SE459236B - PROCEDURE FOR TRANSFER OF SOLID WASTE INCLUDING AT LEAST 30% BY WEIGHT OF CELLULOSAMATERIAL TO SOLID, INERT MATERIAL THAT IS INSULAR IN WATER - Google Patents

Description

459 EO ES & 0 236 -E _. the temperature is below 100 ° C, to a temperature which is at least E50 ° C but which is below the purging temperature for the plastic materials that may be present in the original waste mass.

The moisture content of the solids is suitably regulated to a value of 27-30% by weight before the heat treatment.

In order to do this, the amount of powdery mass in the waste as well as the amount of fillers and additives which may be mixed with the mass, before it is compressed, can be analyzed, whereby, if necessary, water, aqueous solutions or other aqueous media are added. , such as aqueous slurries.

In order for solid bodies to be formed, the mass is also suitably compressed under a trough between 150 and S00.

According to a particularly suitable embodiment, the mass is compressed in the form of granular particles which consist of cylindrical bodies with a diameter between ä and 80 mm and a length between E and 30 mm. at least before the pulverized waste mass is compressed, according to a special embodiment, at least one additive is incorporated therein.

As additives, for example, at least one substance may be used which is selected from the following: monocalcium phosphate, phosphorus gray, calcium sulphate, urea, ammonium salt, an aqueous solution of ammonia, horax, sodium bicarbonate, sodium chloride, gelatin dry extract, root or leaf starch from sodium maniola . or liquid form or in the form of an aqueous solution or dispersion, when incorporated into the powdered waste mass.

A certain amount of quicklime in powder form may optionally also be incorporated into the pulp before it is compressed, the amount corresponding, for example, to a proportion between 0.3 and 10 2 of the pulverulent waste pulp. The purpose of the incorporation of unleached lime is to achieve an increase in the temperature of the waste mass to a value which is optimal for the pressing process, ie up to a temperature of, for example, of the order of 80 ° C. due to the reaction between unleached lime and water in the waste mass. The crude lime can be incorporated into the waste mass alone or in admixture with a certain amount of at least one calcium salt, such as carbonate, in, for example, a Cau / CaCU weight ratio, between 2: 1 and 1: 5.

According to a particularly suitable embodiment, during the initial heating phase the core of the solids in the waste mass is heated to a temperature between E50 and 300 ° C, after which they are kept for a certain time at this temperature, the initial heating phase being followed by an intermediate cooling phase. , during which the temperature gradually drops to a value between SO and B0'C, and a final phase, the temperature being kept between 50 and B0 ° C.

The total time for the heat treatment is suitably between 80 and QS minutes.

Likewise, the total time for the initial heating phase suitably corresponds to about 1/3 of the total time for the heat treatment.

According to a particularly suitable embodiment, the heat treatment takes place by moving the granulated particles at a constant speed from a first heating zone, in which the temperature is between E50 and 300 ° C, to a final heating zone, in which the temperature is between 80 and B00 ° C. , the particles passing through an intermediate zone, in which there is a temperature gradient corresponding to the temperature gradually changing in the direction of movement of the granulated particles between the temperature in the first heating zone and the final heating zone, the granulated particles being introduced at the beginning of the first heating zone at the same time as quicklime in powder form or a powdery mixture of quicklime and at least one calcium salt in a solid, finely divided state.

The calcium salt is suitably calcium carbonate.

Just before the granulated particles are subjected to heat treatment, a proportion of quicklime or a mixture of quicklime and at least one calcium salt is added, which suitably corresponds to 0.3-0.5% by weight of Caü and 0.3-0.5% by weight of calcium salt.

According to a particularly suitable embodiment, the heat treatment takes place by passing the granulated particles through a rotating tunnel furnace, the shaft being the furnace being the fixed ones in which the rotating device is arranged in a practically horizontal position and provided with an inner helical ramp that allows the bodies to be transported at a constant speed from one end of the oven to the other.

The materials that can be subjected to the process according to the invention can have very different origins and composition.

This may, for example, be household waste as well as waste or residual products from industry.

Given the nature of the materials, which in practice consist of mixtures of products of varying origin, it is obvious that the composition may vary somewhat. In general, however, it is particularly suitable that the average composition of the treated material is within the following limits (expressed in% by weight): cellulosic material: 50-50 2 starch-containing materials (such as leaf and root starch); S-7 2 plastic materials (resins of synthetic polymers 6-7 2 silicon-containing materials: 3-Q 2 Before the process is used, the rubbish and waste collected at the collection point are subjected to sorting and screening in the usual way, in order to recover the recyclables and / or The production of the waste mass in the form of a homogeneous powdery mixture which is substantially free of metallic material, in particular iron, can be effected by grinding and mixing, which can be carried out simultaneously or separately and combined with one or more sorting methods, which are intended to separate the metal pieces, especially the pieces of Iron-based material.

