CN1034148A - Rubbish is transformed into a kind of method of grain shape material - Google Patents

Abstract

A method of converting waste into a granular material characterized by Yu, by shredding garbage, is actually shredding that removes all the metal pieces Garbage and at least one powdery ore containing free or combined calcium oxide To mix substances to prepare a homogeneous mixture; to form this mixture into a compressed form formula; the compressed body is heated, dried, and hardened; the crushed dry hardened compressed bodies, made of finely divided mixtures of granular particles and fibers Material; this material is agglomerated to produce granular shapes. this grain Granules can be used to produce building materials.

Description

The present invention relates to a method of converting waste into a granular form material. More specifically, the method converts waste, especially domestic waste, into hard particles that are both corrosion-resistant and insoluble in water, which can be used in the production of building materials such as bricks or as an aggregate for the preparation of concrete.

This problem is notoriously difficult to solve due to the need to prevent pollution and other nuisances while removing ever-increasing amounts of litter and waste.

In order to provide an acceptable solution to these problems, it has been proposed to convert previously shredded waste from which any metals it may contain may be converted into a solid of various forms and sizes which may be used as a construction material.

For example, French Patent No. 2098777 describes the preparation of hard solid blocks that can be used as building materials or filling materials: a metal silicate is added to a pile of unsorted comminuted waste, and the This pile of waste is compressed under high pressure into block form, and finally the block is hardened by heating either at room temperature or at a temperature of, say, 80-200°C.

French Patent Application No. 2286116 describes a method for preparing cylindrical aggregates from demetallized, dry and comminuted waste to replace natural gravel in concrete production. According to an example of carrying out the method, the rubbish pulverized powder is combined with an anti-rot protection agent such as metal silicate or furfural, a binder such as a synthetic resin, a soluble bitumen or quicklime, ore slag and a binder The hardening catalyst is mixed to make a thick paste, which is pressed into a cylindrical compressed body by compression molding, and finally these compressed bodies are heated at a temperature not exceeding 200°C for hardening.

The methods according to the prior art mentioned in the above-mentioned documents are not completely satisfactory, mainly because these methods cannot guarantee that the resulting solid (with good mechanical properties) has high biological and chemical inertness, and at the same time cannot guarantee The solubility in water is zero, and these properties are very much needed in the use as a building material.

The purpose of the invention is to convert a large amount of rubbish into hard granules which are both anti-corrosion and practically insoluble in water. The garbage used is not sorted, and only the metal components that may be contained in the garbage, especially metallic iron, are removed by known methods and then pulverized. For this purpose, the method according to the invention has the features stated in claim 1 .

Therefore, according to the invention, the method is based on the following processes, the thermal treatment of compacted bodies (produced by granulation under pressure of a homogeneous mixture mainly composed of comminuted waste and calcium oxide-containing mineral material), the These ingredients are ground or pulverized to form a fine powder consisting of particles and fibers, which is finally agglomerated into granular form.

It has been surprisingly found that this new combination of operations yields particles with high mechanical resistance, high chemical inertness, high biological inertness, and almost zero solubility in water, so that these particles have the potential to be used in many different applications. a useful use, especially for the production of construction materials, without any pollution and other nuisances.

Minerals containing free or combined calcium oxide may be selected from materials such as quicklime, calcite, limestone and clay.

In the mixture of pulverized waste and calcium oxide-containing minerals, the waste content is preferably 90-95% by weight and the mineral content is 5-10% by weight.

Furthermore, comminuted refuse or a mixture of ground refuse and calcium oxide-containing minerals can be mixed with various fillers, especially minerals containing free or combined calcium and magnesium carbonates, such as dolomite.

The various operations for carrying out the method of the invention may be carried out in any suitable way, in particular for waste disposal using known techniques and common equipment.

In particular, in order to obtain rubbish that is practically free of metal components, it is possible to use the usual sorting and sieving operations of rubbish or waste in collection bins, in order to separate objects that can be recycled and/or reused, especially large pieces Metal.

Thereafter, the rubbish may be comminuted and mixed simultaneously or separately in order to obtain a homogeneous powdery mixture practically free of metallic materials (especially iron) and, where possible, with one or more In particular the sorting operation of ferrous fragments is combined. For example, the primary coarse crushing of sorted waste, so that the average size of the fragments is about 50 mm, is carried out before or after magnetic sorting to remove iron particles and other ferromagnetic materials. A second comminution is then carried out using, for example, rotary hammers, pulverizers or shredders to reduce the waste to fine particles in the form of granules or fibers with a maximum diameter of less than 20 mm.

