GB2109023A - Recycling of paper and other materials - Google Patents

Abstract

A method of making solid articles from a pulp or paste of saturated paper. A surfactant and/or a foaming agent is added to an aqueous solution containing the paper or pulp and the articles are then moulded, extruded or otherwise shaped. Methods of making blocks or pots for seed propagation are described and also methods of making fuel blocks employing a combustion promoting agent such as hydrogen peroxide and/or fuel components such as coal dust, anthracite dust etc.

Description

SPECiFICATiON RccOlng of paper X mat eiele The present invention relates to the recycling of paper and other rnaterials, and particulaly to methods of manufacturing useful products utilising waste paper and like fibrous materials, and to such products themselves.

It has long been known that saturated scraps of paper can be made up into or over a mould to form articles which have a substantial degree of rigidity when dried. Such material, known as papier each, has then usually been rendered waterproof by the addition of an impermeable coating of paint or other material. This process provides a lightweight relatively rigid, but not very strong article capable of being used for light duties.

The present invention relates generally to the production of articles from saturated paper, and according to one aspect of the invention solid articles are made by forming a pulp or paste of saturated paper or like fibrous material by agitating the material in an excess quantity of water or aqueous solution of other chemicals, adding to the pulp thus formed a composition including or comprising a surfactant and/or a foaming agent, and subsequently utilising the paste thus constituted in the production of moulded, extruded or otherwise shaped articles. If a foaming agent is added to the pulp or paste it is preferable for the subsequent forming processes to avoid the use of excess pressures for expressing the liquid or for obtaining the required shape so that the finished articles are lightweight and porous.For other uses, however, the foaming agent may be omitted and pulp compressed to form relatively dense solid articles when dried.

This can, of course, be done notwithstanding the inclusion of the foaming agent, and articles obtained by pressing or moulding a paste like material in which a foaming agent has been incorporated will produce an intermediate density article.

It is envisaged that not only hollow articles, but also solid articles for special purposes may be made by the method of the present invention. In particular, it is envisaged that blocks or pots for plant propagation purposes may be formed using a variation of the basic technique, and according to another aspect of the present invention a method of producing blocks or pots for plant propagation purposes comprises the steps of forming a pulp from paper or other biodegradable fibrous material in water or an aqueous solution, adding to the pulp a composition including a surfactant and/or a foaming agent, further agitating the pulp to ensure thorough mixing, draining excess liquid from the resulting mixture and forming this latter to shape in a mould or by extrusion and allowing it to dry.Advantageously one or more plant nutrients are incorporated in the final product, either by inclusion in the aqueous solution with which the initial pulp or paste is formed, or by inclusion in the composition added thereto, or by addition to the dried product by spraying or subsequent immersion.

The value of blocks or pots formed in this way as containers for plants, or as recepticles for seeds, may be enhanced by further including in the manufacturing process the step of incorporating peat or other growing medium component in the pulp before or after admixture of the said composition including the surfactant and/or the foaming agent.

The shape of the blod:s may be chosen as required for various purposes, although simple rectangular blocks or square blocks may prove to be the most satisfactory. Cylindrical blocks could also have advantages for the propagation of seeds or seedlings since, by forming a recess in one end face, the seed or seedling can be equally spaced from the side wall in all directions. Such propagating pots can be used to start off seeds or grow seedlings, and can be planted out into their final positions without requiring any disturbance to the roots so that no setback of the plant is experienced upon transplanting as is usual when "pricking out".

The present invention can also be adapted to produce blocks of material for other purposes, in particular for use as fuel blocks or briquettes. Paper or like cellulosic materials (for example wood pulp or rag pulp) are high in hydrocarbons and represent a potentially valuable fuel source particularly if combined with other fuel sources such as coal dust, sawdust, wood chippings and the like which are not readily usable as fuel.

According, therefore, to a further aspect of the present invention a method of producing fuel blocks (which term is herein to be understood to refer to any form or shape or combustible fuel unit such as nuts, briquettes and the like) comprises the steps of forming a pulp or paste from paper or otherfibrous or cellulosic base material in water or an aqueous solution, adding to the pulp a composition comprising or including a surfactant and/or a foaming agent and agitating the resulting mixture to ensure thorough dispersion of the constituents and draining the surplus liquid from the pulp thus formed, and forming the drained pulp into blocks or briquettes (such as in a mould), a combustion promoting agent being added to the base material either in the aqueous solution or in the composition added to the pulp or subsequent to the initial draining stage.