The husk can, for example, be subjected to a first coarse grinding to an average coarseness of the pieces of about SO mm, the grinding being carried out before or after a magnetic separation, which is to remove iron particles and other ferromagnetic material, which separation is followed by a second grinding carried out by a rotary hammer mill, whereby BO ES Q0 459 236 .._. 5_. the size of the particles in the mass is reduced so that it does not exceed 5-B mm.

To the waste pulp, suitably after the powdery mixture has been prepared, a supplemental filler may be added so that the total composition of the pulp changes, whereby in particular the composition and properties of the final product are affected and, for example, the desired density is achieved. The addition of the supplementary filler can either be done before the binder is incorporated into the ground waste mass or at the same time as this takes place. As component 1 of the complementary inorganic filler, for example, one or more materials can be used which are selected from the following: potassium carbonate, gypsum, burnt gypsum, flue gas from blast furnaces, magnesium oxide, barium sulphate, lithopone, dolomite, clay material, carbon powder.

The total proportion of material, of which the supplementary filler consists, is then that it constitutes ED-H0% by weight of the total amount of mixture of waste mass and filler.

The additive is suitably incorporated into the ground pulp, which may comprise supplemental fillers, in a mixing apparatus (e.g. a vertical mixing device), after which it is for a time in another mixing apparatus (e.g. a horizontal mixing device), wherein Impregnation of the waste mass takes place by means of the additive for, for example, a period of the order of 15-80 minutes, so that a homogeneous mixture, in which the additive completely impregnates the ground material, is provided by ground material and additives.

As additives, all materials in the form of powder, liquid or paste can be used, which can be incorporated intimately and homogeneously in the ground material and give such properties, especially in terms of plasticity and flowability, that it later becomes possible to bring the mixture in the form of solids. bodies which can retain their cohesion during the final intestinal chemochemical treatment.

As an additive, for example, a substance prepared by heating at least one of the solubilizers in water at a temperature exceeding 50 ° C (preferably in the proportion by weight relative to the amount of water used below) should be used: 459 256 80 85% O monocalcium phosphate: 0.2-1.5 2 phosphorus grade: 0.8-1.5 2 calcium sulphate: 2.5-7.5 2 urea: 0.5-E 2 ammonium salt: 1.0-3.0 2 aqueous solution of ammonia at 30 'Baumä: 1.0-3.0 2 borax (eg the product known under the commercial name "nëobore" J: 0.3-8.0 2 sodium bicarbonate or sodium chloride: 0.3 -1.5 2 dry extracts of gelatin (eg bengelatin): 1.8-3.0 2 root starch Eran manioc: 2,0-8,0 Z leaf starch from manioc; ¶, 0-12,0 2 sodium alginate: 8,0- 8.0 2 carboxymethylcellulose: 1.5 -%, 0 2 metgloellulose: 1.0-3.0 2 modified methylcellulose (eg the product known under the commercial name "Ihglose"): 1.5-5.0 2 plasticized polygwing acetate: 2.0-8.0 2 polygving alcohol: 2.5-8.0 2 urea formaldehyde resin: 0.5-3.0 2 phenolic resin: 1.0-8.0 2 polygwing alcohol solvents insoluble in polygving alcohol, soluble in melamine formaldehyde resin silica coumaron resin silicate of potassium or sodium etc.

As additives, a powdery product may be used in particular which consists of a mixture in which the weight ratio is between 1: 8 and 8: 1, comprising from a first powder 0.3-1.2 parts by weight of potassium sulphate 0.3-1.8 parts by weight of monopotassium phosphate 0.5-E parts by weight of borax 0.5-E parts by weight of urea 0.5-3 parts by weight of hengelatin 0.1-1 parts by weight of carboxymethylgloellulose - SO parts by weight of calcium carbonate and a second powder prepared by drying manioc moles which have been annealed to swell by heating to the boiling point in an aqueous medium comprising Eormaldehgd and ammonia (where, for example, 0.5-E parts of formaldehgd and 0.5-E parts of ammonia at & O 'Baumä were used per 10-50 parts by weight of cassava flour ). The amount of additive may, for example, be between 0.5 and 5% by weight in proportion to the weight of the homogeneous waste mass. The mixture of waste pulp (possibly containing additional fillers and additives and, where applicable, quicklime or a mixture of quicklime and at least one potassium salt) can be pressed in a manner known per se depending on the form in which it is desired to give it. In order to provide a granular material, for example in the form of small oblongs with a length of 5-30 mm and a diameter of Q-80 mm, a granulating apparatus of industrial type is suitably used, which allows granulation to take place under a pressure of 150-S00 bar.

