the ratio of zeolite:silicate is preferably within the range of 1:2 to 10:1. The percentage of citric material, namely citric acid, water soluble citrate, a mixture of such citrates or a mixture of citric acid and such citrate or citrates, is preferably from 0.1 to 2% and the percentage of magnesium sulphate is preferably from 0.1 to 1.4%, on a slurry basis.The total of citric material and magnesium sulphate is preferably at least 0.4% and will usually not exceed 2.5 to 3%, with the percentages mentioned being on a total crutcher mix or slurry basis, such slurry including the mentioned salts, water and any adjuvants which may be present.

A preferred range of such total is 0.5 to 3%, more preferably 0.6 to 2% and most preferably, usually, 1 To 2%. Although the employment of a combination of citric material, such as citric acid, and magnesium sulphate is preferable, there may be used in substitution for it from 0.3 to 3%, preferably 0.5 to 2%, of magnesium acid citrate (MgHC6HsO7.5H20) or equivalent proportion of equivalent magnesium citrate.

Preferably, the crutcher slurry contains from 50 to 65% of solids, with the balance being water, and of the solids content, 25 to 40% is sodium bicarbonate, 13 to 25% is sodium carbonate, 5 to 25% is sodium silicate of Na20 :SiO2 ratio within the range of 1:1.6 to 1:2.6, and 35 to 65% is hydrated, water softening zeolite, with the ratio of sodium bicarbonate sodium carbonate being within the range of 1.5:1 to 3:1, the ratio of sodium carbonate sodium silicate being within the range of 1:2 to 2:1, the ratio of sodium bicarbonate :sodium silicate being within the range of 2:1 to 5:1, and the ratio of hydrated, water softening zeolite:sodium silicate being within the range of 2:1 to 7::1, the percentages of citric material and magnesium sulphate being 0.1 to 0.8 and 0.1 to 1.2, respectively, with a minimum total of 0.4%. More preferably, the crutcher slurry contains from 55 to 65% of solids and 45 to 35% of water, of which solids content 25 to 35% is sodium bicarbonate, 13 to 20% is sodium carbonate, 8 to 15% is sodium silicate of NazO: sio2 ratio in the range of 1:2 to 1:2.4, and 35 to 50% is hydrated, water softening zeolite.In such more preferred compositions the ratio of sodium bicarbonate :sodium carbonate is within the range of 1.5:1 to 2.5:1, the ratio of sodium carbonate sodium silicate is within the range of 1:1 to 2:1, the ratio of sodium bicarbonate :sodium silicate is within the range of 2:1 to 4:1, and the ratio of hydrated, water softening zeolite: sodium silicate is within the range of 3:1 to 5:1.

In such cases the percentages of gelation preventing citric material and magnesium sulphate are in the ranges of 0.2 to 0.6% and 0.4 to 1.1%, respectively. The materials described herein, except for water, are all normally solid and the percentages and ratios are on an anhydrous basis, although the various materials may be added to the crutcher as hydrates, or dissolved or dispersed in water. Normally, however, the sodium bicarbonate is anhydrous and the sodium carbonate is soda ash. However, the carbonate hydrate(s), such as the monohydrate, may also be employed.The silicate is usually added to the crutcher slurry as an aqueous solution, normally of 40 to 50% solids content, e.g., 47.5%, and is preferably added near the end of the mixing process and after previous additions and dispersions and dissolutions of the citric material and magnesium sulphate (or magnesium citrate). The silicate employed will usually be of Na20 :SiO2 ratio within the range of 1:1.6 to 1:2.6, preferably 1:1.6 to 1:2.4 and more preferably 1:2 to 1:2.4.

The zeolites employed include crystalline, amorphous and mixed crystalline-amorphous zeolites of both natural and synthetic origins which are of satisfactorily quick and sufficiently effective activities in counteracting calcium hardness ions in wash waters. Preferably, such materials are capable of reacting sufficiently rapidly with the calcium ions so that, alone or in conjunction with other water softening compounds in the detergent, they soften the wash water before adverse reactions of such ions with other components of the synthetic organic detergent composition occur. The zeolites employed may be characterised as having a high exchange capacity for calcium ion, which is normally from about 200 to 400 or more milligram equivalents of calcium carbonate hardness per gram of the aluminosilicate, preferably 250 to 350 mg. eq./g.Also they preferably have a hardness depletion rate residual hardness of 0.02 to 0.05 mg. CaCO, /litre in one minute, preferably 0.02 to 0.03 mg./l., and less than 0.01 mg./l.

in 10 minutes, all on an anhydrous zeolite basis.

Although other ion exchanging zeolites may also be utilized, normally the finely divided synthetic zeolite builder particles employed in the practice of this invention will be of the formula (Na2O)x. (Al203)y. (SiO,),. H20 wherein x is 1 , y is from 0.8 to 1.2, preferably about 1, z is from 1.5 to 3.5, preferably 2 to 3 or about 2 and w is from 0 to 9, preferably 2.5 to 6.

The zeolite should be a univalent cation-exchanging zeolite, i.e., it should be an aluminosilicate of a univalent cation such as sodium, potassium, lithium (when practicable) or other alkali metal, ammonium or hydrogen (sometimes). Preferably the univalent cation of the zeolite molecular sieve is an alkali metal cation, especially sodium or potassium, and most preferably is sodium.

Crystalline types of zeolites utilizable as good ion exchangers in the invention, at least in part.

include zeolites of the following crystal structure grounds: A, X, Y, L, mordenite and erionite, of which types A, X and Y are preferred. Mixtures of such molt ,1ar sieve zeolites can also be useful, especially when type A zeolite is present. These crystalline types of zeolites are well known in the art and are more particularly described in the text Zeolite Molecular Sieves by Donald W. Breck, published in 1974 by John Wiley 8 Sons. Typical commercially available zeolites of the aforementioned structural types are listed in Table 9.6 at pages 747-749 of the Breck text, which table is incorporated herein by reference.