The mixing operation of the bulk crushed waste and calcium oxide-containing minerals may also use any suitable technique and equipment, in particular the use of batchers and automatic mixers which may operate continuously or intermittently.

Compressed bodies prepared from a mixture of comminuted waste and calcium oxide-containing minerals, which can be produced at a pressure of 150-900 bar using a rotary granulation unit (e.g. for the production of pelleted animal feed) equipped with rollers and dies Granules, made into, for example, a cylindrical compressed body with a length of 5-60 mm and a diameter of 2-20 mm.

The heat treatment of the compressed body is preferably carried out by passing the compressed body axially through a tubular rotary kiln with a horizontal axis of rotation, said kiln being heated by hot air and having spiral walls inside to ensure the circulation of the compressed body. In particular, it is possible to use a kiln or furnace through which a flow of hot air, heated with burners to a temperature in the range of 250-400° C., flows in the same direction as that of the compressed body.

The effect of this treatment is to reduce the water content of the compact to eg 5% by weight and to increase the hardness of the compact by carbonization of the calcium oxide into calcium carbonate. After drying and hardening, the compressed body can be comminuted by any suitable method, in particular, using a removable hammer mill with a screen through which the comminuted material passes. The resulting material contains a certain proportion of fibrous material (from the original waste such as textiles, plastics and cellulose materials) and a certain proportion of crushed minerals (such as glass, limestone, etc. or organic matter from the waste) Subdivided material of the resulting granulated particles. The length of the fibrous material is adjusted so that most of the fiber lengths are within a given range, preferably 0.1- between 30 mm. For example, when crushing compressed bodies, the length of fibers can be adjusted by selecting a suitable fineness of the mill screen, such as 1-4 mm, and in general, the size of the subdivided materials can be adjusted.

Agglomeration of a subdivided group of materials (obtained by pulverizing or grinding compacts) into granules may be by any suitable method, e.g. one method may use drum and disc agglomerators, or Both devices can be used in combination.

Preferably at least one binder and at least one mineral filler are added to the finely divided material prior to the agglomeration treatment.

As a binder, hydraulic cement or calcined ash or ferrosilicon powder from cleaning sludge is preferably used. As mineral fillers, for example, calcium carbonate, powdered limestone, hydraulic lime, ashes from facilities for recycling construction materials, and ash from other industrial facilities can be used.

In order to agglomerate finely divided material or a mixture of finely divided material, binder and final filler, it is preferable to add a certain amount of water.

For example, binder, possible mineral fillers and water can be added in a homogeneous mixture to the material consisting of granular particles and fibers in a mixer placed before the agglomeration device. A homogeneous mixture can also be formed in an agglomeration treatment unit. As an option, it is also possible to add binders and final mineral fillers to the subdivided material consisting of granular particles and fibers, in the mixer (located before the agglomeration treatment device), to form a primary homogeneous mixture, and in the adjacent Sufficient water is added to the polytreater to agglomerate the mixture.

According to another stool ┍Jiaojiao: Mother Mu  Paddle Fu  Chexia Liang coated with 甾盍 shrimp slough fresh Jun? The water is mixed in the mixer (located before the granulation device), the mixture thus obtained is mixed with the granular granules and The mixture of fibers is simultaneously introduced into the pelletizing unit. According to another modification of the method, a homogeneous mixture of subdivided material (consisting of granular particles and fibers) with binders and mineral fillers can be prepared in a drum granulator that also serves as a mixer, and then The above amount of water was added to agglomerate the mixture into granular form. The drum operates in the form of pellets. The resulting granules are then transferred to a plate granulator where the agglomeration process ends. For example, a homogeneous mixture of binder and mineral filler, or even a finely divided material consisting of binder, mineral filler and fibers of granulated granules, can be supplied to the granulation unit to enlarge the primary granulation and produce a A particle consisting of an inner core and an outer shell of composition different from the inner core. This special treatment results in particles with an outer shell that is harder than the inner core.

