Method for continuous extraction of inorganic material from the pulp paint

 

The method used for extraction of inorganic material from the pulp ink, which is obtained as a waste material when removing the secondary fiber from recycled paper. The method includes the following operations: controlling the proportions of organic material in the form of fibrous material in the slurry paint on the level 15-40% in terms of solid content; the regulation of water content in the pulp of the paint so that the solid content becomes equal to 10-35%; increasing the pressure of the pumped slurry paint until at least 22 MPa; the temperature increase to supercritical; adding to the slurry paint containing oxygen environment; recovery released during the oxidation of organic material energy; division of flow of the material of which was allocated to energy and which contains the specified inorganic material, gases and water, moreover, the specified separation of material involves the extraction of valuable inorganic material. The method allows to extract from the pulp of paint inorganic material of high quality. 21 C.p. f-crystals, 1 Il.

The present invention relates to the creation of a method of continuous extraction of inorganic material and (recovery) secondary fiber from recycled paper.

This slurry paint has a solids content, which is typically less than 8% of the previously conducting dehydration, and has a content of organic material, which is typically more than 35%, the rest is the content of inorganic material, calculated on the solids content.

The term "waste" refers to used paper or cardboard, of which, after use, remove the secondary fiber, which then, after crushing, is used again for the production of paper or cardboard, and certain other industrial applications. Thus, the term "secondary fiber" refers to a fibrous material that was previously used in a paper or cardboard products.

The paper used for the manufacture of various types of printed products such as Newspapers, magazines, lightweight coated paper and bond paper, which contains a lot of additives. Finished printed paper products also contains printing ink. Among the additives should first specify the fillers, pigments and dyes, but there are other supplements. The number and relative proportions of different additives vary depending on the type pedaste fillers use clay, calcium carbonate, titanium dioxide and/or talc, however, can be used and other fillers. The pigment include in the coating layer of coated paper or paperboard. As pigments are mainly used clay and calcium carbonate, separately or together, but can be used as titanium dioxide and talc.

When extract (restore) a secondary fiber from waste paper waste paper is subjected to the cleaning process for bleaching fibers and remove dirt. Various received the waste is then brought together to obtain a slurry paint having a relatively high water content. Up to the present time no practical commercial method for the recovery of valuable materials from the specified slurry paint or even proposals in this area; instead, the slurry paint is used as waste, which after dehydration can be used in the manufacture of cement or brick or can be directed to combustion using known techniques. Generated by combustion ash sent to landfill. Note that some companies and countries are sent to landfill slurry paint without burning, which leads to environmental pollution.

In the article "Supercritical water oxidatges 393-403 described method of processing pulp, which can be used as an alternative to conventional waste incineration of pulp from the pulp mills. This method of supercritical water oxidation based on conducting oxidation without carbonization of the organic fraction of the pulp, in the presence of water in the supercritical state. This means that the oxidation of organic material takes place at a temperature and pressure above the supercritical point on the phase diagram of water, that is, at 374With/And 22 MPa. Oxidation of organic material at relatively low temperatures becomes possible due to the high pressure and the presence of water as a reaction medium. In its supercritical point 374C/22 MPa and in the supercritical region around this point, the water behaves as a supercritical fluid, and in this state, the supercritical water acts as an effective solvent for the organic material and gases. This article discusses only the pulp obtained by a conventional manufacturing pulp, and says nothing concerning the specific pulp paint obtained as waste when removing the secondary fiber from recycled paper, and says nothing about use is on Deinkingschlammen" by U. Hamm and L. Gottsching, Wochenblatt fur Papierfabrikation 1, 1998, pages 15-23 described the results of experiments on the deoxidation (desoxidation) pulp paint using the above mentioned method, supercritical water oxidation. From the article it becomes clear that even with a very high degree of oxidation of organic material in the pulp paint get an inorganic material with such a low degree of whiteness (less than 60% on the standard International standard organization - ISO) that it cannot be used as filler.