Materials listed therein include Type A; Linde Type 3A, 4A and 5A all obtainable as powders of particle size less than 10 microns, Davison Type 3A, 4A and 5A all obtainable as powders of particle size 3 to 5 microns; Type X; Linde Type 10X, and 1 3X obtainable as powders of particle size less than 10 microns; Davison Type 1 3X obtainable as a powder of particle size 3 to 5 microns; Type Y; Linde SK 41 as a powder of 1 to 2 micron particle size; Type L; Linde SK 45 as a powder of 5 to 10 micron particle size; and Mordenite; as Norton Zeolon-1 00 (Na or H form) as a powder of particle size 5 to 12 microns.

Also, suitable zeolites have been described in many patents in recent years for use as detergent composition builders.

The zeolite used in the invention is usually synthetic and it is often characterised by having a network of substantially uniformly sized pores in the range of about 3 to 10 Angstroms, often being about 4 A (normal), such size being uniquely determined by the unit structure of the zeolite crystal.

Preferably it is of type A or similar structure, particularly described at page 1 33 of the aforementioned text. Good results have been obtained when a Type 4A molecular sieve zeolite is employed, wherein the univalent cation of the zeolite is sodium and the pore size of the zeolite is about 4 Angstroms. Such zeolite molecular sieves are described in U.S. Patent 2,882,243, which refers to them as Zeolite A.

Molecular sieve zeolites can be prepared in either a dehydrated or calcined form which contains from about 0 or about 1.5% to about 3% of moisture or in a hydrated or water loaded form which contains additional bound water in an amount from about 4% up to about 36% of the zeolite total weight, depending on the type of zeolite used. The water-containing hydrated form of the molecular sieve zeolite (preferably about 1 5 to 70% hydrated) is preferred in the practice of this invention when such crystalline product is used. The manufacture of such crystals is well known in the art.For example, in the preparation of Zeolite A, referred to above, the hydrated zeolite crystals that are formed in the crystallization medium (such as a hydrous amorphous sodium aluminosilicate gel) are used without the high temperature dehydration (calcining to 3% or less water content) that is normally practiced in preparing such crystals for use as catalysts, e.g., cracking catalysts. The crystalline zeolite, in either completely hydrated or partially hydrated form, can be recovered by filtering off the crystals from the crystallization medium and drying them in air at ambient temperature so that their water contents are in the range of about 5 to 30% moisture, preferably about 10 to 25%, such as 1 7 to 22%.However, the moisture content of the molecular sieve zeolite being employed may be much lower, as was previously described, in which case the zeolite will usually become hydrated during crutching and other processing.

Preferably the zeolite should be in a finely divided state with the ultimate particle diameters being up to 20 microns, e.g., 0.005 or 0.01 to 20 microns, preferably being from 0.01 to 15 microns and especially preferably of 0.01 to 8 microns mean particle size, e.g., 3 to 7 or 12 microns, if crystalline, and 0.01 to 0.1 micron, e.g., 0.01 to 0.05 micron, if amorphous. Although the ultimate particle sizes are much lower, usually the zeolite particles will be of sizes within the range of 100 to 400 mesh, preferably 140 to 325 mesh (these being U.S. mesh sizes -- U.S. 100 mesh has openings of 149 microns, 140 mesh of 105 microns, 325 mesh of 44 microns and 400 mesh of 37 microns).Zeolites of smaller sizes will often become objectionably dusty and those of larger sizes may not sufficiently and satisfactorily cover the carbonate-bicarbonate base particles.

It is highly preferred to make the crutcher slurry and the base bead product of this invention (from which a heavy duty built nonionic synthetic organic detergent composition can be produced) of essentially inorganic salts, some water soluble and some water insoluble, in such manner that they will be of bead properties that promote absorption through the bead surfaces of nonionic detergent sprayed thereon in liquid form. Therefore, adjuvants, such as perfumes, colorants, enzymes, bleaches and flow promoting agents, are often sprayed onto the beads with the nonionic detergent or are post-added, so that their presence in spray dried beads does not inhibit absorption of the detergent. However, for stable and normally solid adjuvants, mixing in with the inorganic salt slurry in the crutcher can also be feasible.

Thus, it is contemplated that from 0 to as much as 20% of the crutcher slurry may be of suitable adjuvants or diluents (diluents include inorganic salts, such as sodium sulphate and sodium chloride).

However, if such adjuvants are present, normally the proportion thereof will be from 0.1 to 10% and often their content will be limited to 5%, and sometimes to 1 or 2%. Normally the organic material content of the crutcher slurry will be limited to about 5% maximum, so as to avoid any problems of tackiness of the base beads after spray drying and to avoid any adverse effects on absorption of synthetic nonionic organic detergent by the beads. Because magnesium sulphate is inorganic and appears to be useful in aiding absorption of nonionic detergent by the base beads and because it improves the anti-gelling activity of the citric material it allows the use of less citric material and thereby promotes the production of a more desirable base bead, lower in organic content.

