GB2169484A

GB2169484A - Animal litter

Info

Publication number: GB2169484A
Application number: GB08500659A
Authority: GB
Inventors: Torben Christen Hansen
Original assignee: Individual
Current assignee: Individual
Priority date: 1985-01-11
Filing date: 1985-01-11
Publication date: 1986-07-16
Also published as: GB8500659D0; GB2169484B

Abstract

Cat- or other animal litter of high absorption capacity and long-lasting deodorizing effect is produced by crushing hardened lightweight or normal weight concrete, cement mortar or cement paste made with hydrated lime, portland cement, portland-pozzolan cement, slag cement or high-alumina cement as a binder. Raw materials may be produced specifically for the purpose of production of cat litter, or they may be obtained as waste products when old concrete structures are demolished and the debris is crushed in order to produce coarse recycled concrete aggregate for the production of new concrete or for road construction purposes. Crusher fines from recycling plants are ideally suited for production of cat litter. Suggested uses of the invention include for example: Animal litter in domestic households, zoological gardens, animal farms or on other premises where objectionable smell from urine or fecal matter is a problem.

Description

SPECIFICATION Cat litter and a method for production of cat litter on the basis of crushed hardened concrete, cement mortar and cement paste The general objective of the invention is the production of dense cat litter of exceptional quality having an exceptional combination of physical and chemical characteristics including high absorption capacity and long lasting deodorizing effect. Moreover, the invention provides forthe production of such high quality cat litter by the crushing of hardened concrete, cement mortar and cement paste. Such raw materials can either be produced forthe specific purpose of manufacturing cat litter, or they can become available as debris when old concrete structures are demolished and the debris is crushed in order to produce coarse recycled concrete aggregate.

Crusherfines from crusher plants which recycle old concrete are ideally suited for production of cat litter.

Such old concrete may be anything from light-weight autoclaved concrete to high-strength structural concrete. Crushing can bedone by processes which are readily established and maintained even by personel not having any echnical training.

Concrete is a building material. It is a mixture of natural or manufactu red fine aggregate, natural or manufactured coarse aggregate, water and hydraulic cement such as portland cement, portland-pozzolan cement, slag cement or high-alumina cement. Mortar is a mixture of natural or manufactured fine aggregate, water and one or more of the above-mentioned cements. Cement paste is a mixture of one or more of the above-mentioned cements and water. In concrete, mortar or paste, hydrated lime can replace part or all of the above-mentioned cements. When above-mentioned cements react witch water, concrete, mortar and paste harden. In the process of hardening a certain amount of calcium hydroxide is formed and locked into the porous microstructure of the hardened cement paste.

When hardened concrete, mortar or cement paste, for example from a demolished structure, is crushed in a mechanical crusher or by any other means, a certain amount of material is generated which will pass an ASTM 3/8" sieve or an ISO 8 mm sieve.

Forwhat concerns this invention, it has been demonstrated thatthe resulting fine gravel or sand below 3/8" or 8 mm, which derives from crushed concrete, mortar or cement paste, can be used as deodorizing cat- or other animal litterwithout further processing, orafterscreening on an 0.5 mm sieve or other appropriate small-mesh sieve, or after air sifting to remove the finest particle fractions if a dust-free litter is desired.

It has been demonstrated that urine from cats will be absorbed by the hardened cement paste in the crushed product where it is neutralized by the hydrated lime in the porous microstructure to such an extent, thatthe water from the urine which eventually evaporates from the litter is completely odorless.

Under normal use, the deodorizing effect will last for several weeks provided that solid fecal matter is removed from the litter at regular intervals. This is in contrast to many conventional cat litters which must be changed every few days because ofthe repugnant smell of cats urine. It should be mentioned that crushed concrete cat litter also removes the smell of fecal matter, but it is advisableto remove such matter for other and obvious reasons.

