GB1574901A

GB1574901A - Lignite-impregnated material

Info

Publication number: GB1574901A
Application number: GB4647575A
Authority: GB
Original assignee: KAPAG Manufacturing CO Ltd
Current assignee: KAPAG Manufacturing CO Ltd
Priority date: 1975-11-11
Filing date: 1975-11-11
Publication date: 1980-09-10
Also published as: BE848294A

Description

(54) LIGNITE-IMPREGNATED MATERIAL (71) We, KAPAG MANUFACTURING Co. LIMITED, a British Company, of Quarry Works, Kingsteignton Road, Newton Abbot, Devon, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to a compound for use as a growing medium and to a process for the manufacture of the medium. It is also concerned with a method of producing turf and with the manufacture of a compound including grass, which is edible by cattle.

According to one aspect of the invention a compound for use as a growing medium comprises a cellulosic material impregnated with lignite. By "cellulosic material" is meant material, such as paper or cardboard, derived from cellulose, i.e. from the basic substance of the cellular tissue of plants or trees. "Impregnated" is used herein, in its conventional sense, as meaning that particles of the lignite are infused into the cellulosic material.

The growing medium may be of flaky or granular character of high water-absorption capability and can be readily bagged for transport. The proportion by dry weight of lignite to cellulosic material may be between 3:1 and 8:1, and is preferably approximately 4:1.

The lignite preferably has a maximum particle size to pass a 8" mesh screen, the particle size of the lignite desirably varying from such maximum particle size to dust, there being not more than 15% of b" particles. The compound preferably has a total moisture content of between 20% and 50% by weight, preferably about 26% by weight, the moisture content being dependent on the relative proportions of the solid components of the compound which, in addition to cellulosic material and lignite, may comprise up to 12% by weight of peat and between 15%, and 30% by weight of a particulate filler.

Although the flakes or granules of the compound may vary in size, the compound will preferably pass up to 15% through a 0.050" mesh screen, 60% through a 0.200" mesh screen, 10% through a 0.300" mesh screen and 5% through a 0.400" mesh screen. The cellulosic material may comprise waste paper or cardboard, and preferably comprises waste paper embodying recycled material and which is unsuitable for further recycling in paper manufacture.

The particulate filler is preferably sharp sand which is of jagged-edge or otherwise irregular shape so as to ensure that a large number of drainage channels are always provided.

The process of manufacturing the compound comprises thoroughly mixing ground lignite with cellulosic material the fibres of which are in a fine state of separation in order to impregnate the cellulosic material with the lignite. It is preferable that the lignite should be mixed initially with the particulate filler prior to addition thereto of the cellulosic material.

The impregnation may be carried out with the cellulosic material in a dry macerated (pulverised) state followed by the addition of water as a binding agent. The cellulosic material may comprise waste paper fed into a mill and pulverised to form a dry, light, fluff-type substance.

As an alternative, the impregnation may be carried out with the cellulosic material in a state of aqueous saturation, the waste paper being fed to a digester provided with low heat elements and with paddle-type or bubble agitation means, or both. After a suitable period of digestion the ground lignite and particulate filler are added and digestion is continued for a further period during which the finer particles of lignite form a type of humic acid solution which impregnates and coats the paper pulp.

According to another aspect of the invention there is provided a material for feeding to cattle comprising turves consisting of grass grown using a compound as defined above. The invention also provides a method of producing turf wherein grass seed is mixed with a compound as defined above, the mixture is held under conditions favouring germination of the seed, preferably until chitting of the seed has occurred, whereupon the mixture is spread over a flat supporting surface and, when predetermined growth has taken place, the grown turf is removed from the supporting surface.

Quite apart from its growing and edible qualities, the lignite-impregnated cellulosic material, when dried to a moisture content of about 26% by weight, possesses high liquid-absorption properties and has been found to be efficacious as a litter material for cats and other domestic animals.

In carrying the invention into effect according to one mode, cellulosic material is fed into a mill and is pulverised or macerated to form a dry, light, fluffy substance. The cellulosic material can be waste paper, or cardboard, such material at the present time constituting a wastedisposal problem particularly as regards waste paper which has itself been made from waste materials. Maceration (pulverising) of the material in the dry state ensures that the cellulosic fibre is well separated and in suitable condition for admixture with the other solid components of the compound. Lignite and sand are fed into a mixing vessel, the lignite being of maximum particle size to pass a T" mesh screen and with not more than 15% of jff particles, the remainder being down to dust, and a first mixing operation is carried out.

The macerated paper is then added and a second mixing operation effected. Water is added next and a third mixing operation performed, the final addition being peat which is admixed with the remainder of the mixture during a fourth mixing operation.

The four mixing operations are normally provided by a single continuous mixing process carried out preferably in a paddletype mixer.

The amounts of the ingredients of the mixture in percentages by weight can be varied as follows:- Lignite 16 to 36, Sand 15 to 30, Paper 3 to 13, Water 20 to 50, and Peat 0 to 12 In a preferred composition the percentages by weight of the ingredients are as follows: Lignite 26.3 Sand 29.5 Paper 7.4 Water 26.1 Peat 10.7 It should be pointed out that although the weight of lignite in the compound is significantly greater than the weight of paper, the paper has the greater bulk so that it is impregnated with the lignite.

