DK141659B - Peat grains containing agglomerated peat particles as well as finely divided peat and process for making them. - Google Patents

Description

(11) SCRIPTURE 141659 DENMARK («> int.ci.3 c os f ti / οζ § (21) Note 209/72 (22) Filed on 1 ^ * Jan. 1972 (23) Life Day 1 ^ · * JSH 1972 (44) The annotation was made on the file of the May 19, May 1960

DIRECTORATE OF

PATENT AND TRADEMARKET SYSTEM <*> 7 £ * £ ΓΓ9η. S042 / 7 !, GE

(71) FISONS LIMITED, Harvest House, Felixstowe, Suffolk, GB.

(72) Inventor: Robert Wilson Palmer, The Lilacs, Thurmans Lane, Trlmley St. Mary, Ipswich, Suffolk, GB: Francis Neil Wilson, 66 Chelsworth Avenue, Ipswich, Suffolk, GB.

(74) Plenipotentiary in blessed treatment:

International Patent Bureau. (54) Peat grains containing agglomerated peat particles as well as finely divided peat and process for making them.

The present invention relates to a peat grain suitable for the production of fertilizers containing agglomerated peat particles. Furthermore, the invention relates to finely divided peat as well as to a method for producing such peat grain.

Previously, granular or granular fertilizers containing peat and fertilizer components have been prepared, especially for use as lawn fertilizers distributed from a spreader. However, the peat used in such agents has always been a dark peat containing a large amount of hard, gravelly particles and having a pH greater than 4.0, an ash content above 5% and a dry density of more than 0.20 g / ml . Such peat is usually known in England as semi-peat. Even ran the use of sphagnum peat (it is peat which contains larger, softer particles and often a large amount of long fibers and has a pH of less than 4.0, an ash content of less than 5% and a density in a dry state of less than 0.1 g / ml) would not be desirable. Thus, when the semi-turf peat used to make a peat grain was replaced by the same amount of commercially available sphagnum peat, the produced grains had essentially the same size but a different density than the semi-peat grain. . In an attempt to produce grains of substantially the same size and density from sphagnum peat, the sphagnum peat was ground to a smaller size than that used so far to obtain nearly the same particle size as the semi-peat it would replace (typically 1.5 to 3.0 mm). However, it was also found in this case that although the sphagnum peat grains were the same size, they had a different density and distribution rate than the semi-grass peat grains. When the formulation of the grain was adjusted to obtain a sphagnum peat grain of substantially the same size and density as the semi-grass peat, it was found that sphagnum peat grain still had a different distribution rate.

It has now been found that fertilizer grains having substantially the same distribution rates as semi-grass peat grains having substantially the same size and density can be prepared from sphagnum peat if the particle size of the sphagnum peat is much smaller than that previously available. The reason why the particle size of the peat should affect the distribution rate of a peat-containing grain cannot be explained and is to a high degree unexpected. The term "substantially the same" as used herein when comparing the size, density and / or distribution rate of the sphagnum peat-based grains with the same properties for the semi-peat-based grains denotes the properties of the sphagnum peat-based grain. is within plus or minus 10% of the mean value of the corresponding properties of the semi-peat-based grain. In addition, for the production of a grain of a given size and density, the amount of peat required is usually less for finely divided sphagnum peat than for semi-peat. This saving of peat used can be as much as 50%.

The term "sphagnum peat" is used in the present specification to claim a peat which satisfies at least two of the following criteria: a) it has a pH of less than 4.0, b) it has an ash content of less than 5 (c) it has a dry density of less than 0.1 g / ml.

In accordance with the above finding, the invention provides a peat grain containing agglomerated peat particles, characterized in that the majority of peat particles have a size of less than 0.5 mm, preferably an average particle size by weight of less than 3 and in that the peat is a sphagnum peat as defined above which may be ammoniated before the grain build-up, the grain possibly also containing a fertilizer material which may be formed in situ and preferably present in an amount of from 40 to 96 wt% of the total dry weight of the comet, and optionally also a filler such as sand, wherein the grain optionally has a coating containing an agrochemical or a fertilizer.