The combustion promoting agent may be of any suitable form: for example, it may be an oxidising agent which releases oxygen on heating or in reaction with combustion products produced-upon igniting the block.

This method is one in which density of material is an advantage so that pressure may be applied to express surplus liquid from the pulp or paste during the drying stage notwithstanding that this may reduce or negate the porosity introduced by the foaming agent.

A dry combustible material in the form of powder, flakes or granules may also be added to the pulp during or before drying stage, and a binder such as wood glue, cellulose paste or other bonding agents may also be incorporated before the material is dried.

The present invention also comprehends a composition for use in the production of fuel blocks, comprising a surfactant combined with a foaming agent and a combustion promoting agent. The combustion promoting agent may be hydrogen peroxide in a suitable dilution.

The present invention also comprehends a combustible material comprising a bulk fibrous pulp material expanded by the addition of a foaming agent, formed into blocks and dried to a moisture content less than 20% by weight. Preferably, however, the moisture content is less than 10% by weight the combustible material may alternatively be formed from a bulk fibrous pulp material to which a surfactant has been added whilst in its saturated state, together with a combustion promoting agent, foliowing which, as before, the material is formed into blocks and dried to a low moisture content. The bulk fibrous material may be further reinforced by the addition of a bonding agent.

Preferably, the fibrous bulk pulp material is paper, particularly newsprint, although cardboard and other board and paper derivatives can be employed.

Likewise, any other combustible material may be incorporated into the fuel with the pulp, such as coal, coal dust, coke, charcoal (either in pieces or as a dust), wood, cotton rags and/or vegetable residues (the latter being suitably dehydrated).

Examples of the present invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic diagram illustrating a first step in the method of the invention; Figure 2 is a schematic view illustrating a second stage in the performance of the method of the invention; Figure 3 is a cross sectional view of a hand press suitable for performing a third stage in the method of the invention; and Figure 4 illustrates products made with the method of the invention.

In performing the method illustrated by the drawings a quantity of hot water is placed in a receptacle 11 and a number of sheets of crumpled newspaper introduced into it. The ratio of water to paper must be such that there is substantially more water than that required completely to saturate the paper.

Agitation of the contents within the receptacle 11 can advantageously be employed to encourage breaking up of the paper into a pulp. After sufficient agitation has broken the paper into a fairly fine pulp or paste agitation is stopped and a chemical composition comprising a foaming agent and a liquid detergent is in.roduced. The quantity of this composition may vary from 1% to 5% of the quantity of liquid used in forming the original pulp. Further agitation with the stirrer 12 then takes place. In this example the resultant articles are to be used for the propagation of flowers, and if desired further additions of plant nutrients and/or other growing media such as peat and the like can be made at this stage.When the constituents have been thoroughly mixed they are turned into a mould comprising a cylindrical wall 14 open at each end and containing a plurality of perforations 15 in the region from one end 16 to approximately the mid point of the cylinder. The cylinder 14 is placed with the end 16 on the ground or a suitable hard surface before the paste or pulp is introduced into it, and then a piston 17 is fitted into the open end of the cylinder 14 and manual pressure applied to a handle 18 thereof to express surplus liquid from the paste through the perforations 15.

When sufficient liquid has been expressed to make the pulp self supporting the cylinder 14 is drawn up over the piston 17, manual pressure being maintained on the handle 18, to leave the block 19 of material standing on the drainage surface. This is then left until it has dried down to a moisture content less than 20% following which it can safely be moved without risk of breakage. The blocks can be stored in this state until it is required to use them, for which purpose they are saturated in water, a small hole formed in one end, and a seed or seedling placed in the recess: the hole may be filled with soil or other growing medium or may have the material scooped out replaced.

Avariation of this method can be used to manufacture fuel blocks. In this case, instead of plant nutrients and/or growing media being introduced in the stage illustrated in Figure 2, a combustion promoting agent such as hydrogen peroxide may be introduced, together with other fuel components such as coal dust including anthracite dust, sawdust, wood chippings, charcoal or any other suitable hydrocarbon material. Pitch may also be used as an additive which also assists in binding the material.

Compression and dyhydration of the pulp material then takes place in the same way, with the exception that each block has a shorter axis to provide a greater exposed surface area for a given volume so as to promote combustion. Dehydration of the material is allowed to continue either naturally, or by suitable forced convection, until the moisture contents of the blocks is below 10%, at which level the blocks are ready for use.

