NO159904B - PROCEDURE FOR THE CLEANING OF CORNED MATERIALS, AS ROLLING OR OIL-MINERALS, FOR ANY FAT MATERIALS, SPECIAL OIL. - Google Patents

Description

The invention relates to a method for cleaning med

fatty substances, especially oil, soiled roller coating ("Walz-zunder"), especially from rolling mills, where the roller coating is washed in a washing liquid, then separated and dried and where further it for oil resp. Degreased washing liquid is returned to the process.

From DE-PS 25 32 689 a related method is known, in which the roller coating is first mixed with 10-20% by weight solvent and the fat is finely distributed in the mixture.

The mixture is continuously added to a solvent bath

and distributed therein, and the roller coating is conveyed under further mixing with oil-free solvent flowing countercurrently slowly from the solvent bath. During further transport, the solvent is brought to drip from the now grease-free roller coating or is expelled by heating and the roller coating is dried. The fatty solvent is regenerated by distillation. After its condensa-

tion is added to the fat or the oil-free solvent in fat in a circuit to the fat-containing, preferably to 40-45°C heated roller coating.

The device for carrying out the known method

consists in that a driven, horizontally lying, double-shaft mixer equipped with a solvent addition device is connected to a chopping device. Its outlet consists of an outlet funnel which, with its opening, reaches into a deposition stream equipped with a solvent bath, in which one end of a transport auger transporting at an upward angle is arranged. A solvent addition device is arranged above the transport auger and at the outlet end of the transport auger there is a filling

the end of the rotary weight conveyors at the upper exit of which it is connected to a sedimentation basin with transport auger, a dewatering sieve and a drip silo. The facility is closed by means of a housing gas-tight from the outer atmosphere and has

a distillation and condensation device for solvent recovery. Fluorinated hydrocarbons, especially fluorotrichloromethane, or similar organic substances are used as solvents, which are mostly toxic.

This method of working is very cumbersome. In particular, the high energy consumption is seen as unfortunate and caused by expelling the solvent, its distillation preparation as well as heating the roller coating, etc. Furthermore, the major work for the leak-free wiring and the gas-tight shielding of the overall plant above the external atmosphere which is necessary to avoid loss of solvent and not to pollute the atmosphere.

The invention is based on the task of cleaning roller coatings contaminated with fatty substances, especially oil, by a simple washing procedure in an aqueous washing bath, as there is no disturbing consumption of heat energy.

The invention thus relates to a method for cleaning granular materials such as roller coatings or oily minerals from entrained fatty substances, especially oil, where the materials are washed with a washing liquid containing a solvent, separated from this and then dried, and where the washing liquid freed from fatty substances is returned to the process, as the method is characterized by the materials, possibly broken to grain sizes below 1 mm for surface polishing, being subjected to mechanical stress, where the average grain size is only slightly reduced, and then washed in a flotation (2,3) that the materials are separated from the ongoing flotation and then dried and that the overflow liquid removed by the overflow (18, 20) of the flotation (2, 3), then freed of the fatty substances, and/or the washing bath formed after flotation by separating the granular materials is returned in the process.

It has surprisingly been shown that a solid-state mechanical stress is excellently suited to condition the roll coating for a subsequent washing treatment.

Appropriately, the washing liquid consists of water during addition

of known laundry detergents, there are surface-active, anionic resp. cationic or also non-ionic compounds such as aryl alkyl sulphonates, fatty acid condensation products, alkyl polyglycol ethers and the like. The solid state mechanical stress is preferably carried out by painting the roller coating.

That a washing of the roller coating in high-quality fat-dissolving organic solvents during similar work leads to the liberation of the coating from oil and fat components is in principle self-evident and known. The starting point for the invention is that, however, washing processes known from other areas of application with aqueous washing solutions, at least with a suitable material and apparatus work for roller coating, do not lead to satisfactory results.

For the pre-treatment of the roller coating, claims 3 and 4 usually satisfy a grinding time of 2-5 minutes, the average grain size of the roller coating particles according to claim 6

and 7 is only reduced slightly, for example around . 4-6%.

The solid mechanical stress, especially in the form of a paint, probably reduces the adhesion forces between the roller coating and adhering oil or fat and thereby make it possible to increase the cleaning effect of the washing water.

It therefore pays to paint the roller coating

in wash water, preferably in a recirculated wash bath, and thus carry out a pre-wash of the coating. Such painting treatment in humidity also favors interface reactions

in the capillary area and provides an activation of the roller coating particles for the subsequent washing process with gentle mechanical stress on the roller coating body.

After the aforementioned pretreatment, the roller coating receives a main wash, during which it is subjected to a flotation (flotation treatment). Such flotations in an aqueous flotation bath are known and widely used in coal and ore preparation. It is usually sufficient to submit the roller coating

to be cleaned, suitably pre-washed in a mill, for a two-stage flotation...

It has been shown that the above-mentioned separation method cannot only be used to separate oil or fat chartered roller coating, but surprisingly is also suitable for separating petroleum from oil-bearing minerals, especially sand and rock. For this, it is only necessary that the roughly cut built-up stones or sand is appropriately crushed before being treated analogously to a soiled roller coating.

