Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Clay or inorganic aluminosilicate salt component
Reexamination Certificate
1999-06-25
2001-04-24
Douyon, Lorna M. (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Clay or inorganic aluminosilicate salt component
C510S477000, C510S512000, C510S532000, C510S533000, C423S700000, C423S701000, C423S714000, C502S062000, C502S085000
Reexamination Certificate
active
06221835
ABSTRACT:
BACKGROUND
Type-A zeolite has been used for many years as a major component in powder detergents. It has long been known in the art that if the zeolite has an alkalinity above normal, such higher alkalinity can be easily addressed by adjusting the acidic compounds in spray dry crutch operations.
It is common practice to ship type-A zeolite in powder form to the detergent manufactures by railcar. A long standing goal in the art has been the development of an effective way of increasing the loading capability of the zeolite per unit volume of container space. In this way it would be possible for a greater quantity of the zeolite product to be carried in a railcar or other shipping container or vessel. In addition, larger quantities of the zeolite could be stored in silos or other storage vessels both at the site of the manufacturer and at the site of the detergent producers.
Type-A zeolite particles typically range in size from about 1 micron to about 40 microns. In preliminary studies connected with this invention it was discovered that if dry particulate type-A zeolite is subjected to size reduction in, say, a hammer mill, some increase in loading capability per unit volume of container space can be achieved. However, there is a limit to which such particles can be subdivided in this manner. Once the particles reach a sufficiently small size, they tend to agglomerate and thereby form particles which are below, but which nevertheless approach, the particle size before milling or grinding.
It is thus a principal objective of this invention to find a way of increasing the loading capability of zeolite per unit volume of container space, especially in the case of type-A zeolite. It would be particularly advantageous if this objective could be achieved without any material adverse effect upon the properties of the zeolite for end use application in the manufacture of powder detergents.
THE INVENTION
This invention is deemed to fulfill the foregoing objective in a highly effective manner. Indeed, it has been found possible to accomplish the objective while at the same time improving upon other properties of type-A zeolite for usage as a detergent builder in powder detergents. Thus in addition to increased loading capability, the type-A zeolites of this invention, if properly prepared, normally will possess improved performance in at least one of the following additional properties: lack of particles larger than 30 microns, increased calcium depletion rate, and/or decreased alkalinity.
In one of its embodiments this invention provides a process of increasing the loading capability of a zeolite, which process comprises:
a) contacting water-wet zeolite filter cake while on the filter or after removal from the filter with a treating agent to form a mixture containing treating agent, water, and zeolite, the treating agent being a substance capable of transferring protons to one or more bases that exist in the mixture, the amount of treating agent being sufficient to cause a detectable decrease in the pH of the mixture, but insufficient to reduce the pH of the mixture to below about 11;
b) either (i) drying the mixture from a), or (ii) mixing a sufficient amount of dry zeolite powder with the wet mixture from a) to form a more readily handleable wet blend, and drying the wet blend; and
c) physically subdividing dried zeolite from b) to form a finely-divided zeolite that is devoid, or at least substantially devoid, of any particles larger than about 30 microns, and preferably that is devoid, or at least substantially devoid, of any particles larger than about 20 microns.
The term “substantially devoid” as used herein, means that the zeolite composition formed by the process contains, if any, no more than about 3 wt %of particles greater than 30 microns in size, and preferably no more than about 3 wt%, if any, of particles greater than 20 microns in size. Even more preferably, no more than 3 wt %of the particles, if any, are of a size greater than 10 microns. It is interesting to note that this invention has made it possible to provide laboratory produced zeolite compositions having no detectable amount of particles greater than about 6 microns in size.
In another embodiment of this invention the treating agent is added to the filter cake while the filter cake remains on the filter, the treated filter cake is then removed from the filter and then steps b) and c) above are carried out.
A further embodiment is a process of increasing the loading capability of a zeolite, which process comprises:
a) removing the filter cake from the filter, preferably after it has been washed with water;
b) forming a stirrable mixture of the removed zeolite and water, said mixture having a pH above about 11;
c) introducing into, and thoroughly dispersing within, said mixture a substance capable of transferring protons to one or more bases that exist in the mixture, the amount of such substance introduced into the mixture being sufficient to produce a detectable decrease in the pH of the mixture, with the proviso that the pH of the mixture does not fall below about 11;
d) either (i) drying the mixture from c), or (ii) mixing a sufficient amount of dry zeolite powder with the wet mixture from b) to form a more readily handleable wet blend, and drying the wet blend; and
e) physically subdividing dried zeolite from d) to form a finely-divided zeolite that is devoid, or at least substantially devoid, of any particles larger than 30 microns, and preferably that is devoid, or at least substantially devoid, of any particles larger than about 20 microns.
For convenience, the substance having the ability to transfer protons to one or more bases present in the initial zeolite mixtures is sometimes referred to hereinafter as the “treating agent.”
Still another embodiment of this invention is a composition which comprises (i) a synthetic zeolite, preferably a type-A zeolite, and (ii) from about 0.2 to about 4.5 wt%, and preferably from about 0.2 to about 1.5 wt%, based on the total weight of (i) and (ii), of an electrolyte. Such electrolyte results from the introduction into the zeolite cake formed during the production of the zeolite, of a substance which transferred protons to one or more bases that existed in the zeolite filter cake formed during the production of the zeolite. In other words, the treating agent used in forming such zeolite composition is the precursor of the electrolyte which is present in the above composition.
Further embodiments of this invention provide synthetic zeolite compositions, preferably type-A zeolite compositions, in which the composition contains no more than about 3 wt %of particles greater than 30 microns in size, and preferably no more than about 3 wt %of particles greater than 20 microns in size. In still further embodiments of this invention, there are provided a synthetic zeolite composition, preferably a type-A zeolite composition, in which no more than about 3 wt %of the particles are of a size greater than 10 microns.
Preferred compositions of this invention comprise in combination (i) a synthetic zeolite, preferably a type-A zeolite, and (ii) from about 0.2 to about 4.5 wt%, and preferably from about 0.2 to about 1.5 wt%, based on the total weight of (i) and (ii), of an electrolyte formed from a treating agent which, before inclusion in said mixture, was capable of transferring protons to one or more bases that existed in the zeolite filter cake formed during the production of the zeolite, the composition being further characterized in that the composition contains no more than about 3 wt% of particles greater than 30 microns in size, more preferably no more than about 3 wt %of particles greater than 20 microns in size, and most preferably no more than about 3 wt %of particles greater than 10 microns in size.
So far as is presently known, it has been impossible to produce any of the compositions of this invention prior to this invention.
As is well known in the art, zeolite is formed by mixing sodium hydroxide, sodium aluminate, and sodium silicate in water to produce a gel-phas
Coury Joseph E.
Goins Dixie E.
Hu Patrick C.
Langlois, Jr. Conrad J.
Albemarle Corporation
Douyon Lorna M.
Spielman, Jr. E. E.
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