The preferred combination of gelation preventing materials employed, which have been found to be startlingly successful in preventing gelation, thickening, setting and freezing up of the crutcher slurry before it can be emptied from the crutcher and spray dried, using normal crutching, pumping and spray drying equipment, are citric material and magnesium sulphate. Because the crutcher slurry, including both dissolved and dispersed inorganic salts, is normally alkaline, usually being of a pH in the range of 9 to 12, preferably 10 to 11, when the citric material employed is citric acid it is considered to be ionized and converted to the corresponding citrate or brought into equilibrium with citrate ions.Thus, other soluble citrates may be employed instead of citric acid, including sodium citrate, potassium citrate and magnesium citrate, although for many applications the acid is considered to be superior. Instead of adding citrate, a mixture of the acid and a neutralizing agent, e.g., NaOH, KOH, or Mg(OH)2, may be used, and instead of the acid form, a citrate plus an acid can be substituted, if desired (although this latter course of action will rarely be followed). The proportion of citric material, in combination with magnesium sulphate, will normally be only sufficient to accomplish the gelation preventing task in the particular crutcher slurry to be treated. However, for safety's sake an excess, e.g., 5 to 20% more than the sufficient quantities of citric material and magnesium sulphate, may be employed.While it is possible to use as much as 3.4% of the combination of citric material and magnesium sulphate, on a crutcher contents weight basis, to retard or prevent gelation, usually from 0.4 to 2.5% will suffice, preferably from 0.5 to 2%. When employing a citrate, such as an alkali metal citrate, one may wish to increase the percentage of the additive slightly to compensate for the presence of the heavier cation but for simplicity's sake the range of proportions of additives given will apply to both the acid and salt forms.

With respect to the magnesium compounds, the sulphate is highly preferred but this may be replaced by other sources of magnesium as by the magnesium ion in magnesium citrate, when that compound is used, usually in proportion from 0.3 to 3%, preferably 0.5 to 2%, on a slurry basis.

The order of addition of the various components to the crutcher is not considered to be critical, except that it is highly desirable to add the silicate solution last, and if not last, at least after the addition of the gel preventive combination of materials. Also, minor variations in orders of addition may be made under certain circumstances, as when objectionable foaming accompanies the following of a specific order. However, such problems have not been found to be serious. In some instances it is possible to premix the magnesium sulphate and citric material and to add the mixture thereof to the crutcher. In other cases the citric material is added first, followed by the magnesium sulphate, or vice versa. If desired, one or both of the citric material and magnesium sulphate may be premixed with another material or with other materials.In such instances it will be preferred for the anti-gelling additive components to be mixed in with other crutcher mix materials before addition of the silicate to the crutcher. However, in some instances one can add the anti-gelling materials after addition of the silicate, but preferably very promptly thereafter.

Preferably, for the manufacture of the crutcher mix, water will be added to the crutcher initially, followed by magnesium sulphate, part of the citric material, part of the zeolite, bicarbonate, carbonate, the balance of the citric material, the balance of the zeolite, part of the silicate, and the balance of the silicate. Normally, mixer speed and power will be increased as the materials are added. For example, low speeds may be used until after admixing in of the last of the zeolite, when the speed may be increased to medium, and then to high before addition of the second portion of silicate solution. Dispersion or solutions of the individual components may be made beforehand, if feasible. The water employed may be city water of ordinary hardness.In theory, it is preferable to utilize deionized water or distilled water, if available, because some metallic impurities in the water may have a triggering action on gel formation, but that is not considered to be necessary.

The temperature of the aqueous medium in the crutcher will usually be at about room temperature or elevated, normally in the 20 to 700C range and preferably will often be from 25 to 400 C. Heating the crutcher medium may promote dissolution of the water soluble salts of the mix and thereby increase the mobility of the mix. However, the heating operation can slow production rates and therefore an advantage of the present invention is that non-gelling slurries are obtainable at lower temperatures.

Temperatures higher than 70"C will usually be avoided because of the possibility of decomposition of one or more crutcher mix components, e.g., sodium bicarbonate. Also, in some cases lower crutcher temperatures increase the upper limits of crutcher solids contents, probably due to insolubilizing normally gelling components.

Crutcher mixing times to obtain good slurries can vary widely, from as little as ten minutes for small crutchers and for slurries of higher moisture contents, to as much as four hours, in some cases.

The mixing times needed to bring all the crutcher mix components together in one medium may be as little as five minutes but in some cases, can take up to an hour, although 30 minutes is a preferable upper limit. Counting any such initial admixing times, normal crutching periods will be from 1 5 minutes to two hours, e.g. 20 minutes to one hour, but the crutcher mix will be such as to be mobile, not gelled or set, for at least one hour, preferably for two hours, and more preferably for four hours or so after completion of the making of the mix, e.g. 10 to 30 hours (before pump-out to the spray tower).

The crutched slurry, with the various salts and any other components thereof, dissolved or in particulate form, uniformly distributed therein, in part due to the desirable anti-gelling effects of the citric compound and the magnesium sulphate, is transferred in usual manner to a spray drying tower, which is located near the crutcher. The slurry is normally dropped from the bottom of the crutcher to a positive displacement pump, which forces it at high pressure through spray nozzles at the top of a conventional spray tower (countercurrent or concurrent), wherein the droplets of the slurry fall through a hot drying gas, which is usually composed of fuel oil or natural gas combustion products, in which the droplets are dried to desired absorptive bead form. During the drying, part of the bicarbonate may be converted to carbonate, with the release of carbon dioxide, which appears to improve the physical characteristics of the beads made so that they become more absorptive of liquids, such as liquid nonionic detergent, which may be post-sprayed onto them subsequently. However, the zeolite component of the base beads made also favours absorption of liquid so less decomposition of bicarbonate still results in a highly absorptive product.

After drying, the product is screened to desired size, e.g., 10 to 100 mesh, U.S. Standard Sieve Series (10 mesh has openings of 2.00 mm), and is ready for application of nonionic detergent spray thereto, with the beads being either in warm or cooled (to room temperature) condition. However, the nonionic detergent will usually be at an elevated temperature to assure that it will be liquid; yet, upon cooling to room temperature, desirably it will be a solid, often resembling a waxy solid. Even if at room temperature the detergent is somewhat tacky this characteristic does not make the final composition poorly flowing because the detergent penetrates to below the bead surface. The nonionic detergent, is preferably applied to the beads whilst they are tumbled, e.g. in known manner, as a spray or as droplets.