The plant for carrying out the method according to the invention only needs to consist of a few, otherwise known components, in order to achieve a good cleaning of the roller coating with relatively little work. The facility has

a painting unit, a rotary machine connected to the painting unit,

a solids separator connected downstream to the flotation underflow and a final dewatering machine connected downstream.

In order to enable continuous cleaning, a filling station is connected in front of the painting unit, which doses the timed input quantity for the roller coating to be cleaned. The grinding plant can consist of a drum mill with loose grinding bodies, especially grinding balls. Its bottom area is suitable and arranged as a washing container for pre-washing the roller coating, as it conveniently opens into the paintwork into a return line for the washing bath. The main washing of the roller coating resp.

the pulp contained therein takes place in an ordinary flotation machine with several flotation cells which have a common overflow chute. In this, the washed out oil or grease together with floated roller coating particles and entrained wash bath. To further work up this extracted mixture, in particular to separate the aforementioned components from each other

and especially to separate oil and grease, the overflow chute at the flotation machine - for main washing - can be connected to a further flotation device, the outlet overflow of which opens into a three-stage separator. This further flotation device can consist of two flotation cells connected in series, so that the overflow chute of the first cell opens into the bottom of the second cell

run and the latter's overflow chute are connected to the wood separator. Appropriately, the underflow of the last cell is returned to the inlet of the first cell, so that circulation can take place several times.

In the aforementioned additional flotation device, a good separation of oil and grease from the oil-solids-water mixture floated out in the main washing, so that the resulting washing bath with its solids part can preferably be returned to the washing process for the roller coating pulp to be cleaned. For the addition of necessary flotation reagents and detergents (detergent) as well as the introduction of a recirculated wash bath, it pays to connect a conditioning container between the mill and the flotation machine for the main wash.

The flotation machine for main washing of the roller coating can be designed as two-stage, in that an additional flotation cell is connected to the first regularly multi-cell flotation stage, whose overflow chute has a return line for the washing bath leading to the conditioning container. A return line for the washing bath from the additional flotation device for preparing the oil-solids-water mixture also conveniently opens into the conditioning container.

1 Also for the extraction of petroleum from oil-bearing rock, the above-mentioned plant is well suited when it is ensured that a corresponding crushing of the broken mineral material occurs in the grinding plant, so that the rock digestion takes place into the oil-containing capillaries. Appropriate

one therefore wants to connect a ground, cone or roller switch before the grinding machine for crushing.

In what follows, the invention will be explained in more detail

by means of the drawing showing an exemplary embodiment.

The installation shown in the drawing for carrying out the method according to the invention is distinguished in its basic structure by a grinding unit 1, a flotation machine 2,3, a solids separator 4 and a dewatering machine 5.

For example, from a rolling mill or a continuous casting plant, rolling coatings that are usually present as damp with oil or fat soiled sludge, kept ready in a filling station 6

and supplies, by means of a screw outlet conveyor 7, via line 8, quantity dosed to the grinding unit 1, which is designed as a drum mill with grinding balls. The drum and the paintwork 1 are rotatable by means of a casing drive 9 shown only schematically and are arranged as a washing container for pre-washing the washing coating. The output of the painting plant 1 is via line 10, preferably an intermediate container 11 and line 12 connected to a conditioning container 13, in which is arranged piping 14. This is the main part 2 of the flotation machine for main washing of the roller coating and which consists of several flotation cells. 16 with piping 17, as all cells have a common overflow end 18. Air is introduced into the cells 16 in a known manner, which is not shown in the drawing, so that the piping 17 constantly produces a finely beaded airflow in the flotation bath. To the main part 2 of the flotation machine, an additional flotation cell 3 with piping and finely dispersed air flow is connected via line 19 as the second stage of the flotation machine. Its overflow chute 20 opens over a return line 21 in the conditioning container 13. From the underflow of the flotation cell 3, a line 22 leads to the solids separator 4, which is designed as a magnetic separator. The separated 'thickened roller coating (solid material) is supplied via line 23

for further dewatering drying to the dewatering machine 5

and comes from there on the conveyor belt 24. The lines 25 and 26 are joined at 27, they are liquid drains for the washing bath which only also contain very fine solid particles in smaller quantities. The downstream clarification device 28 for the washing bath, for example a lamellar clarifier, has an outlet auger 29, so that thickened sludge is fed via line 30, for example into a settling basin not shown. Spillway 31 is above the line

32, possibly an inlet container 33 and return line 34 connected to the painting unit 1.

From the common overflow chute 18 of the main part of the flotation machine

2 for roller coating washing leads line 35 and inlet container

36 to a further two-stage flotation apparatus for preparation of the floated oil-enriched mixture, where a first flotation cell 37 is connected with another flotation cell 38, in such a way that the overflow chute 39 over line 40 opens into another cell 38. The underflow 43 of another cell 38 is returned via return line 44 into inlet container 36 and thus the inlet of first cell 37 and thus forms a circuit. The indicated pipework for producing a finely beaded air flow is denoted by 41,42. The overflow channel 45 of another cell 38

is connected via wire 46 to the wood separator 47 which has . each time an outlet for essentially oil (outlet 48), solids (outlet 49) and washing liquid (outlet 50). Outlet line 50

is fed into inlet container 33, the washing bath is returned via line 34 to the painting unit 1.