The mixture of waste pulp and additives and / or inorganic fillers can also be pressed into shaped pieces with a size of several centimeters, which can serve as construction elements in walls or for paving or be in the form of plates or boards which can serve as revealing elements for walls. the proportion of quicklime or mixture of quicklime and calcium carbonate is suitably 0.3-0.5% by weight of Caü and 0.3-0.5% by weight of calcium carbonate in relation to the solids which are subjected to the heat treatment. The total heating time is suitably between BO and 35 minutes, the first heating phase suitably corresponding to 1/3 of the total heating time.

According to an embodiment particularly suitable for the process, the heat treatment is carried out by moving the solids to be treated at a constant speed from a first heating zone with a temperature between E50 and 300 ° C to a final heating zone with a temperature between 50 and 80 ° C. , passing through an intermediate heating zone, in which there is a temperature gradient corresponding to the temperature gradually changing in the direction of displacement For the solids between the temperature in the first heating zone and the final heating zone, the solids being subjected to the heat treatment being 459 236 ä0 introduced at the beginning of the first heating zone at the same time as quicklime or a mixture of quicklime and calcium salt, for example by sprinkling the solids with powdered lime or the powdered mixture of quicklime and calcium salt just before the bodies is introduced into the first heating zone.

To carry out the heat treatment, a tubular rotary kiln with a shaft mounted in a practically horizontal position is suitably used, the material being subjected to the heat treatment being introduced at the end of the kiln corresponding to the first heating zone and the material subjected to the heat treatment comes out of the oven near the opposite end. The end product is in the form of inert and insoluble pieces, for example non-glitter-shaped granulated material which consists almost exclusively of inorganic material and has a limestone-like structure. This product can be used in many ways, especially as a building element, for renovation or design in the building industry and engineering.

In the following, the invention is explained in more detail by means of non-limiting examples: Example 1 Municipal waste, which essentially consists of household waste, is received directly in a receiving funnel which continuously feeds a primary waste mill with a ballistic, S meter hdg chimney at a constant speed, which makes it possible to dispose of any solid material that may be present in the waste, in particular pieces of scrap metal with a mass between 50 g and 3 kg, and an explosion-proof device (armor plate). waste When the waste comes out of the waste grinder, it passes through a screening drum which means that objects with a maximum thickness of 8 om can be separated, the remainder being led to the primary receiving pocket. The waste separated in this way is led on a rolling mat which is connected to a magnetic deflection device and a magnetic block applied at the beginning of the mat, so that all particles of ferromagnetic material, which could remain in the waste which will from the primary waste grinder, can be withdrawn. The waste treated in this way then falls back to a secondary waste mill, in which it is possible to reduce the average coarseness of the particles to E-30 mm. The ground waste pulp was then added to a belt mixer, in which a binder is added, which binder is prepared by mixing 10 parts by weight of manioc flour and E, 5 parts by weight of aqueous solution of sodium hydroxide at 32 'Baumä and 8.5 parts by weight of aqueous solution of hydrochloric acid at 32' Baumä with 100 parts by weight of water, after which heating takes place at 50 ° C for 15 minutes and the mixture is finally dried so that a practically dry powdery product is formed. A homogeneous, powdery mixture is thus obtained, which mixture is introduced into a rotary granulating device, in which non-cylindrical granulated particles are formed by compressing the mixture under a pressure of S00 bar, the particles having a diameter of 5 mm and a length of 15 mm. The granulated particles thus obtained contain about 30% by weight of moisture.

Both the granular particles and a mixture of quicklime and calcium carbonate in an amount corresponding to 0.35 2 finely powdered quicklime (average grain size = S0-100 gm) and 0.35 2 technical potassium carbonate in powder form (average grain size: BO-150 gm) comprising at least E0% by weight of calcium was continuously added to the entrance of a tubular rotary kiln with a diameter of 1 m and a length of 8 m, wherein the rotational speed is regulated so that the passage time of the treated material in the kiln is of the order of 0 minutes.

The tubular furnace is heated by means of a gas burner arranged at the end through which the granulated particles and the mixture of quicklime and potassium carbonate are introduced into the furnace. The granulated particles are gradually introduced into the furnace by means of a helical screw arranged therein and exit at the end opposite to the one through which they were inserted, the granulated particles being in the furnace for a total of 0% of minutes. When the granulated particles are in the furnace, they gradually pass into a first heating zone, where they are for 15 minutes at a temperature between EBO'C and E50'C, after which they are for 15 minutes in a intermediate zone, in which the temperature drops almost inwardly from 2S0'C to B0'C, after which they are finally for 10 minutes in a final heating zone, in which they are kept between 80'E and 50'C.

Example Q 459 236 _ m _ The same procedure as in Example 1 except that at the same time as the binder an amount of high gypsum waste is incorporated into the ground waste mass, which amount is such that the proportion of gypsum is 30% by weight in relation to the total amount of waste and supplementary Egllmadal, which consists of plaster.