The nonionic detergent is preferably a condensation product of ethylene oxide and higher fatty alcohol, with the higher fatty alcohol being of 10 to 20 carbon atoms, preferably of 12 to 1 6 carbon atoms, and more preferably averaging 1 2 to 1 3 carbon atoms, and with the nonionic detergent containing from 3 to 20 ethylene oxide groups per mole, preferably from 5 to 12, more preferably 6 to 8. Instead of the ethylene oxide being condensed with higher fatty alcohol the lipophilic portion of the detergent may be aromatic, e.g., nonylphenyl, isoctylphenyl or similar alkylphenyls, obtainable from corresponding phenols. The proportion of nonionic detergent in the final product will usually be from 10 to 25%, such as from 20 to 25%.

Whereas when using citric acid alone as the anti-gelling agent, without the magnesium sulphate and without the zeolite, the liquid absorption rate of the base beads would be good, with some base bead compositions and nonionic detergents it could be difficcult to have more than 20% of the nonionic detergent sufficiently quickly and satisfactorily absorbed by the base beads. It has been found that the present anti-gelling treatment, applied to a zeolite containing formula and utilizing a mixture of citric material and magnesium sulphate, e.g., citric acid and magnesium sulphate, and often with less citric acid being used to produce the same workability of the crutcher mix, can result in beads of better absorption properties, in which, for example, as much as 22% or even 25% of nonionic detergent may be absorbed in a reasonable time, with the production of a free flowing product.

A preferred finished formulation made from the presently described base beads contains from 1 5 to 25%, preferably 20 to 25% of the nonionic detergent, e.g., Neodol (Registered Trade Mark) 23-6.5, made by Shell Chemical Company, 1 5 to 25% of sodium bicarbonate, 5 to 1 5% of sodium carbonate, 25 to 35% of zeolite, 5 to 15% of sodium silicate, e.g., of Na2O : SiO2 ratio of about 1:2.4, 1 to 3% of fluorescent brightener, 0.5 to 2% of proteolytic enzyme, sufficient bluing to colour the product and whiten the wash, as desired, 3 or 5 to 10% of moisture, 0.25 to 1.2% of citric material, preferably sodium citrate and 0.8 to 2% of magnesium sulphate.Instead of the mixture of citric material and magnesium sulphate there may be present from 0.3 to 3% of magnesium citrate, preferably 0.5 to 2%.

Optionally, sodium sulphate may be present, as a diluent, but the amounts thereof will normally be restricted to less than 20% preferably to less than 10%, and most preferably to less than 5%, if it is present at all. The base beads made, devoid of nonionic detergent and adjuvants, will preferably comprise from 20 to 35% of sodium bicarbonate, 10 to 20% of sodium carbonate, 30 to 45% of zeolite, 10 to 20% of sodium silicate, 0.3 to 2% of sodium citrate and 1 to 2% of magnesium sulphate (or 0.5 to 4% of magnesium citrate), 0 to 10% of adjuvant(s) and/or diluent(s) and 3 to 10% of moisture. In such products the proportion of the sodium bicarbonate in the sprayed beads will normally be within the range of 1.2 to 4 times that of the sodium carbonate, e.g., 1.5 to 3 times.

The highly beneficial result of incorporating the mentioned small percentages of citric compound and magnesium sulphate or magnesium citrate in the crutcher slurry in accordance with this invention is two-fold. Gelation and setting of the crutcher mix in the vessel before complete discharge thereof is prevented, and additionally, higher solids content crutcher slurries may be made. Thus, down times and cleanouts are reduced.Although many bicarbonate -- carbonate -- zeolite -- silicate mixtures desirably employed in crutcher mixes for making base beads for built particulate nonionic detergent compositions would normally gel and set up in the crutcher, with the present invention, at little expense and without any detrimental effects on the product, the desired proportions of such builder salts can be employed and variations in such proportions can be made, as desired, with much reduced fear of freezeups in the crutcher. Tests of the final product show no adverse effects due to the presence of the citric material and magnesium sulphate therein. In fact, some positive results, due to metal ion sequestration and improved absorption of nonionic detergent, can result.The presence of the citric material is thought to promote maintenance of the stability of perfumes and colours present and it may help to prevent development of malodors from deteriorations of other organic additives sometimes present, such as proteolytic enzymes and proteinaceous materials. The presence of the citric materials and the magnesium sulphate in the base beads also has the desirable effect of having the gelation preventing material present in any base beads or detergent beads being reworked, so that such material, if offspecification (as for being undersize or for being tower wall build-up), may be mixed with water and made into a more concentrated rework mix for subsequent blending back with the regular crutcher mix.

Such mixing with water is easier than would be the case were the anti-gelling composition not present in the base beads to prevent or retard gelation or excessive thickening.

The invention may be put into practice in various ways and a number of specific embodiments will be described to illustrate the invention with reference to the accompanying examples.

Unless otherwise indicated all temperatures are in OC and all parts are by weight in the examples and throughout the specification. Also, when weights and proportions of zeolite are given these are intended to be for the normal hydrate being used, because it is considered that the zeolite water of hydration does not leave the zeolite and does not become part of the aqueous solvent medium in the present crutching operations.

EXAMPLES 1 A, 1 B and 1 C A 10,000 pound (4536 kg) crutcher mix batch was made by mixing in water at a temperature of about 270C (800F), with low speed crutcher mixing, and sequentially adding, 216 parts of Epsom salts (magnesium sulphate heptahydrate), 25 parts of citric acid, 1,264 parts of Linde hydrated zeolite 4A (20% water of crystallization), 1 ,634 parts of sodium bicarbonate, 821 parts of soda ash, 25 more parts of citric acid and 1 ,264 more parts of the mentioned zeolite, after which the mixer speed was increased to medium and 814 parts of a 47.5% aqueous solution of sodium silicate (Na2O : SiO2 ratio of 1:2.4) were admixed, after which the agitator speed was increased to high, and after another 20 seconds an additional 814 parts of the silicate solution was mixed in.Mixing of the entire batch then continued for at least an hour (and in some cases for as many as four hours), during which time about 500 parts of water were lost. During the mixing time the crutcher slurry was continuously mobile and did not gel or cake.