The moist roller coating coming from the filling station 6 is subjected to solid-state mechanical stress in the drum mill (grinding unit 1) under the influence of grinding balls and grinding walls, whereby the adhesion forces between oil and grease and roller coating particles are reduced. A painting time of 2-5 minutes is usually sufficient to achieve conditioning of the roller coating for the subsequent washing process. This results in only a small reduction in the average grain size of the roll coating particles, for example around 4-6%,

the roller coating particles, which were strongly cleft at their surface, were thereby essentially only smoothed. In the drum mill 1, the roller coating is pre-washed in the above line 34 back

led to a cleaned washing bath, so that a preconditioned pulp comes via line 10,12 into the conditioning container 13.

In the container 13, the pulp is set for the subsequent flotation. It takes place in a manner known from other flotation processes, for example from ore and coal preparation, as the pulp is made highly alkaline by the addition via line 52, for example of caustic soda, and further flotation agents (foam formers) are added. Furthermore, the required amount of washing detergent is added here in the container 13.

In the main part 2 of the flotation machine for the roller coating washing, the oil and fat components float up with their significant amount to the overflow chute 18, so that from line 19 at the flotation underflow flows a pulp of washing bath and heavily de-oiled roller coating into the additional flotation cell 3 of the flotation machine. At the overflow chute 20 of cell 3, a dispersion of washing bath, floated roller coating particles and residual oil is produced which is returned via line 21 into the conditioning container 13 before flotation, so that the given circuit results in a repeated washing of this part of the goods with possibly several separations. The de-oiled and degreased pulp in line 22 in the underflow of cell 3 enters the magnetic separator (solids separator 4), where solids are separated, then dried dewatering and fed to a conveyor belt. The washing bath formed during the solids separation and dewatering is returned to the process, as the clarified bath is supplied to the painting unit 1.

The roller coating comes on conveyor belt 24 as cuttable or malleable material whose moisture content can be adjusted for later use, for example pelletisation.

The cleaned roller coating is heavily freed of oil and grease components.

In the overflow chute 18 of the main stage 2 of the flotation machine for the roller coating washing, a foamy dispersion of predominantly oil with washing liquid and suspended fine solid particles collects. The pulp floats in the cells 37,38

in series and in a circuit partly several times, so that in the outgoing overflow chute 45 a liquid oil product with small admixtures of washing bath and solid material is separated from each other in the wood material separator 47. At sub-

in the course of the flotation cell 37, a washing bath is produced that is heavily oil-free, which, however, predominantly contains the solid parts from the foamed dispersion in the overflow chute 18 of the main part 2 of the flotation machine. Via line 51, this washing bath with its solids (roll coating) can be fed into conditioning7

in

container 13.

In the tests carried out, the roller coating which was soiled with oil and grease and which had to be cleaned usually had normal oil contents of 3 to 5% by weight. After

cleaning treatment, the oil/fat content was below 0.3

weight-%. Numerous further processes are open to the cleaned roller coating. For example, it can be on sinter-

strip is mixed for fine ore, as there is no danger of the so-called oil fire as it is to a large extent caused by contaminated roller coating.

For the extraction of petroleum, lumps became oily

stone pre-broken to a grain band below 50 mm and then post-broken to a grain band below 5 mm, both taking place in ordinary breakers which are not shown in the drawing. The mineral material was then introduced into the grinding plant 1, where it was ground to a grain of less than 1.0 mm and further processed in the subsequent plant parts according to the drawing. Ground oils to be extracted flow with little solids and washing bath through line 46 and are withdrawn at 48 with the wood separator 47.

Claims (7)

1. Process for cleaning granular materials such as roller coatings or oily minerals from entrained fatty substances, especially oil, where the materials are washed with washing liquid containing a solvent, separated from this and then dried, and where the washing liquid freed from greasy substances is returned to the process, characterized by the possibly for grain sizes below 1 mm broken materials for surface polishing are subjected to a mechanical stress, where the average grain size is only slightly reduced, and then washed in a flotation (2,3) that the materials are separated from the ongoing flotation and then dried and that at the overflow (18, 20) of the flotation (2, 3) removed, then freed of the fatty substances, overflow liquid, and/or the washing bath formed after flotation by separating the granular materials is returned to the process. 2. Method according to claim 1, characterized in that the materials are washed with a washing liquid of water with the addition of washing detergents. 3. Method according to claim 1 or 2, characterized in that the materials are subjected to mechanical stress during painting. 4. Method according to claim 3, characterized in that the materials are ground for 2 to 5 minutes. 5. Method according to claim 3 or 4, characterized in that the granular materials are ground in washing water, in particular a returned washing bath. 6. Method according to claim 1, characterized in that the average grain size of the granular materials is reduced to around 4 to 6#. 7 . Method according to one of claims 1-6, characterized in that the flotation of the pulp containing the granular materials is carried out in two stages.