The peat used may, as mentioned above, be ammoniated or it may be subjected to another pretreatment before grannizing. This will have changed the nature of the original peat. That is, while the original peat may have been a sphagnum peat that would satisfy all of criteria (a), (b) and (c), it may appear that the form in which the peat is actually used does not satisfy one of the claims. As used herein, the term "sphagnum peat" encompasses, thus, pretreated peat.

It is also believed that this is the first time sphagnum peat has been ground or otherwise comminuted to such a small particle size as herein treated, and therefore, also according to the invention, finely divided peat for the production of a peat grain according to claim 1 is provided. is peculiar in that the majority, e.g. more than 90% of the particulate peat particles have a size of less than 0.5 mm, preferably an average particle size by weight of less than 0.25 mm, and the peat is a sphagnum peat as defined above.

The invention further provides a process for preparing the peat grain according to the invention, the process of which is characterized by granulating a material containing finely divided peat and optionally a filler such as sand and / or a fertilizer material which may be formed in situ. , eg. by shaking or stirring the material in the presence of water, preferably in an amount of from 10 to 50% of the dry weight of the material, and then drying the granulated product, preferably drying without relative movement between the grains, where the finely divided peat has a particle size of less preferably 0.5 mm, an average particle size by weight of less than 0.25 mm, and the peat is a sphagnum peat as defined above.

The term "particle size" used herein in the peat denotes the size of the largest dimension of the peat particles. The pH, the ash content and the dry density of the peat for the present use are measured in the following generally known manner before or after the peat is comminuted to the fine size for the present use: pH: A sample of peat (100% with a particle size of less than 9.5 mm) corresponding to 5 g of peat solids is stirred without drying after sampling in sufficient distilled water to give a total volume of 100 ml. The mixture is left at room temperature for 24 hours and the pH of the liquid is measured using glass electrodes. Ash content: A known amount of oven-dried peat is annealed at 650 ° C until constant weight, and the ash percentage is determined from the initial weight of the oven-dried peat used and the weight of the final residue.

Dry density: A sample (100 g) of peat is dried overnight in a drying oven at 105 ° C. The weight loss indicates the moisture content of the peat. The wet density is measured by weighing a known volume of the peat sample. The dry state density is then calculated from the expression: - Dry state density = wet state density) ^

Typical peat suitable for the present application has a pH in the range of 3.0 to 3.5, e.g. ca. 3.2, an ash content in the range of 1.0 to 2.5%, e.g. ca. 2.0% and a dry density of 0.05 to 0.095 g / ml, e.g. ca. 0.06 to 0.08 g / ml.

The sphagnum peat for the present application can be selected from a wide variety of such peat, although it will usually be desirable to use only one type of peat to obtain a uniform product. If desired, a mixture of sphagnum peat may be used. In addition, the peat may be subjected to appropriate forms of pretreatment prior to comminution, e.g. as mentioned, the peat can be ammonized with anmonia gas, in which case the peat, when used, will not satisfy all three of the above criteria (a), (b) and (c). Where the peat is ammonized, its arrow height may be increased to a value of e.g. ca. 5th

The peat is comminuted to the desired fine size by any suitable means, especially by grinding in e.g. a hammer mill, preferably using a rod sieve rather than using a round opening sieve, in a ball mill or in an air flow disintegrator. The peat should preferably have a moisture content of less than approx. 50% before grinding, although peat with higher initial water content can be used where special precautions are taken, e.g. by blowing hot air through the mill during grinding, or where other forms of comminution apparatus are used.

The comminution is carried out to produce a peat, the majority of the particles having a size of less than 0.5 mm, which is equivalent to using a 0.75 mm rod sieve in an hammer mill. The finely divided peat should preferably have an average particle size by weight of less than 0.25 mm, e.g. less than 0.15 mm, In a typical sample peat for the present application, 93% of the particles have a size less than 0.5 mm, 81% a size less than 0.25 ram and 58% a size less than 0.15 mm.

Since the peat is comminuted to such a small size, the presence of long fibers in the peat prior to comminution does not have a greater effect on the product unless present in large quantities, e.g. 20 volumes ^ or more. Therefore, it is possible in the invention to use peat that is not acceptable in some other applications.