EXAMPLE 1B Starting about five minutes after all the components of the crutcher mix were present, the slurry of Example 1 A was dropped from the crutcher to a pump which pumped it at a pressure of about 300 p.s.i.

(about 21 kg/sq. cm) into the top of a countercurrent spray tower wherein the initial temperature was about 8000F (430 C) and the final temperature was about 2200F (105"C). The essentially inorganic base beads resulting were of a bulk density of about 0.7 g/ml, an initial adhesion of about 40%, a particle size range substantially between 10 and 100 mesh, U.S. sieve series, and a fines characteristic (through U.S. Sieve No. 50 (U.S. mesh 50 has openings of 297 microns)) of about 15%. The moisture content of the product was about 7%. The base beads were found to be free flowing, non-tacky, porous, yet firm on the surfaces thereof, and capable of readily absorbing significant proportions of liquid nonionic detergent without becoming objectionably tacky.

EXAMPLE 1C Detergent products were made from the base beads of Example 1 B by spraying a normally waxy nonionic detergent, either Neodol (Registered Trade Mark) 23-6.5 or Neodol 45-11, in heated liquid state, onto the tumbling bead surfaces so as to make a product containing 20% or 22% of the nonionic detergent (1 or 2% of proteolytic enzyme, e.g., Maxatase (Registered Trade Mark), and 0.2 or 0.3% of perfume may also be applied to the tumbling beads). The resulting detergent products are excellent heavy duty laundry detergents, especially useful for washing household laundry in automatic washing machines.In addition to their desirable washing properties they are physically and aesthetically advantageous because they are non-dusting and extremely freely flowing, allowing them to be packaged in narrow necked glass and plastic bottles, from which they flow readily.

Although normally crutcher mixes will be made quickly and may be emptied from the crutcher equally fast, sometimes being made within a period of as little as five minutes and being pumped out of the crutcher in as little as five or ten minutes, it is important that the present mixes be able to withstand at least an hour in the crutcher without gelling or solidifying because sometimes holdups of such times are encountered in commercial production. The described crutcher mix is found to be capable of being held for as long as four hours and often longer, without gelling or solidifying.

EXAMPLE 2 In a variation of Example 1 A the temperature of the crutcher was elevated to 1 250F (52 C) and the desired crutcher mix was made and the base beads spray dried therefrom without untoward incident.

EXAMPLES 3A and B, 4A and B, and 5A and B These are other variations of Example 1 A and in these examples the proportions of the various components were varied plus (Example 3A) or minus 10% (Example 3B), plus (Example 4A) or minus 20% (Example 4B) and plus (Example 5A) or minus 30% (Example 5B), maintaining them within the range previously given, and workable crutcher mixes that did not gel and did not solidify for periods of at least an hour were obtained.

EXAMPLES 6, 7 and 8 When either the citric acid (Example 6) or magnesium sulphate (Example 7) was omitted from the mix of Example 1 A or when such was added after the silicate (usually about five minutes thereafter) (Example 8) objectionable gelation often resulted. It was also noted that the presence of the zeolite also tended to promote gelation so the use of the combination of magnesium sulphate and citric material was especially important with respect to the described crutcher mix formulas.

EXAMPLE 9 This is another modification of Example 1 A for the lower solids content crutcher mixes, those of 5060%, the citric acid content was reduced to 0.25% in the formula given in Example 1 A, with the magnesium sulphate content remaining at 1%, and the mix resulting was still satisfactorily non-gelling.

However, use of the larger proportion is desirable for higher solids content mixes and as a safety precaution.

Instead of using Epsom salts and citric acid, equivalent compounds that also result in the same type of anti-gelling action may be employed. Thus, magnesium citrate, anhydrous magnesium sulphate, sodium citrate and various combinations thereof may be employed. Similarly, other zeolites, such as zeolites X and Y may be used and the zeolites may be of various degrees of hydration. Other orders of addition of the various components to the crutcher mix may be followed but it will usually be desirable to have at least some of the source of magnesium ion and the source of citric ion present in the aqueous medium as early in the manufacturing process as is feasible.

When the citric material and magnesium salt are added as described above the solids content of the crutcher mix may exceed 55% and often may be 65 or 70% without undesired gelation taking place within an hour of the completion of the making of the crutcher mix (and often after four hours or more).

However, when either the citric material or the magnesium salt or both are omitted from the mix, premature gelation, thickening and precipitation occur, especially at elevated temperature within the 20 to 700C range and at the higher solids content. In computing the solids contents the water of hydration in the zeolite is considered as a part of the zeolite solid and not as a part of the water content of the crutcher mix. This is because such water of hydration behaves like a solid and is not released into the aqueous medium, being "insoluble" therein during crutching.

EXAMPLES 10A, B and C In these examples the formulation and processing described for Examples 1 A were followed except that the solids content of the crutcher mix, including the water of hydration of the zeolite, was 59.6%, the citric acid content was 0.25% and the proportions of sodium bicarbonate and sodium carbonate were changed. In one such Example, designated Example 1 OA, the sodium bicarbonate content was maintained at 16.3% of the crutcher mix (as is basis) and the sodium carbonate content was 7.6%. In Example 1 0B such proportions were changed to 13.1% and 10.7%, respectively and in Example 100 they were further modified to 10.0% and 13.8%, respectively.Thus, the ratios of sodium bicarbonate to sodium carbonate in the crutcher mixes were 2.1 (Example 10A), 1.2 (Example 10B) and 0.7 (Example 10C) respectively, instead of 2.0, as in Example 1. It was noted that the crutcher mix of Example 1 OB had a higher initial viscosity than that of Example 1 OA, but it was still workable and did not gel over a four-hour holding period. However, the mix of Example 100 solidified during silicate addition, showing the importance of maintaining the proportion of sodium bicarbonate to sodium carbonate in the present compositions within the ranges herein described.

