AU651079B2 - Treatment of carbonaceous material - Google Patents

Description

WO 91/09820 PCT/A U90/00602 TREATMENT OF CARBONACEOUS MATERIAL TECHNICAL FIELD This invention provides a novel method for the treatment of carbonaceous material to modify its structure.

The resulting modified material finds particular, but not exclusive, application as a fertilizer and/or soil conditioner.

The extensive use of chemical fertilizers over the last 50 years has not been without associated problems. Apart from being an expensive procedure, chemically fertilized soils gradually suffer degradation and surface runoff and groundwater sources in the vicinity are contaminated by excess fertilizer application.

WO 91/09820 PCT/AU90/00602 2 It is generally agreed that the preferred method of farming involves the maintenance of the organic content of the soil by mulching or ploughing in crop wastes. This environmentally friendly inethod of land-use has the advantage of helping to maintain soil structure, ensuring a slow release of nutrients, and maintaining soil moisture levels; thus it also reduces water usage. However, this technique has a limited application because of the lack of quantities of suitable carbonaceous mulch.

Lignite in its natural form has some of the required attributes such as moisture holding ability, soil forming ability and it maintains a capacity to slow the release of nutrients. However, it is generally unsuitable for mulching alone because it lacks various trace elements and is too easily oxidised to a dust. Ground lignite also tends to reduce soil porosity, and it can also be a dangerous substance to transport.

The present invention enables natural lignite to be treated so as to produce a modified material more amenable to use as a fertilizer and/or soil conditioner.

Although the invention has particular application to the treatment of lignite it may also be applied to other naturally occurring carbonaceous materials such as peat, subbituminous coal or sewage sludge. Moreover, although the resulting modified carbonaceous material may be used as a fertilizer or soil improver it may have other uses such as in the production of activated carbon.

DISCLOSURE OF THE INVENTION The invention broadly provides a method of modifying a carbonaceous material by subjecting that material to the action of a bioactive agent.

Preferably, the bioactive agent comprises bioactive micro-organisms and enzymes of a kind found in natural compost.

More particularly, the bioactive agent may comprise Actinomycetes, streptomyces, bacillus sp, pseudomonas etc and WO 91/09820 PCT/AU90/00602 3 enzymes capable of assisting in the degradation of the carbonaceous material and the release of stearic acids and nutrients.

The carbonaceous material may be lignite and the modified material may be produced for use as a fertilizer and/or soil conditioner.

The invention further provides a method of producing a fertilizer and/or soil conditioner comprising the steps of subjecting a carbonaceous material to the action of a bioactive agent and adding a binding medium to the resulting modified carbonaceous material.

The carbonaceous material may be lignite and the bioactive agent may comprise bioactive organisms and enzymes of a kind found in natural compost, such as Actinomyectes and enzymes. Some such agents are commercially available in various forms but specific cultures may be prepared for special applications.

The modified carbonaceous material and binding medium may be extruded, moulded, cast, rolled or otherwise formed into structurally coherent pieces or articles. It may, for example, be formed into pellets for large scale farming applications or formed into sheets, strips, troughs, dishes,pots, boxes or other shapes suitable for horticultural purposes.

Preferably, the binding medium is comprised of cellulosic fibres. It may, for example, be comprised of paper fibres.

The invention also extends to a modified carbonaceous material produced by subjecting a naturally occurring ca2rbonaceous material to the action of a bioactive agent.

The invention further extends to a fertilizer and/or soil conditioner comprising a mixture of binding medium and a modified carbonaceous material resulting from the action of a bioactive agent on a naturally occurring carbonaceous material, for example lignite.

WO 91/09820 PCY/AU9000602 4 BEST MODES OF CARRYING OUT THE INVENTION In a typical process carried out in accordance with the present invention, lignite is ground to about minus 1/8" mesh and water added to form a slurry in a batch tank. This slurry is then treated with suitable reagents for example CaCo3 to increase its Ph. The slurry is then inoculated with bioactive microorganisms and enzymes commonly found in natural compost; (between <,001% and 0.01% by weight of the active ingredients will generally be required). The mixture is gently stirred for 8 hours. The bioactive agents may include microbial flora such as Actinomycetes or other selectively cultivated and adapted bacteria.

The pre-treatment of the lignite as described significantly alters its physical and chemical chaxacteristics.

It binds together more readily, re-wets more quickly, and more rapidly transforms into a true soil. The inherent problems of pore binding and the retention of moisture below a value associated with untreated lignite are largely overcome.

At this stage other nutrients are added to make up the recognised deficiencies in lignite as a growing medium such as nitrogen, phosphorous and potassium bearing compounds.