In preparing the peat grains of the invention, the Peat Peat 5 is transferred to a granulating apparatus where it is shaken or stirred in the presence of water. If desired, fertilizer materials are also supplied to the granulator. The fertilizer constituents may be selected from any of the normally used and include the potassium and / or ammonium salts of phosphoric acid, sulfuric acid and / or nitric acid, urea, potassium chloride, urea / aldehyde condensation products and bone meal; trace elements such as copper sulphate, ferrous or ferric sulphate, sodium tetraborate, magnesium sulphate, potassium oilybdate and the like. These fertilizers can be pre-prepared or some may be formed in situ on the peat before or during granulation. Thus, the finely divided peat can be sprayed or shaken with phosphoric acid or nitric acid, and the treated peat can then be amaonized or treated with a base such as sodium or potassium hydroxide. When the ingredients are formed in situ, care must be taken to avoid excessive carbonization of the peat. Therefore, it is preferred that the temperature of the peat to form the components does not exceed 80 ° C, preferably not 50 ° C.

The fertilizer constituents can be added in a wide variety of conditions to produce a large number of products with different density and nutritional values; eg. For example, the fertilizer content may be from 40 to 6%, preferably 50 to 80%, of the dry medium weight. It is preferred that the peat content is from 10 to 30% by weight of dry peat based on the total dry weight of the agent, although in some cases the dry matter content of the peat may be as high as 40% or as low as 4%. '

If desired, other ingredients, such as dyes; calcium and / or magnesium carbonates, e.g. ground chalk or dolomitic limestone; fillers such as vermiculite, perlite, talc and sand which also affect the density of the final grain in a given formulation; as well as fungicides or pesticides are also mixed with the peat as an addition to or as a substitute for the fertilizer material. A binder can be used to aid in granulation when the finely divided peat is granulated alone. Suitable binders include clays, e.g. bentonite, ethyl acetate, starch, molasses gelatins, alginates and mixtures thereof.

The fertilizer and other ingredients can be mixed with the peat as dry ingredients, or some or all of the parts can be added as solutions or sludge, after which the mixture is fed to the granulator. Alternatively, some or all of the components may be added to the granulator as separate feeds for small batches.

In the granulation step, the finely divided peat and, where used, the fertilizer and other ingredients are shaken together in the presence of water. This water may be partially supplied as the water contained in the peat; using liquid constituents in the mixture fed to the granulator; using a separate liquid feed material for the granulator; by spraying water and / or water vapor onto the materials in the granulator; or by a combination of two or more of these methods. The optimum amount of water present in the mixture during granulation depends on a number of factors such as the desired grain size, the desired grain density, the composition of the mixture and the granulation temperature. However, it is usually desirable that the mixture to be granulated contains up to 80% by weight, e.g. from 10 to 50% by weight, water based on its dry weight.

The granulation is usually carried out in e.g. an Eirich mixer, a mixing auger or a rotary drum or pan granulator. The granulation is usually carried out at room temperature. The conditions in the granulator affect the size of the product grain and to a lesser extent its density. Therefore, the conditions can be varied in a known manner over a wide range to produce the desired product. Over-sized and under-sized bowls can be recycled to form part of the granulator feedstock.

The product from the granulator will usually contain approx. 10 to 40 wt.% Moisture and requires drying. The drying is preferably carried out without relative movement of the grains, so that the breakdown of the grains is limited to the least possible during this step. The drying is advantageously carried out on a moving belt or tray dryer, through or above which or which hot air is blown. The temperature during drying must not be so high as to cause any significant degradation of the constituents. The drying is therefore preferably carried out at less than 100 ° C, preferably at 70 to 110 ° C. Desirably, the drying is carried out to produce a product containing less than approx. 5% by weight, e.g. ca. 1.5% by weight, water. While the grain size remains almost the same during the drying step, the grain density decreases as water is removed from it. However, it will be clear that the final density of a grain at a given water content is first and foremost regulated by the formulation of the grain.

The peat grains of the invention have a size and density which can be adjusted as desired, although they will usually be in the range of 0.5 to 4 mm and 0.2 to 5 g / ml and the products are suitable for distribution. from a spreader instead of similar grains derived from semi-peat.

The peat grains of the invention have a wide variety of uses. Thus, where fertilizers and / or agrochemicals have been incorporated into the grains during their preparation, the grains can be applied directly to the soil. Where the grains contain only peat, they may be subjected to any subsequent treatment which will make them suitable for the intended use. Thus, a heat sensitive material, e.g. an agrochemical, advantageously added to the grains after they are formed, rather than during their preparation.