EXAMPLES 1 A to 1 D,11 1 and 1 1G These Examples were made according to the general method described in Example 1A, with the batch temperatures being within the range of 430 to 4600. The compositions of the crutcher mixes are given in Table 1 below. Numerals given in Table 1 are parts by weight except for the percentage of solids, which is a weight percentage.

TABLE I Example 11A 11B 11C 11D 11F 11G Component Tap water 38.9 37.6 35.1 32.7 33.7 33.0 Citric Acid - 0.25 0.25 0.25 0.25 MgSO4, anhydrous 1.0 1.0 1.0 - 1.0 Zeolite 4A (20% hydrated) 22.9 22.9 23.8 24.8 24.8 24.8 Sodium bicarbonate 1 5.6 1 5.6 1 6.3 16.9 1 6.9 16.9 Soda Ash 7.9 7.9 8.2 8.5 8.5 8.5 Sodium silicate (47.5% 14.7 14.7 1 5.4 1 5.9 1 5.9 15.9 solids; Na,O : SiO, Na20.

% Solids (including zeolite 53.4 54.7 56.8 59.0 58.0 58.7 water of hydration) The mix of Example 11 A solidifed in the crutcher during silicate addition. The mixes of Examples 11 B, 11 C and 11 D were satisfactory and formed no gel during silicate additions. The initial viscosities of such mixes were about the same despite the increase in solids content from Example 11 B to 11 D but such viscosities for the mix of Example 11 D were measurably greater than those for the mixes of Examples 11 B and 11 C. With the magnesium sulphate being omitted from the formula, the mix of Example 11 F solidified during silicate addition. The crutcher mix of Example 1 1G did not solidify during silicate addition but did solidify thirty minutes thereafter. Thus, the products of Examples 1 1A, 11 F and 11 G were unsatisfactory.

Reference has been made above to the zeolites having certain values of hardness depletion rate residual hardness.

Expressed another way the zeolites used herein preferably have the ability to deplete a hard water sample containing 4.7 grains/gallon (U.S. gallon) (calcium hardness) (the mixed Ca - Mg hardness being 7.0 grains/U.S. gallon) when added thereto at 0.06% by weight zeolite to a hardness of no more than 2.0 grains/U.S. gallon in 1 minute and no more than 1.0 grains (U.S. gallon) in 10 minutes.

A more detailed description of this text is given in German Specification 241 2837.

Claims (38)

1. A method of retarding or preventing gelation of a miscible and pumpable crutcher slurry comprising sodium bicarbonate, sodium carbonate, sodium silicate and zeolite, which comprises preparing a crutcher slurry of the said material containing a gelation retarding proportion of a gelation retarding material comprising citrate ions and magnesium ions, and mixing such composition in a crutcher during preparation thereof.

2. A method as claimed in Claim 1 in which the miscible and pumpable crutcher slurry contains from 40 to 70% of solids and 60 to 30% of water. of which solids content, on a 100% solids basis, 20 to 45% is sodium bicarbonate, 10 to 30% is sodium carbonate, 5 to 25% is sodium silicate of Na2O : SiO2 ratio within the range of 1:1.4 to 1:3, and 10 to 65% is zeolite, with the ratio of sodium bicarbonate :sodium carbonate being within the range of 1:1 to 4:1, the ratio of sodium carbonate :sodium silicate being within the range of about 1:2.5 to 5:1, the ratio of sodium bicarbonate :sodium silicate being within the range of 1:1 to 8:1 and the ratio of zeolite :silicate being within the range of 1:2 to 10:1.

3. A method as claimed in Claim 1 or Claim 2 in which the gelation retarding material comprises at least 0.4% of the slurry.

4. A method as claimed in Claim 1, 2 or 3 in which the gelation retarding material comprises 0.1 to 2% of citric material and 0.1 to 1.4% of magnesium sulphate.

5. A method of retarding or preventing gelation of a miscible and pumpable crutcher slurry containing from 40 to 70% of solids and 60 to 30% of water, of which solids content, on a 100% solids basis, 20 to 45% is sodium bicarbonate, 10 to 30% is sodium carbonate, 5 to 25% is sodium silicate of Na2O:SiO2 ratio within the range of 1:1.4 to 1:3, and lotto 65% iszeolite, with the ratio of sodium bicarbonate :sodium carbonate being within the range of 1:1 to 4:1, the ratio of sodium carbonate sodium silicate being within the range of 1:2.5 to 5:1, the ratio of sodium bicarbonate:sodium silicate being within the range of 1 :1 to 8:1 and the ratio of zeolite :silicate being within the range of 1:2 to 10 ::1, which comprises preparing a crutcher slurry of the described composition containing a gelation retarding proportion of a gelation retarding material comprising, on a slurry basis, from 0.1 to 2% of a citric material, and from 0.1 to 1.4% of magnesium sulphate, the gelation retarding material comprising at least 0.4% of the slurry, and mixing such composition in a crutcher during preparation thereof.

6. A method as claimed in any one of Claims 1 to 5 in which the crutcher slurry contains from 50 to 65% of solids and 50 to 35% of water, of which solids content 25 to 40% is sodium bicarbonate, 1 3 to 25% is sodium carbonate, 5 to 25% is sodium silicate of Na2O :SiO2 ratio within the range of 1:1.6 to 1:2.6 and 35 to 65% is hydrated, water softening zeolite, the ratio of sodium bicarbonate sodium carbonate is within the range of 1.5:1 to 3 :1, the ratio of sodium carbonate :sodium silicate is within the range of 1:2 to 2:1, the ratio of sodium bicarbonate :sodium silicate is within the range of 2 :1 to 5 :1 and the ratio of hydrated, water softening zeolite :sodium silicate is within the range of 2:1 to 7 :1.