Claims (15)

10 15 BO 25 30 35 Q0 459 236 _ 'I _ PRTENTKRHU A process for transferring solid waste comprising at least 30% by weight of cellulosic material to East, inert material which is insoluble in water, characterized in that the metal objects which may be present in the waste are removed, after which the waste is ground and homogenized so that a homogeneous, powdery mass is formed which is pressed in the form of a plurality of solid bodies, after which the bodies in the presence of quicklime are finally subjected to a heat treatment which comprises an initial heating phase which provides a rapid heating of the core of the bodies from an initial temperature below 100 'C to a temperature which is at least E50 ° C but which is less than the pgrolg temperature of the plastic materials which may be present in the original waste mass. E. 2. A method according to claim 1, characterized in that the moisture content in the solids is regulated to a value of 27-30% by weight before the heat treatment. Method according to claim 1 or E, except that the mass is compressed under a pressure between 150 and 900 bar. ä. 4. A method according to any one of claims 1-3, characterized in that the mass is pressed in the form of cylindrical bodies with a diameter between ä and EO mm and a length between E and 30 mm. A method according to any one of claims 1-E, wherein the falling mass is compressed, means. 5. A process according to claim 5, characterized in that at least before the powdery substance is incorporated therein at least one additive characterized in that at least one substance selected from the following is used as additive: monocalcium phosphate , phosphorus gray, potassium sulphate, urea, ammonium salt, aqueous solution of ammonia, borax, sodium bicarbonate, sodium chloride, dry extract of gelatin, root or leaf starch of manioc, sodium alginate, carboxymetho-gloellulose, methglcellulose , resin insoluble, polygwing alcohol solubilizer Insoluble, potassium silicate, polygwing acetate, phenolic resin, melamine formaldehyde resin coumarone resin, urea formaldehyde resin, sodium 459 10 15 20 ES 30 35 QO 236 _. silicate, the substance being in the form of a powder, aqueous solution or dispersion, when incorporated into the pulverulent waste mass. A method according to any one of claims 1-E, characterized in that a supplementary Egl agent consisting of at least one inorganic material is incorporated in the waste mass. , B. Process according to Claim 7, characterized in that the inorganic material is chosen from the following materials: potassium carbonate, gypsum, burnt gypsum, blast gas from blast furnaces, magnesium oxide, harium sulphate, lithopone, dolomite, clay material and carbon powder. S. 9. A method according to claims 7 and 8, characterized in that the proportion of supplementary Egll means is such that the filler constitutes 20- & 0% by weight of the total amount of mixture of waste pulp and supplementary Egller. 10. A method according to any one of claims 5-8, characterized in that an amount of quicklime between 0.3 and 10 2 is incorporated into the powdery waste mass before it is compressed. 11. ll. Process according to any one of claims 1-10, characterized in that during the initial heating phase a heating of the core in the solid bodies is effected to a temperature between E50 and 300 ° C, after which the bodies are kept at this temperature for a certain time. , and that this initial heating phase is followed by an intermediate cooling phase, during which the temperature gradually drops to a value between 60 and 80 ° E, and a final phase when the temperature is kept between 50 and B0'C. 12. A method according to claim 1 or claim 11, characterized in that the total time for the heat treatment is between 20 and ES minutes. A method according to any one of claims 1, 11 or 18, characterized in that the total time for the initial heating phase corresponds to about 1/3 of the total time for the heating operation. leeward. 14. A method according to any one of claims 1-13, characterized in that the heat treatment is performed by moving the solids from a first heating zone at a constant speed with a temperature between E50 and 300 ° C at a constant speed. 236 -Ia _. to a final heating zone with a temperature between S0 and 80 ° C, passing through an intermediate zone, wherein there is a temperature gradient corresponding to the temperature gradually changing in the direction of movement of the solids between the temperature in the first heating zone and the temperature in the final heating zone, wherein the solids are introduced into the bed of the first heating zone at the same time as quicklime or a mixture of quicklime and at least one calcium salt. A process according to claim 1%, in that the potassium salt is potassium carbonate. A method according to any one of claims 1 to 15, characterized in that the proportion of quicklime or mixture of quicklime and at least one calcium salt brought into contact with the solids immediately before the heat treatment corresponds to 0. , 3-0.5% by weight of Caü and 0.3-0.5% by weight of calcium salt in relation to the weight of the solids. A method according to any one of claims 1-15, characterized in that the heat treatment is performed by passing the solids through a rotating tunnel furnace, wherein the axis of rotation is arranged in a practically horizontal position and the furnace is provided with an internal, helical ramp that makes it possible to transport the bodies at a constant speed from one end of the oven to the other. 15. A method according to any one of claims 1, E or 5-10, characterized in that the homogeneous, powdery waste mass is pressed into a brick shape or in the form of tiles. k ä n n e t e c k n a t