The mixture is by this time in granular or flake form, the flakes or granules varying in si7e though, in general, they will pass up to 15% through a 0.050" mesh screen, 60 /a through a 0.200" mesh screen, 10% through a 0.300" mesh screen and 5% through a 0.400" mesh screen. If necessary, the flakes or granules are dried in a stream of warmed air until the total moisture content of the finished product is 26.1 /n In an alternative method of producing the compound, waste paper is fed as a fully saturated aqueous pulp to a digester in which it is agitated under low heat with 40 more water. After a suitable period of digestion, for example 30 minutes, the ground lignite and sand are added to the pulp.Digestion is continued for a further period of, for example, 20 minutes whereafter the peat is added. At the completion of the total digestion period of the order of one hour, the ligniteimpregnated pulp is discharged and excess water allowed to drain off. The impregnated pulp is then passed between rollers to express some of the liquid therefrom. After leaving the rollers, the pulp is delivered to a continuous-flow rotating drum in which the pulp is formed into nodules of indiscriminate size which are fed to an extrusion mill provided with dies which produce granules or flakes of the required size as indicated above.

In use as a growing medium for the production of turf, the compound (produced by either of the methods described above) is mixed with the appropriate proportion of grass seed and maintained in a moistened condition in a greenhouse until germination of the seed has been effected. The pH of the compound should be appropriate to the seed to be grown and it is accordingly controlled by the addition of suitable buffering agents during the mixing process. The pH will normally be about 7 but can vary from 5 to 9 depending on what plants are to be grown since a pIll which is appropriate to one particular grass seed might not be suitable for another, or for certain vegetables or flowers, the compound having been developed particularly in relation to the growing of grass but being capable of use in relation to the growing of a large variety of crops.

After germination of the grass seed, the mixture is spread in a thin layer upon an impervious bed afforded by, fdr example, flexible plastics sheeting. Lavish watering is continued since the use of lignite as a major constituent of the growing medium ensures the absence of root rot, and the grass grows rapidly to provide luxuriant growth and strong intertwining root formation within the thin layer of compost. When growth is complete, the turf and compound may be rolled up as elongated strips with the strong root formation providing the requisite tensile strength without further support, though the plastics sheeting may, if desired, be rolled up with the turf as a backing to be stripped off before laying. The turves may, alternatively, be used as a cattle feed since the particular composition of the growing medium is edible by cattle.

Although the primary purpose of the compound is for use as a growing medium for the production of grass or other crops, the water absorption characteristics of the lignite-impregnated cellulosic material render it suitable for use as a cat litter.

WHAT WE CLAIM IS: 1. A compound for use as a growing medium comprising a cellulosic material impregnated with lignite.

2. A compound according to claim 1 of flaky or granular character.

3. A compound according to claim 1 or 2, wherein the proportion by dry weight of lignite to cellulosic material is between 3:1 and 8:1.

4. A compound according to any of the preceding claims, wherein the proportion by dry weight of lignite to cellulosic material is approximtely 4:1.

5. A compound according to any of the preceding claims, wherein the lignite has a maximum particle size to pass a " mesh screen.

6. A compound according to claim 5, wherein the particle size of the lignite varies from a maximum a" to dust, there being not more than 15% of " particles.

7. A compound according to any of the preceding claims, wherein the total moisture content is about 26%.

8. A compound according to any of the preceding claims, wherein the compound comprises flakes or granules varying in size, the compound passing up to 15 /n through a 0.050" mesh screen, 60% through a 0.200" mesh screen, 10% through a 0.300" mesh screen and 5% through a 0.400" mesh screen.

9. A compound according to any of the preceding claims wherein the cellulosic material comprises waste paper or cardboard.

10. A compound according to any of the preceding claims, wherein the ligniteimpregnated cellulosic material includes between 15% and 30 by weight of a particulate filler.

11. A compound according to any of the preceding claims, wherein the ligniteimpregnated cellulosic material includes up to 12% by weight of peat.

12. A compound according to claim 1, including the following ingredients in percentages by weight: Lignite 16 to 36 Sand 15 to 30, Paper 3 to 13, Water 20 to 50, and Peat 0 to 12.

13. A compound according to claim 12, wherein the percentages by weight of the ingredients are: Lignite 26.3 Sand 29.5 Paper 7.4 Water 26.1 Peat 10.7 14. A process of manufacturing a compound for use as a growing medium which comprises thoroughly mixing ground lignite with cellulosic material the fibres of which are in a fine state of separation in order to impregnate the cellulosic material with the lignite.

15. A process of manufacturing a compound according to claim 14, wherein the impregnation is carried out with the cellulosic material in a dry macerated (pulverised) state followed by the addition of water as a binding agent.

16. A process of manufacturing a compound according to claim 14, wherein the impregnation is carried out with the cellulosic material in a state of aqueous saturation.

17. A process of manufacturing a compound according to claim 14 or 15, wherein the cellulosic material comprises waste paper fed into a mill and pulverised to form a dry, light, fluffy substance.

18. A process of manufacturing a compound according to any of claims 14 to 17, wherein the lignite is first mixed with a particulate filler and the cellulosic material is mixed with the mixture of lignite and filler to effect said impregnation of the cellulosic material with the lignite.

19. A process of manufacturing a compound according to claim 18, wherein water is added to the mixture of filler and lignite-impregnated cellulosic material and mixing thereafter continued.

20. A process of manufacturing a compound for use as a growing medium substantially as hereinbefore described.

21. A compound produced by the method

Claims

of claim 20.

22. A material for feeding to cattle comprising turves each consisting of a body of the compound according to claim 1 or claim 21 having grass grown thereon.

23. A method of producing turf wherein grass seed is mixed with a compound according to claim l or claim 21, the mixture is held under conditions favouring germination of the ed preferably until chitting of the seed has occurred, whereupon the mixture is spread over a flat stspporting surface and, when predetermined growth has taken place, the grown turf is removed from the supporting surface.