7. A method as claimed in Claim 5 in which the percentages of citric material and magnesium sulphate are in the ranges of 0.1 to 0.8 and 0.1 to 1.2, respectively.

8. A method as claimed in Claim 5 in which the crutcher slurry contains from 50 to 65% of solids and 50 to 35% of water, of which solids content 25 to 40% is sodium bicarbonate, 1 3 to 25% is sodium carbonate, 5 to 25% is sodium silicate of Na2O :SiO2 ratio within the range of 1:1.6 to 1:2.6 and 35 to 65% is hydrated, water softening zeolite, the ratio of sodium bicarbonate : sodium carbonate is within the range of 1.5:1 to 3:1, the ratio of sodium carbonate sodium silicate is within the range of 1:2 to 2:1, the ratio bf sodium bicarbonate :sodium silicate is within the range of 2 :1 to 5:1 and the ratio of hydrated, water softening zeolite :sodium silicate is within the range of 2:1 to 7:1, and wherein the percentages of citric material and magnesium sulphate are in the ranges of 0.1 to 0.8 and 0.1 to 1.2, respectively.

9. A method as claimed in Claim 6 in which the crutcher slurry contains from 55 to 65% of solids and 45 to 35% of water, of which solids content 25 to 35% is sodium bicarbonate, 13 to 20% is sodium carbonate, 8 to 15% is sodium silicate of NA20:SiO2 ratio of 1:2 to 1:2.4, and 35 to 50% is hydrated, water softening zeolite, the ratio of sodium bicarbonate :sodium carbonate is within the range of 1.5:1 to 2.5:1, the ratio of sodium carbonate :sodium silicate is within the range of 1:1 to 2:1, the ratio of sodium bicarbonate :sodium silicate is within the range of 2 :1 to 4:1 and the ratio of hydrated, water softening zeolite :sodium silicate is within the range of 3 :1 to 5:1.

10. A method as claimed in Claim 5 in which the percentages of citric material and magnesium sulphate are in the ranges of 0.2 to 0.6 and 0.4 to 1.1, respectively.

11. A method as claimed in Claim 5 in which the crutcher slurry contains from 55 to 65% of solids and 45 to 35% of water, of which solids content 25 to 35% is sodium bicarbonate, 13 to 20% is sodium carbonate, 8 to 15% is sodium silicate of Na2O :SiO2 ratio of 1:2 to 1 :2.4, and 35 to 50% is hydrated, water softening zeolite, the ratio of sodium bicarbonate :sodium carbonate is within the range of 1.5:1 to 2.5:1, the ratio of sodium carbonate:sodium silicate is within the range of 1:1 to 2:1, the ratio of sodium bicarbonate :sodium silicate is within the range of 2:1 to 4:1 and the ratio of hydrated, water softening zeolite :sodium silicate is within the range of 3 :1 to 5::1, and wherein the percentages of citric material and magnesium sulphate are in the ranges of 0.2 to 0.6 and 0.4 to 1.1, respectively.

12. A method as claimed in Claim 1 or Claim 2 in which the gelation retarding material comprises a magnesium citrate salt.

13. A method as claimed in Claim 12 in which the magnesium citrate salt is magnesium citrate or magnesium acid citrate.

14. A method of retarding or preventing the gelation of a miscible and pumpable crutcher slurry containing from 40 to 70% of solids and 60 to 30% of water, of which solids content, on a 100% solids basis, 20 to 45% is sodium bicarbonate, 10 to 30% is sodium carbonate, 5 to 25% is sodium silicate of Na2O :SiO2 ratio within the range of 1:1.4 to 1:3, and 10 to 65% is zeolite, with the ratio of sodium bicarbonate :sodium carbonate being within the range of 1:1 to 4:1, the ratio of sodium carbonate :sodium silicate being within the range of 1:2.5 to 5:1, the ratio of sodium bicarbonate :sodium silicate being within the range of 1:1 to 8:1 and the ratio of zeolite silicate being within the range of 1:2 to 10 :1, which comprises preparing a crutcher slurry of the described composition in which there is admixed from 0.3 to 3% of magnesium citrate or magnesium acid citrate, on a slurry basis, and mixing such composition in a crutcher during preparation thereof.

1 5. A method as claimed in any one of Claims 1 to 14 in which the crutcher slurry is at a temperature in the range of 20 to 700 C, at atmospheric pressure, and the gel retarding material is incorporated into the slurry before addition thereto of at least some of the sodium silicate.

1 6. A method as claimed in any one of Claims 1 to 1 5 in which the mixing is at a temperature in the range of 20 to 700C, the gel retarding material is incorporated into the slurry before the sodium silicate, and mixing is continued for at least one hour after completion of the making of the crutcher slurry.

1 7. A method as claimed in any one of Claims 1 to 1 6 in which the crutcher slurry temperature is from 25 to 400 C, mixing is effected for at least two hours after completion of the making of the crutcher slurry, and at least a part of the crutcher mix is pumped out of the crutcher to a spray drying tower and is spray dried therein after the said mixing.

1 8. A method as claimed in any one of Claims 1 to 17 in which the citric material is citric acid.

19. A method as claimed in any one of Claims 1 to 18 in which magnesium sulphate is added to the slurry as epsom salts.

20. A method as claimed in any one of Claims 1 to 19 in which from 0.1 to 10% of the crutcher slurry comprises one or more adjuvants or diluents or mixtures thereof.

21. A method as claimed in Claim 1 substantially as specifically described herein with reference to Example lA,2, 3,4,5,9, lOA, 108,118,1 iCor liD.