Preferably, the particles obtained from the agglomeration treatment are subjected to a further hardening treatment. For example, hardening (the conditions of which depend on the properties of the materials constituting the particles, mainly on the properties of the binder used) includes at least one operation, that is, the application of high pressure, heat or steam to the particles, or a combination of the above three Two types of factors play a role. Obviously, the above operation can be combined with another operation to obtain particles with a desired structure, especially a composite structure.

Example 1

952 parts by weight of a primary homogeneous mixture were prepared from comminuted or pulverized domestic waste. The moisture content of the mixture was 30% by weight (resulting from the removal of 48 parts by weight of metal lumps from 1000 parts by weight of domestic waste), and the mixture contained 50 parts by weight of quicklime and 5 parts by weight of calcium carbonate. The mixture is compressed at a pressure of 150 bar in a compressor with a rotating shaft and a die to produce a cylindrical compressed body with a diameter of 8 mm and variable length (between 10-20 mm). The compressed body passes through a rotating tubular furnace or kiln with a horizontal axis, where it is dried and hardened. The hot air flow at a temperature of 250°C passes through the heating furnace or kiln, and the time for the compressed body to pass through the kiln is 30 minutes.

The compact obtained in this way contained 720 parts by weight and had a moisture content of slightly less than 1% by weight.

These compacts are pulverized into a fine powder in a hammer mill equipped with a 2 mm diameter screen to obtain a finely divided material consisting of granulated particles and fibers with a variable length of 0.1-30 mm.

A homogeneous mixture of finely divided materials, hydraulic cement and silica powder was prepared in a mixer in the following proportions (parts by weight).

Fine trash material: 2

Calcareous Rock Powder: 1

Hydraulic cement: 1

A certain amount of water (70 parts by weight of water was added to 100 parts by weight of the above mixture) was added to the above mixture to form a paste. The tumble mixer is then used as a granulation drum to make the paste into spherical granules. The resulting granules are transferred to a granulation pan. While the granulating disc is rotating, a dry homogeneous mixture of cement and lime powder in equal weight ratios (approximately 40 parts of this mixture to 100 parts of the initially finely divided material) is added. In this way, the diameter of the granules increases continuously, the granules reaching the desired final diameter fall out of the pan, and the final granules are dried in air at ambient and normal temperature conditions for several days. The particles thus obtained have a diameter of 2-15 mm. The overall density is 750kg/m ³ and the moisture content is 30% by weight. Each particle has a spherical portion or outer shell that is harder and less water soluble than its inner core.

Example 2

As described in the first part of Example 1, domestic waste was converted into an inert, hardly soluble finely divided material consisting of granular particles and fibers. The finely divided material is then granulated in a granulation pan to produce a material in the form of spherical granules. The method used was similar to that of Example 1, but the pelletizing disk was used with two rims instead of one rim, ie an annular area surrounding the central part of the pelletizing disk.

The composition of the initial mixture added to the central part of the granulation disk is as follows (parts by weight):

Fine trash material: 10

Big Hard Cement: 7

The mixture was poured into a granulation pan and the same proportion of water as in Example 1 was added in the form of spraying the mixture in the granulation pan. The diameter of the particles entering the annular granulation zone through the rim of the central circular granulation section is different, between 7-11 mm. In the annular granulation zone, the uniform mixture of Portland cement and lime powder is sprinkled on the particles, and the composition of Portland cement and lime powder in the mixture is as follows (parts by weight):

Portland Cement: 1

Lime powder: 1

The mixture was used in an amount of 50 parts by weight to 100 parts by weight of finely divided material (consisting of granulated particles and fibers of garbage), agglomerated by spraying water while adding the mixture.

The resulting pellets, with a diameter between 8 and 12 mm, pass over the outer rim of the annular granulation zone and are exposed to ambient temperature (at normal humidity) for final hardening.

This results in pellets with a harder outer shell than the central part, with an overall density of material in the range of 700kg/ ^m3 .

Example 3

The granules obtained as described in Example 1 were used as aggregate in the preparation of cement. For this purpose, the granules were mixed with a dilute mortar of cement and water corresponding to an amount of cement of 400 kg per cubic meter of cement and granule mixture, with a water/cement weight ratio of 0.57.

