FI94621C - Process for making a peat product - Google Patents

Description

- 94621

Method for making a peat product -

The invention relates to a method for producing a peat product according to the preamble of claim 1.

5 Compressed peat used as fuel is produced in the swamp in the open air. The peat is compressed and dried in the open air to a finished peat product. The quality of the peat, such as its moisture content, varies considerably depending on the weather conditions in which the product is produced in each case. Also, in terms of the composition of the peat mass, no similarity requirements can be expected from the peat produced by the milling machine as would be required for a peat product produced in factory-covered, covered premises. There are also a variety of other problems with peat handling in the swamp. It requires e.g. carrying out measures that would not be required at all during the factory production of the peat product.

Finnish Patent Publication No. 52590 discloses a method for processing raw peat by mechanical dewatering followed by screening. In the method, the raw peat is compressed to pre-dry the peat, after which the fibrous material and the peat dust are separated from this pre-dried peat mass. The coarse fibrous part remaining on the screen surface is pressed with a short thermal. after drying into bales for use as a soil improver. Peat dust is further divided into two parts, one for the production of coke and the other for the production of heat or electricity. Peat dust for the production of heat and electricity is dried and ground to a fine mass. Peat dust for coke production is treated with a colloid mill and a spiral press. The process described in U.S. Pat. No. 2,94621 thus produces conventional peat products.

German patent publication 382421 discloses a method in which peat is first heated at a temperature of 120 ° C, whereby a water-repellent layer is formed on the surface of the peat particle. Such peat can be used as such or mixed with other substances, for example as an insulating or building material.

German patent publication 287704 discloses 10 methods for making bricks from peat. The water separation of the peat is performed by pressing and then the peat is ground while stirring the binder and then the mass is shaped and allowed to dry in air.

The prior art methods described above are not able to provide a product suitable as a concrete aggregate in terms of compressive strength, size and shape.

Attempts have been made in concrete technology to find ways to improve the thermal insulation capacity of concrete and at the same time reduce its volume-20 weight. For this purpose, e.g. straw, the so-called Leca gravel and concrete and wood chips are made of so-called Porous concrete. The use of blast furnace slag as a concrete aggregate is also known. Blast furnace slag is a coal combustion waste from the manufacture of steel 25. It does not contain air, so its thermal insulation is poor.

Leca gravel refers to porous clay granules that have been fired to enclose air inside it. Leca gravel is hard but easily broken. Due to its fragility and uniformity, it does not function satisfactorily as a concrete aggregate.

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Siporex is made by heating high-temperature concrete mass to which wood chips have been added. When heated, water evaporates from the wood chips and the chips char or burn, creating gas-filled cavities in the pulp. Siporex is a 5 lighter Building Material and has a relatively good thermal insulation capacity.

The object of the invention is to provide a method for producing a peat product intended primarily as a concrete aggregate. The aim is precisely a method of manufacturing 10 peat products which is suitable for factory conditions, i.e. covered premises. The method according to the invention is mainly characterized by what is set forth in the characterizing part of claim 1.

Compared to the peat product produced in the open air, the peat product produced by the method according to the invention also meets the quality requirements for fuel much better. In addition, the method offers the possibility to produce peat products that are suitable for many uses 20 for which peat has not been used before.

By using the peat product produced by the method according to the invention, for example as a concrete aggregate, the thermal insulation capacity of the concrete is considerably improved and its bulk density is reduced. It also guarantees sufficient compressive strength for the concrete. The new peat product production method also makes it possible to omit the following work steps in the bog: drying of compressed peat * and transporting it to the openings, all open work and loading from the openings, turning and roughing of peat, and building 30 roads in the bog.

The peat peat solids consist of fossil and decaying plant parts as well as microscopically small 4,94621 rock particles. Natural peat contains a considerable amount of water and the air bound to it by decaying plant parts. When the peat mass is compressed, water is removed and a moist, water-mixed, adhesive binder containing hardening and binding aggregate particles encloses each peat particle, leaving air inside the peat particle. This adhesive binder acts like a concrete adhesive, i.e. a curable binder. When the peat is dried after pressing, it hardens into a piece with high compressive strength, the peat as if petrified into an air-containing fossil structure. Strength is based on aggregate particles bound to peat pores. Compressed peat contains a lot of air, which affects the thermal insulation of the substance. The air is encapsulated-15 in the peat down to the smallest peat particle. Compressed and dried peat repels water i.e. it is a hydrophobic substance. For the sake of clarity, it should be mentioned that milled peat and the so-called peat cakes absorb water into their pores.