Various rzttios of nitrogenous, phosphorous and potassium compounds may be required tor different applications but if the material is to be used as a growing medium these constituents would comprise no more than 10% by weight. However, higher proportions could be incorporated if the material is to be used as a fertilizer only, in this case the fibre ratios would change. The high proportion of carbonaceous material to nutrients results in a product that releases the nutrients on demand, i.e. a slow release fertilizer. The nutrients remain bound to the carbonaceous material.

The resulting carbon-rich product could be dried and used as a fertilizer and soil improver at this stage but has been found to be rather friable. Thus, in the preferred process, pulped fibrous material such as waste paper in the form of a ra'zher thick slurry or as a dry 'flock' is added to WO 91/09820 PCT/AU90/100602 5 the treated lignite to bind it into a material that can be produced in a pelletized form suitable for large scale farming applications or moulded, cast or rolled into various shapes suitable for other horticultural applications. It has been found that as little as 10% by weight of paper fibre is sufficient as a binder but other proportions may be required for specific applications. Binders such as clay or zeolite can also be incorporated to enhance the product density and pellet strength but the use of cellulose fiber maintains the highest carbon content of the product.

The cellulose fibre binder can be produced by pulping waste paper with water or by a process of 'beating' to produce a paper 'flock'. If the product is to be pelletized, water usage should be kept to a minimum since the moisture content has to be reduced either by natural or forced drying to about in the finished product but in other cases the product can be pumped or sprayed in a slurry form.

The resulting 'dough' can be pelletized, extruded in various forms or rolled flat. Increased pressure will increase the density of the final product and thus will vary the rapidity of its breakdown to soil elements on re-wetting, increasing the slow release characteristics of the final product. Mechanical processes will speed the drying process to achieve a moisture content of between 20% and 35% again depending on the lignite type.

INDUSTRIAL APPLICATION The invention has particular application to the production of fertilizers and soil conditioners.

Since the product contains nearly 100% carbonaceous material of varying density and can be manufactured with a high porosity and with added nutrients, it is also suitable for other uses such as the basis for the production of a bioactive material designed to treat contaminated water and soils, the bacterial cultures incorporated being cultured for various environmental contaminants such as oils and phenols. For WO 91/09820 PCT/AU90/00602 6 example, the material is naturally oeleophilic and can be made with a density so low that the material will float, and can be spread across an oil slick, where bacterial action can commence to break down the oil slick.

Claims (10)

1. A method of modifying a carbonaceous material that has undergone at least some coalification comprising subjecting the said carbonaceous material to the action of a bioactive agent comprising microorganisms and enzymes of a kind found in natural compost capable of degrading that material.

2. A method as claimed in claim 1, wherein the carbonaceous material is lignite and the bioactive agent comprises Actinomycetes and enzymes capable of degrading lignite.

3. A method of producing a carbonaceous material product, comprising the steps of subjecting a carbonaceous material that has undergone coalification to the action of a bioactive agent comprising microorganisms and enzymes of a kind found in natural compost capable of degrading that material and adding a binding medium to the resulting modified carbonaceous material.

4. A method as claimed in claim 3, wherein the carbonaceous material is lignite and the bioactive agent comprises Actinomycetes and enzymes capable of degrading lignite.

A method as claimed in claim 3 or claim 4, wherein the binding medium is comprised of cellulosic fibres.

6. A method as claimed in claim 5, wherein the cellulosic fibres are paper fibres.

7. A method as claimed in any one of claims 3 to 6, wherein the modified carbonaceous material and binding medium is formed into pellets.

8. A fertilizer and/or soil conditioner comprising a mixture of a binding medium and a modified carbonaceous material resulting from the action of a bioactive agent on a naturally occurring carbonaceous material according to any one of claims 3 to 7. 8

