JPH08168694A - Method of recovering valuable object from sludge of burned trash - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a coarse fraction other than a fine fraction containing the greater part of a residual harmful substance suitable for a building material or the accumulation of a waste refuse disposable yard by roughly purifying a waste refuse incineration sludge immediately after discharged from a furnace without precooling the same and dividing the same into at least two fine and coarse fractions. SOLUTION: The dry sludge fed out of an incinerator is transported into a post-treatment apparatus to be allowed to reach a rod-shaped screen at first to mechanically separate too large particles. Next, this roughly screened substance is advanced on a 2 mm screen operated electromagnetically to separate a fine fraction to reduce dust addition capacity for a succeeding treatment process. This fraction contains up to 90% of a harmful substance contained in the coarse sludge. Next, a >2 mm coarse fraction is sent to a perforated screen with a perforation size of 25-35 mm and the overflow component from the screen is passed through a reading plane to separate non-combustion matter and obstruction matter. Subsequently, the rough fraction is ground by a hammer mill to obtain valuables from which dust particles are removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is directed to at least 2 sludges that have been dried and rough cleaned by leaving the crude sludge directly after exiting the furnace and without prior cooling in a water bath to Grobreinigung. The present invention relates to a method for recovering valuable substances from refuse incineration sludge, which is divided into one fraction and all particles smaller than 2 mm are distributed to the first fraction and the remaining particles are distributed to the second fraction.

[0002]

2. Description of the Related Art When incinerating refuse from residential areas, about 250 kg of sludge is generated as a residual substance per ton of dust.
The resulting sludge has a content of harmful substances immediately after the furnace,
This harmful substance prevents further use of the sludge, for example as a building material. Accumulation of sludge at the landfill would threaten the environment if no special measures were taken, such as the collection of seepage water.

Usually, this sludge is cooled in a sludge dewatering unit immediately after leaving the furnace. In this case, the heavy metal content in the sludge is reduced. However, this is not sufficient and leaves a significant content of toxic substances in the sludge.

By the way, European Patent No. 0372039 presents for the first time one processing method for post-treating sludge from a refuse incinerator, in which case the sludge is immediately after the furnace in a water bath. Rough cleaning without cooling in advance (removal of coarse materials and magnetic members that did not burn)
Sent to. After this, the sludge that was rough cleaned was
Divided into at least two fractions, and into one fraction,
All particles that are less than 2 mm are distributed.

The above-mentioned known method is based on the recognition that the fine fraction contains most of the harmful substances contained in the sludge when it originally exits the sludge. This fine fraction is quantitatively small compared to the coarse fraction and must be sent to the sorting process. This coarse fraction, on the other hand, is suitable for direct use as a building material or for deposits at landfills. Suggestions for recovering valuables other than sludge valuables are described in EP 0337203.
It cannot be read from the 9B1 specification.

[0006]

The present invention, as characterized in the claims, optimally adapts the dried, discharged sludge to the starting material and brings the recovery of valuables to the front. The task is to describe a method of the kind mentioned at the outset.

[0007]

The advantages of the present invention are
With inert substances, for example sludge in the quality of building materials, ferrous, non-ferrous metals, among others, aluminum and copper,
It is able to separate heavy metals loaded finer substances. Then, the said heavy metal-loaded finer substances, which make up only about 30% of the total weight, can be sent to the sorting process.

[0008]

EFFECTS OF THE INVENTION By carrying out the sludge from the incinerator by drying, the valuable material is sufficiently free from the adhesion of the inorganic substance. This also avoids the progress of chemical reactions between alkaline sludge, which typically contains 10-15% CaO, and water, for example the oxidation of metallic aluminum.

The invention and the advantages achievable with it are explained in more detail below on the basis of examples.

[0010]

[Example] The sludge dried and carried out from the combustor is conveyed to a sludge post-treatment device schematically shown in the figure, and in the sludge post-treatment device, first, a rod-shaped sieve (Stangensieb)
To reach inside and oversize the granular material (300 mm
Material that exceeds the above) is mechanically separated. This makes it possible to avoid subsequent sieve loading and damage.

The coarsely screened material is then advanced over an electromagnetically operated 2 mm screen. In this way, the fines are separated, and thus the dust loading capacity for subsequent processing steps is reduced. According to the teaching of EP 0 372 039 B1 cited at the outset, this fine content is equal to 90% of the harmful substances contained in the crude sludge.
Contains up to%. This fine content is sent to the sorting process.

For the next step, a coarse content of> 2 mm
Feed through a sieve, typically having a pore size of 32 mm, preferably a vibrating sieve. Read the overflow from the screen (Leseeben
e) and the non-combustible material (wood,
Paper) and obstructions such as electric motors, small transformers,
Separate the electromagnet and coil. In this case, the removal of obstructions containing other metals, especially copper, together with iron is such that objects of this kind are usually distributed during the subsequent magnetic separation to the iron fraction, which It is especially important as it reduces the quality of the iron fraction.

The material is subsequently ground in a hammer mill. Further separation of iron using ultra high frequency magnet (Ueberband magneten). Iron is of high quality because the dust particles adhering to it are sufficiently removed by the dry discharge of sludge and the processing in a hammer mill. 32 of this ground and no longer iron-free material
Return on mm mm sieve.

By sieving this 32 mm hole sieve, in a mill, for example a ball mill or a vibration crusher (Oszillatorbr).
Echer) selectively divided into two fractions. In this case, the ash-like heavy metal-loaded material is ground, but the inert materials, such as glass, ceramics, clays, stones, etc., leave this process essentially unground.

The material stream is passed through a magnetic separator towards the mill, in which the iron is again separated with high efficiency.

Next, both particle fractions are separated behind a magnetic separator on a mesh screen (Spannwellensieb). The loaded fines with a particle size of less than 2 mm are preferably worked up together with the fines from the first-pore sieve, for example by solidification or melting. Nonferrous metals (Al, Cu, etc.) are separated from the coarse fraction as valuables, for example, by using a vortex flow separator. The quality of the separated metal is very good due to the dry sludge discharge of the crude sludge.
For example, there remains an inert material that can be reused for road construction.

[Brief description of drawings]

FIG. 1 is a system diagram schematically showing an apparatus composed of individual structural units for recovery of valuables from waste sludge incineration sludge that has been dried and carried out.

Claims (4)

[Claims] 1. The crude sludge is fed directly after leaving the furnace directly into a rough cleaning without cooling in a water bath and the dried and rough cleaned sludge is divided into at least two fractions and 2 mm. In the method for recovering valuables from refuse incineration sludge, which allocates all particles that are less than 1 to the first fraction and allocates the remaining particles to the second fraction, the second fraction is divided into the second fraction. Characterized in that it is divided into at least two fractions on the side in a sieving step and all particles which are between 25 and 35 mm are distributed to the third fraction and the remaining particles are distributed to the fourth fraction. , A method of recovering valuable materials from refuse incineration sludge. 2. A new sieving is carried out after the separation of iron carried out in the process of processing the third fraction, and <2
2. The process according to claim 1, wherein the fine fraction of mm is separated and post-processed with the particles of the first fraction, preferably solidified or melted. 3. The method of claim 2, wherein a non-ferrous metal overflow is discharged in the vortex flow separator. 4. A fourth fraction is passed through a reading plane, at which reading the unburned material and other obstructions are separated, after which the material is mechanically comminuted and any further iron present. 2. The method according to claim 1, wherein the screening and thus returning the substances which are free of obstructions and iron to the sieving step.