This is due to the different treatment of peat.

The invention will now be described in more detail below with reference to the accompanying drawing, which schematically shows an apparatus for carrying out the method according to the invention.

The peat is lifted from the peat field using a peat lifting device 25 known per se, for example using a rotary-blade peat milling machine. The moist peat mass is transported to the factory and placed in the peat receiving silo 1. From the receiving silo 1, the peat mass is conveyed by a conveyor 2a • to a mixer 3, which is, for example, a screw mixer.

In the mixer 3, water and / or a binder, for example lime or peat ash, are added to the peat mass if necessary. In the figure, the water tank is marked with reference number 5 and the binder silo with reference number 6. The mass is therefore mixed. until homogeneous. The monitoring equipment in the mixer 3 preferably analyzes the water content and the amount of binder continuously. The mixed peat mass is fed to a press 4, which is shown below the mixer 3. The press 4 is preferably a hydraulic-5 press. The mat or rod-like, preferably continuous peat mass web pressed through the nozzles of the press 4 is fed to the drying oven 7 by means of a conveyor 2b. The drying oven is preferably continuous. In the drying oven 7, the peat mass is heated to dryness 10 and the drying is monitored by means of monitoring devices. The mass is dried very dry. As a result of pressing and drying, the peat hardens. After drying, the peat web is conveyed by a conveyor 2c to a crusher 8 and crushed into pieces. After crushing, the hot chopped peat 15 is conveyed by a conveyor 2d to be cooled in the cooling and storage heap 9. In the cooling and storage heap 9, the peat pieces are allowed to cool for about two days. As they cool, they continue to harden. The cooled and hardened peat is ready to be used as fuel.

20 In the production of peat concrete aggregate, the peat bodies are crushed after cooling, for example with a hammer, jaw or spindle crusher, into suitably sized peat granules. The peat granules are screened in the screening equipment into components of different sizes, i.e. fractions. In the preparation of the Be-25 ton alloy, the screen fractions are proportioned using a concrete technique and mixed with a reactive binder such as cement, lime or gypsum and water to form a peat concrete mass.

* Crushed peat produced as described above meets the quality requirements for 30 concrete aggregates. Peat is a water-repellent, hydrophobic substance, it contains air bound to itself. Crushed peat behaves like aggregate in a concrete mix. The aggregate can thus be • partially or completely replaced by crushed peat.

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Since peat is considerably lighter than aggregate, the use of peat as a aggregate provides a significant advantage. The volume weight of the finished peat concrete varies by about 1100 kg / m3. . about 250 kg / m3. Peat concrete insulates well with 5 heat and is an easy to process material. Peat concrete is well suited for the production of a wide range of products. It can also be made into an injectable, mass.

The invention is not limited to the above embodiment, but may be modified within the limits defined by the appended claims.

Claims (6)

1. A process for producing a peat product, wherein the peat is taken from the peat cover with a peat picking machine, the pulp is pressed into a mat-like or closed-like cloth, dried and crushed into peat pieces, characterized in that - before the peat is pressed it is transported to the factory and mixed. to a homogeneous peat mass in a mixer and - after being pressed and before crushed to peat pieces - the peat is heated to dry in a drying oven preferably in a continuous drying process, after which the peat is cooled. Method according to claim 1, characterized in that the peat of the factory is placed in a receiving silo, from which it is later transferred into said mixer. Method according to claim 1, characterized in that in the mixer the peat mass is supplied with water and / or binder such as, for example, lime and / or peat washing with stirring. 20 4. A method according to claim 1, characterized in that • after it has been dried and before it is cooled, the peat cloth is crushed to pieces of suitable size. 5. A method according to claim 1 or 4, characterized in that the peat pieces are crushed to 25 peat balls of suitable size after cooling, to be used as a body part in concrete. 6. A method according to claim 5, characterized in that the peat beads are screened in a manner known per se, and that the screened beads are proportioned using any 30 and known method in concrete technology for use as a concrete part in concrete. for a given purpose. • · Ml