Another useful source of the raw material is waste paper sludge from paper mills which contains the small fibres which are rejected as too small for papermaking.

It is believed that this method is particularly effective because of the shrinkage which occurs during drying of the cellulose or other fibrous material. This shrinkage causes a binding action which holds the blocks together.

Claims (21)

1. A method of making solid articles by forming a pulp or paste or saturated paper or like cellulose or other fibrous material comprising agitating the material in an excess quantity of water or aqueous solution of other chemicals, optionally adding to The.

pulp thus formed a composition including or comprising a surfactant and/or a foaming agent, and subsequently utilising the paste thus constituted in the production of moulded, extruded or otherwise shaped articles.

2. A method according to claim 1 and in which a foaming agent is added to the pulp or paste and in the subsequent forming processes the use of excess pressures for expressing the liquid or for obtaining the required shape is avoided so that the finished articles are lightweight and porous.

3. A method according to claim 1 and in which a foaming agent is omitted and the pulp compressed to form relatively dense solid articles when dried.

4. A method of producing blocks or pots for plant propagation purposes comprising the steps of forming.a pulp from paper or other biodegradable fibrous material in water or an aqueous solution, adding to the pulp a composition including a surfactant and/or a foaming agent, further agitating the pulp to ensure thorough mixing, draining excess liquid from the resulting mixture and forming this latter to shape in a mould or by extrusion and allowing itto dry.

5. A method according to claim 4 and in which one or more plant nutrients are incorporated in the final product, either by inclusion in the aqueous solution with which the initial pulp or paste is formed, or by inclusion in the composition added thereto, or by addition to the dried product by spraying or subsequent immersion.

6. A method according to claim 4 or claim 5 including the step of incorporating peat or other growing medium component in the pulp before or after admixture of the said composition including the surfactant and/or the foaming agent.

7. A method according to any of claims 4 to 6 in which the blocks are cylindrical in form with a recess in one end face, so that a seed or seedling can be equally spaced from the sidewall in all directions.

8. A method of producing fuel blocks comprising the steps of forming a pulp or paste from paper or other fibrous or cellulosic base material in water or an aqueous solution, optionally adding to the pulp a composition comprising or including a surfactant and/or a foaming agent and agitating the resulting mixture to ensure thorough dispersion of the constituents and draining the surplus liquid from the pulp thus formed, and forming the drained pulp into blocks or briquettes, a combustion promoting agent being added to the base material either in the aqueous solution or in the composition added to the pulp or subsequent to the initial draining stage.

9. A method according to claim 8 and in which the combustion promoting agent is an agent which releases oxygen on heating or in reaction with combustion products produced upon igniting the block.

10. A method according to claim 8 or claim 9 and in which pressure is applied to express surplus liquid from the pulp or paste during a drying stage.

11. A method according to any of claims 8 to 10 and in which a dry combustible material in the form of powder, flakes or granules is added to the pulp during or before the drying stage, and a binder, such as wood glue, cellulose paste or other binding agent is also incorporated before the material is dried.

12. A composition for use in the production of fuel blocks, comprising a surfactant combined with a foaming agent and a combustion promoting agent.

13. A composition according to claim 12 and in which the combustion promoting agent is hydrogen peroxide.

14. A combustible material comprising a bulk fibrous pulp material expanded by the addition of a foaming agent, formed into blocks and dried to a moisture content less than 20% by weight.

15. A combustible material formed from a bulk fibrous pulp material to which a surfactant has been added whilst in its saturated state, together with a combustion promoting agent, the material being formed into blocks and dried to a low moisture content.

16. A combustible material according to claim 15 in which the bulk fibrous material is further reinforced by the addition of a bonding agent.

17. A material according to any of claims 14 to 16 and in which the fibrous bulk pulp material is selected from paper, newsprint, cardboard and other board and paper derivatives, and waste paper sludge.

18. A combustible material according to any of claims 14to 17 and including material selected from coal, coal dust, coke, anthracite, charcoal (either in pieces or as a dust), wood, cotton rags and/or dehydrated vegetable residues and pitch.

19. A method of making solid articles substantially as hereinbefore particularly described and as illustrated in the accompanying drawings.

20. A solid article made by any of the methods hereinbefore particularly described.

21. Acombustible material substantially as hereinbefore particularly described.