9. A fertilizer and/or soil conditioner comprising a binding medium comprised of cellulosic fibres and a modified carbonaceous material resulting from the action of Actinomycetes and enzymes on lignite according to claim 2. A method of treatment of an oil slick comprising the step of applying a modified carbonaceous material produced according to any one of the methods of claims 1 to 7. DATED THIS 28TH DAY OF MARCH 1994 BRUCE ROY THOMPSON By Its Patent Attorneys GRIFFITH HACK CO Fellows Institute of Patent Attorneys of Australia .4' 0r I. I I )C' I= i. INTERNATIONAL SEARCH REPORT International Application No. PCT/AU 90/00602 I. CLASSIFICATION OF SUBJECT MATTR (if several classification symbols apply, indicate all) 6 According to International Patent Classification (IPC) or to both National Classification and IPC Int. C. 5 C05F 11/02, 11/08, C09K 17/00 II. FIELDS SEARED Minimum Documentation Searched 7 SClassificacion System I Classification Symbols IPC C05F 11/02, 11/08, C09K 17/00 Documentation Searched other than Minimum Documentation to the Extent that such Documents are Included in the Fields Searched 8 AU: IPCas above III. DOCUMENS CONSIERED TO BE RELEVANT 9 Category* I Citation of Document, with indication 2where appropriate, Relevant to I of the relevant passages Claim No 13 X AU,A, 33019/78 (RHMEISCE BRAUNKOHE WE E AG) 6 February 1978 (06.08.78). See entire document 4, 8, 9) X,Y U,A, 3607212 (NETIESEIM et al) 21 September 1971 (21.09.71) column 1, lines 11-17 4, 6, 9) 9-10) Y US,A, 4119429 (LOVEESS)

10 October 1978 (10.10.78). See claim 1, 7 9-10) X Derwent Abstract Accession no. 85-131738/22, class P1l P13 JP,A, 60-069184 (KOBAYASHIC) 7 June 1983 (07.06.83) 4, 6, 9) X Derwent Abstract Accessicn no. 29143 K/12, class C04, SU 927789 (ASUKR TIERMDPHYS) 15 May 1982 (15.05.82) b. 6, 9) X EP,A, 223661 (FERTIL FRANCE AGRO) 27 May 1987 (27.05.67) claim 1 (1) Special categories of cited documents: 10 Later document published after the international filing date or priority date document defining the general state of the and not in conflict with the application but art which is not considered to be of cited to understand the principle or theory particular relevance underlying the invention earlier document but published on or document of particular relevance; the after the international filing date claimed invention cannot be considered novel document which may throw doubts on priority or cannot be considered to involve an claim(s) or which is cited to establish the inventive step publication date of another citation or document of particular relevance; the other special reason (as specified) claimed invention cannot be considered to document referring to an oral disclosure, involve an inventive step when the document use, exhibition or other means is combined vith one or more other such document published prior to the documents, such combination being obvious to international filing date but later than a person skilled in the art. the priority date claimed document member of the same patent family IV. GERTIICATION I Date of the Actual Completion of the Date of Mailing of this International I International Search I Search Report 22 March 1990 (22.03.90) C p. I SInternational Searching Authority Signatre of Authorized Offic Australian Patent Office I B BUJRE Form PCT/ISA/210 (second sheet) (January 1985) International Appi'cation No. PCT/AU 90/00602 URHnE INFORMTION CONTINUED FROM THE SECOND SHEET I II OM ERVATIONS WHERE CERTAIN CLAIMS WERE FOUND UNSEARHABE 1 This international search report has not been established in respect of certain claims under Article 17(2)(a) for the following reasons: 1. Claim numbers because they relate to subject matter not required to be searched by this Authority, namely: Isearched by this Authority, namely: 2. Claim numbers because they relate to parts of the international application that do comply with the prescribed requirements to such an extent that no meaningful international search can be carried out, specifically: 3. Claim numbers because they are dependent claims and are not drafted in accordance with the second and third sentences of PCT Rule 6.4 OBSERVATIONS VHERE UNITY OF INVENTION IS LACKING 2 This International Searching Authority found multiple inventions in this international application as follows: 1. As all required additional search fees were timely paid by the ai search report covers all searchable claims of the international 2. As only some of the required additional search fees were timely international search report covers only those claims of the inte which fees were paid, specifically claims: 3. No required additional search fees were timely paid by the appli I international search report is restricted to the invention first it is covered by claim numbers: I 4. As all searchable claims could be searched without effort justif the International Searching Authority did not invite payment of IRemark on Protest I The additional search fees were accompanied by applicant's protest. No protest accompanied the payment of additional search fees. pplicant, this international ipplication. paid by the applicant, this rnational application for cant. Consequently, this mentioned in the claims; ying an additional fee, any additional fee. Form PCT/ISA/210 (supplemental sheet (January 1985) ANNEX T THE IN T ERNATIONAL SEARCH REPORT ON INErnATIONAL APPLICATION NO. PCT/AU 90/00602 This Annex lists the known publication level patent family nxmbers relating to the patent documents cited in the above-ntioned international search report. The Australian Patent Office is in no way liable for these particulars which are merely given for the purpose of information. Patent Document Cited in Search Patent Family Members Report US 3607212 DE 1667799 US 4119429 GB 1562556 EP 223661 EP 223662 FR 2588892 FR 2592892 END OF ANNEX