22. A miscible and pumpable crutcher slurry comprising sodium bicarbonate, sodium carbonate, sodium silicate and zeolite and containing a gelation retarding proportion of a gelation retarding material comprising citrate ions and magnesium ions.

23. A miscible and pumpable crutcher slurry as claimed in Claim 22 comprising from 40 to 70% of solids and 60 to 30% of water, of which solids content, on a 100% solids basis, 20 to 45% is sodium bicarbonate, 10 to 30% is sodium carbonate, 5 to 25% is sodium silicate of Na2O : SiO2 ratio within the range of 1:1.4 to 1 :3, and 10 to 65% is zeolite, with the ratio of sodium bicarbonate :sodium carbonate being within the range of 1:1 to 4:1, the ratio of sodium carbonate :sodium silicate being within the range of 1:2.5 to 5:1, the ratio of sodium bicarbonate :sodium silicate being within the range of 1:1 to 8:1, the ratio of zeolite :silicate being within the range of 1:2 to 10:1.

24. A slurry as claimed in Claim 22 or Claim 23 in which the gelation retarding material comprises at least 0.4% of the slurry.

25. A slurry as claimed in Claim 22, 23 or 24 in which the gelation retarding material comprises 0.1 to 2% of citric material and 0.1 to 1.4% of magnesium sulphate.

26. A miscible and pumpable crutcher slurry comprising from 40 to 70% of solids and 60 to 30% of water, of which solids content, on a 100% solids basis, 20 to 45% is sodium bicarbonate, 10 to 30% is sodium carbonate, 5 to 25% is sodium silicate of Na2O : SiO2 ratio within the range of 1:1.4 to 1:3, and 10 to 65% is zeolite, with the ratio of sodium bicarbonate : sodium carbonate being within the range of 1:1 to 4:1, the ratio of sodium carbonate :sodium silicate being within the range of 1:2.5 to 5:1, the ratio of sodium bicarbonate :sodium silicate being within the range of 1:1 to 8:1 and the ratio of zeolite: silicate being within the range of 1:2 to 10:1, and which solids content includes, on a slurry basis, a gelation retarding proportion of a gelation retarding material comprising 0.1 to 2% of a citric material, and from 0.1 to 1.4% of magnesium sulphate, with the total of such citric material and magnesium sulphate being at least 0.4% of the slurry.

27. A slurry as claimed in Claim 22 or Claim 23 in which the gelation retarding material comprises a magnesium citrate salt.

28. A slurry as claimed in Claim 27 in which the magnesium citrate salt is magnesium citrate or magnesium acid citrate.

29. A miscible and pumpable crutcher slurry comprising from 40 to 70% of solids and 60 to 30% of water, of which solids content, on a 100% solids basis, 20 to 45% is sodium bicarbonate, 10 to 30% is sodium carbonate, 5 to 25% is sodium silicate of Na2O :SiO2 ratio within the range of 1:1.4 to 1:3, and 10 to 65% is zeolite, with the ratio of sodium bicarbonate : sodium carbonate being within the range of 1:1 to 4:1 , the ratio of sodium carbonate : sodium silicate being within the range of 1:2.5 to 5:1, the ratio of sodium bicarbonate :sodium silicate being within the range of 1:1 to 8:1 and the ratio of zeolite : silicate being within the range of 1:2 to 10:1, and which solids content includes, on a slurry basis, a gelation retarding proportion of magnesium citrate or magnesium acid citrate, in an amount of 0.3 to 3% of the slurry.

30. A miscible and pumpable slurry as claimed in Claim 22 substantially as specifically described herein with reference to Example 1 A, 3, 4, 5, 9, 1 OA, lOB, 118, 1 C or 11 D.

31. A method of making a particulate base material in bead form, suitable for absorbing detergent e.g. non-ionic detergent to make a built heavy duty synthetic organic detergent composition, which comprises making a miscible and pumpable slurry in a crutcher by a method as claimed in any one of Claims 1 to 21, pumping the slurry out of the crutcher in ungelled and readily pumpable state and spray drying the slurry to particulate bead form.

32. A method as claimed in Claim 31 substantially as specifically described herein with reference to Example 1 B.

33. A particulate base material in bead form, suitable for absorbing detergent to make a built heavy duty synthetic organic detergent composition whenever made by a method as claimed in Claim 31 or Claim 32.

34. A method of making a built heavy duty synthetic organic detergent composition, which comprises causing a detergent to be absorbed into base bead as claimed in Claim 33.

35. A method as claimed in Claim 34 substantially as specifically described herein with reference to Example 1C.

36. A built heavy duty synthetic organic detergent composition whenever made by a method as claimed in Claim 34 or Claim 35.

37. A particulate base material in bead form, suitable for absorbing detergent to make a built heavy duty synthetic organic detergent composition comprising 20 to 35% of sodium bicarbonate, 10 to 20% of sodium carbonate, 30 to 45% of zeolite, 10 to 20% of sodium silicate, and 0.5 to 4% of magnesium citrate or magnesium acid citrate or 0.3% to 2.0% of citric material and 1 to 2% of magnesium sulphate, 0 to 10% of one or more adjuvants or diluents of both and 3 to 10% of moisture, and optionally not more than 20% of sodium sulphate as a diluent.

38. A built heavy duty synthetic detergent composition comprising 1 5 to 25% non-ionic detergent 15 to 25% of sodium bicarbonate, 5 to 15% of sodium carbonate, 5 to 15% of sodium silicate, 25 to 35% of zeolite, optionally 1 to 3% of fluorescent brightener, optionally sufficient bluing to colour the product and whiten the wash, 3 to 10% moisture, and 0.3 to 3% of magnesium citrate or magnesium acid citrate or 0.25% to 1.2% of citric material and 0.8 to 2% of magnesium sulphate, and optionally not more than 20% of sodium sulphate as a diluent.