After 36 days of hardening, the resulting concrete block has a density of 1500kg/m ³ and mechanical properties as follows:

Bending traction is N/mm ² : 1.78

Compression resistance (cubic) N/mm ² : 7.17

Thermal insulation coefficient w/m.k: 0.55

Example 4

The granule prepared according to the method described in Example 1 is mixed with cement, water is added, and the mixture is vibrated and compressed in a mold to prepare bricks. The cement consumption is 300 kilograms per cubic meter of mixture. At ambient temperature, after 32 days of drying and hardening, the water content (weight) is about 20% relative to the weight of the cement. The specific gravity of the obtained brick is 1650kg/m ³ , the compression resistance is 4.3N/mm ² , and the thermal insulation coefficient is 0.45w /mk, can be used to build walls with good thermal insulation properties.

Claims (18)

1. A method of converting refuse into a granular material, characterized in that it consists of comminuting comminuted refuse, in fact from which all metal objects have been removed, mixed with at least one powdered mineral containing calcium oxide in free or combined form Prepare a homogeneous mixture; make this mixture into a compact form; the compact is heated to dry and harden; crush the dry and hardened compact to make a very fine material composed of a mixture of granular particles and fibers; this material is made by agglomeration Granular form. 2. The method according to claim 1, characterized in that the fiber length of the finely divided material is adjusted during and/or after comminution of the compacted body. 3. The method according to claim 2, characterized in that said operation of adjusting the length of the fibers after crushing is a screening operation. 4. The method according to one of claims 1 to 3, characterized in that comminution of the compressed body and/or subsequent adjustment of the fiber length is carried out to a fiber length in the range of 0.1-30 mm. 5. The method according to any one of claims 1 to 4, characterized in that, using a drum-type or disc-type agglomeration device, or using . 6. The method as claimed in one of claims 1 to 5, characterized in that at least one binder is added to the finely divided material to form a homogeneous mixture prior to the agglomeration treatment. 7. The method according to claim 6, characterized in that the binder is selected from the group consisting of hydraulic cement, calcined ash of cleaning sludge and powdered ferrosilicon. 8. The method as claimed in claim 6, characterized in that at least one pulverulent mineral filler is also added to the finely divided material. 9. The method according to claim 8, characterized in that the mineral filler is selected from the group consisting of calcium carbonate, calcareous rock flour, hydraulic lime, clay and dust generated in recycling construction material installations. 10. according to the described method of one of claim 6 to 9, it is characterized in that, in the subdivided material that is made up of granular grain and fiber, the total content of the binding agent that adds and mineral filler is per cubic meter of final material ( Dry state) 300-1800 kg. 11. The method according to any one of claims 1 to 10, characterized in that sufficient finely divided material or a mixture of finely divided material, binder and possible mineral fillers is added to make this material or This mixture agglomerates a certain amount of water. 12. The method as claimed in one of claims 1 to 11, characterized in that binder, mineral filler and water are added to the inert finely divided material in a mixer upstream of the agglomeration treatment device. 13. The method as claimed in one of claims 1 to 11, characterized in that the addition of binder and water and possibly mineral material to the finely divided material takes place in a device for agglomeration. 14. The method according to one of claims 1 to 12, characterized in that the addition of binders and mineral fillers (thus forming the first dry mixture) to the subdivided material composed of granular particles and fibers is carried out in the vicinity in a mixer upstream of the agglomeration unit, where said quantity of water is added to the first mixture. 15. The method according to one of claims 1 to 12, characterized in that a mixture of subdivided materials, binders and possible mineral fillers is prepared and the mixture is made into granular form (the above two This operation is carried out in the same mixing-granulating device). The granules thus obtained are placed in a granulation pan, and a powdery binder or mixture of powdery binders and mineral fillers are added to produce granules consisting of a central part and surrounded by a composition different from that of the central part. 16. The method according to any one of claims 1 to 12, characterized in that the binding agent and the mineral filler are mixed with the above-mentioned amount of water in a mixer upstream of the agglomeration treatment device, and the subdivided material is then mixed with the The mixture obtained from the mixer is fed into an agglomeration treatment device to agglomerate to produce granules consisting of a central part and an outer shell of a different composition from the central part. 17. The method according to any one of claims 1 to 16, characterized in that the granules obtained after the above-mentioned agglomeration treatment are hardened. 18. The method of claim 16, wherein said hardening treatment comprises at least one operation, ie, subjecting the particles to high pressure, heating or steaming, or a combination of two of these three factors.