The invention is illustrated by the following examples in which all parts and percentages are by weight unless otherwise stated: 7 141659

Example 1 Raw sphagnum peat with a pH of £ 3.2, an ash content of 2.0% and a dry density of 0.09 g / ml was first ground to one coarse, particulate peat with particles of less than 9 mm. This coarse peat is then soldered into a hammer mill with a rod sieve with an aperture of 0.75 mm. The coarse peat brought to the hammer mill had a water content of 35%. The fine milled peat from the hammer mill had the following sieve analysis:

Sieve mesh width £ mm. % through particles 1.4 98 0.85 97.4 0.5 92.7 0.25 59.4 0.15 25.8

The finely ground peat was then mixed / down with the following ingredients: Peat (dry weight) 16.0 parts

Monoammonium phosphate 8.1 parts

Potassium sulphate 8.0 parts

Ammonium sulfate 32.4 parts

Urea 14.0 parts

Sand 19.5 parts in an Eirich mixer with 10 parts water sprayed on the shaken mixture.

After 4 minutes of granulation at room temperature, no grains were formed having an average diameter of 1.3 am, a density of 0.61 g / ml and a water content of 28.5% w / w. The moist granules were spread on a moving belt dryer over which air is blown at 86 ° C. After 35 minutes, the moisture content of the grains was reduced to 2%, giving hard, gravelly grains with an average diameter of 1.3 mm, a density of 0.4 g / ml and a fertilizer content of 14% N, 4% P205 and 4% K20 by weight. These grains were distributed from a spreader at substantially the same rate as at substantially the same size and density made from a semi-turf peat with a pH of 4.9, a ash content of 6.5% and a dry density of 0.12 g / ml, The semi-peat grains contained 35% by weight of peat compared to a peat content of 16% in the grains of the invention.

By comparison, the fine comminution of the peat was allowed and grains were prepared using the coarse sphagnum peat, which had a sieve analysis where 80% of the particles had a size less than 9 ram, 55% a size over 3.2 mm and only 11% a size less than 0.5 mm. Direct replacement of the semi-turf peat with this coarse sph ^ num peat yielded a diameter of 1.3 mm and a density of 0.2 g / ml. These are spread at a rate of approx. 40% of semi-grass

Claims (2)

1At659 8 Peat Grain Speed. The formulation was then adjusted to yield grains of substantially the same size and density as the semi-peat grains by reducing the peat content of the grains. However, in this case, the spread rate was only 45% of the semi-grass grains. For further comparison, the above method was prepared using sphagnum peat ground to ca. the same size as the half-grass turf, i.e. 100% with a size less than 3 mm. The granulation conditions and formulation were adjusted to obtain a grain of the same size and density as the semi-grass peat. In this case, the peat content was 16% and the spread rate was only 48% of the semi-grass grains. Example 2 The procedure of Example 1 was repeated on a commercial scale over a period of several weeks using sphagnum peat from two different sources. Of course, while the fertilizer constituents were kept at the same levels as in Example 1, it was necessary to vary the peat and sand content to about the nominal values of 16 and 19.5 L, respectively, to compensate for density variations in the peat used. The sphagnum peat used had the following characteristic properties: pH_Aske content_ Dry density g / ml. Peat A 3.0-3.2 1.8-2.2 0.096-0.112 Peat B 3.0-3.2 1.5-2.0 0.065-0.088 The grains produced from these peat were essentially the same size and density and essentially the same spreading rate as a semi-grass peat grain. 1. Peat grains containing agglomerated peat particles, characterized in that most of the peat particles have a size of less than 0.5 mm, preferably an average particle size by weight of less than 0.25 mm, and in that the peat is a sphagnum peat as defined in the description, which may be ammoniated before the grain build-up, the grain possibly also containing a fertilizer material which may be formed in situ and preferably present in an amount of from 40 to 96% by weight of the total dry weight of the grain, and optionally also a filler. , such as sand, wherein the grain optionally has a coating containing an agrochemical or a fertilizer. A finely divided peat for making a peat grain according to claim 1, characterized in -