It has also been demonstrated that paws or skin of cats which use the crushed concrete litter will not be burnt or otherwise irritated by the hydrated lime even after prolonged use. On the contrary, cats demonstrate their satisfaction with the crushed product by intensive and prolonged digging and scraping in the litter. Due to the relatively heavy weight of the crushed concrete litter (approximate density, 2100 kg/m3) compared to conventional litters, such activities result in generation of much less dust and flying debris than does the use of conventional lightweight litters. Also due to the relatively heavyweight, litter particles easilyfallfrom paws and no solid litter particles or paw prints are observed on floors after cats have been in the litter.

2. Example Concrete was produced with 357 kg/m3 of portland cement, 175 kg/m3 of water, 670kg/m3 offine aggregate passing a 5 mm sieve and 1048 kg/m3 of coarse aggregate between 30 and5mm. Standard 15by30 cm cylinders, such as are used for determination of compressive strength, were cast from this concrete and cured for 2 days in water at 20 C, then accelerated cured foran additional 37 days in water at 40 C in order to stimulate the long-term hydration of old concrete.

The cylinders were crushed in a laboratory jaw crusher which was set at an opening of 25 mm with the jaws ofthe crusher in a closed position. 20 weight percent of the crusher products passed a nominal 5 mm sieve.and approximately 4 weight percent passed the 0.5 mm sieve. Density of the product was approximately 2100 kg/m3 and water absorption was approximately 10 weight percent ofthe dry material.

Thermo GravimetricAnalysis indicated thatthe product below the 5 mm sieve contained approximately 4 weight percent of calcium hydroxide (hydrated lime).

4.5 kg ofthe product, which passed the 5 mm sieve but was retained on the 0.5 mm sieve, was placed in an 0.3 by 0.4 by 0.1 m plastictrayto a height of 0.05 m.

The tray was piaced in a 4 by4 by 3 m kitchen, which was kept at a temperature of 20 C with no artificial ventilation.

Without changing the litter, the traywas used for one month astoiletfacilityfortwo adult female cats (4.5 and 5.5 kg). The cats were let out in a garden for one hour every morning to relieve themselves, but kept indoors for the rest ofthe days. At nightthey slept in the kitchen with the doors closed. Larger pieces of excrements were removed from the litter at regular intervals. After one month of continuous use when the experiment was interrupted the litter was still completely odorless. This is in contrastto most conventional litters which must be changed everyfew days because of bad odor.

No burns or other skin irritations were observed on the cats paws or other parts ofthe body. On the contrary the cats demonstrated their profound satisfaction with the change from lightweightto dense litter by more prolonged scraping and digging in the crushed concrete iitterthan in conventional litter.

Moreover, such scraping and digging resulted in generation of much less dust and fiying debris in the kitchen than was the case when conventional cat litter was used. No cat paw prints or litter particles were everfound on floors of adjoining rooms.

Claims

1. Cat-orotheranimal litter produced by the crushing of hardened concrete, cement mortar or cement paste produced with portland cement, portland- pozzolan cement, slag cement, high-alumina cement or hydrated lime as a binder. Crushing must result in a product of less than 10 mm maximum particle size. Such products can be mixed with other absorbent materials or waste products such as charcoal,crushed bricks or conventional cat- or other animal litter. Suggested uses ofthe invention include forexampleanimal litter in domestic households, in zoologicai gardens, on animal farms and on other premiseswhereobiectional smell from urineorfecal matterisa problem.

2. Cat- or other animal litter produced bythe crushing of hardened concrete, cement mortar or cement paste produced with portland cement, portland-pozzolan cement, slag cement, high-alumina cement or hydrated lime as a binder. Crushing should result in a product less than 8 mm in maximum particle size which should be screened or air-sifted to remove particles below approximately 0.5 mm. Such products can be mixed with other absorbent materials orwaste products such as charcoal, crushed bricks or conventionalcat-orotheranimal litter. Suggested uses of the invention includefor example animal litter in domestic households, in zoological gardens, on animal farms oron other premises where objectionable smell from urine orfecal matter is a problem.