From European patent application EPO No. 0742310 know how to extract the inorganic material from the pulp paint waste paper products, including contact fibers of the pulp with an aqueous medium containing oxygen, at high temperature, resulting in the oxidation of organic material, and the separation of the stream containing inorganic material.

However, this method does not allow for the extraction of pulp paint inorganic material of such quality that this material is suitable for reuse in the paper production process. This result is the main task of the present invention.

The method in accordance with h the regulation of the proportion of organic material in the form of fibrous material in the slurry paint on the level 15-40%, in terms of the solids content of,

(b) regulation of water content in the pulp of the paint so that the solid content becomes ravnim 10-35%, and regulation in the operation (a) and operation (b) is conducted with respect to each other so that the slurry paint suitable for pumping pump,

(c) increasing the pressure of the pumped slurry paint at least up to 22 MPa,

(d) increasing the temperature of the pumped slurry paint to supercritical or almost supercritical temperature,

(e) adding to the slurry paint containing oxygen environment in a quantity sufficient to oxidize all organic material that occurs at supercritical temperature and pressure in the reactor,

(f) recovery released during the oxidation of organic material energy in a suitable form, and

(g) separation of the flow of the material of which was allocated to energy and which contains the specified inorganic material, gases and water, and the specified separation of material involves the extraction of valuable inorganic material.

Operations (a) and (b) adapt to each other so that after the operation (b) pulp paint has a content of chemically consumed oxygen in ttp://img.russianpatents.com/chr/176.gif">C, and the temperature in the reactor after operation (e) increase over 650C. Preferably, the temperature in the reactor was 500With up to 600C.

Gaseous reaction products, it is advisable to separate from the stream of material in the operation (g) and release to the atmosphere or to accumulate, and from the accumulated gases to remove carbon dioxide.

The slurry paint it is advisable to expose the previously washing operation (C), pulp after washing must have a salt content of at most 1000 ppm.

The time of oxidation in the reactor is about 10 minutes or less, mostly about 5 minutes or less and most preferably about 1 minute.

The fibrous material is removed from the pulp paint in order to get its content at the level indicated in the operation (a), by flotation, sedimentation, vortex cleaning, sieving, centrifugation, or a combination of two or more of these technologies that can be integrated in the process of removing ink from paper, from a remote fibrous material extracted recycled fiber.

The fibrous material may be removed from the pulp and using aerobic or anaerocellum in ethanol using enzymatic or other type of hydrolysis, followed by fermentation, as well as when using the combination of two or more of these technologies.

The water content during the operation (b) is adjusted by means of sedimentation, vortex purification, centrifugation, pressing in a suitable press, as well as when using the combination of two or more of these technologies.

Received in the operation (g) inorganic material has a degree of whiteness, which is at least 68% ISO, and it is subjected to final processing in order to increase the degree of whiteness of 2 or more percentage.

Final processing involves cleaning to remove reducing the degree of whiteness of the metal oxides and/or tooth whitening using bleaching agents.

Learned valuable inorganic material contains a pigment, the particles of which are smaller than the particles of the filler, resulting inorganic material is separated into a fraction of filler and pigment fraction.

Energy in operation (f) can recover in the form of steam and/or hot water.

The incoming pulp paint has a solids content, which is typically less than 8% previously dehydration, and has retained the ski material, in terms of solids content.

The invention will be described hereinafter with reference to the drawing, which shows a block diagram of the heat recovery installation for the extraction of inorganic material from the pulp of paint in accordance with the present invention.

Pulp ink from the cleaning process of the paper loaded in the storage tank 1 and continuously stirred to prevent sedimentation. If the slurry paint was not handled in a special equipment for dehydration, it usually has a solids content of below 8%, and typically about 5% or below, and the rest water. Pulp ink typically has a content of organic material over 35%, calculated on the solids content, and is usually in the range of 45-50%, so that the content of inorganic material lying respectively below 65% and 55-50%.

Organic material includes a fibrous material, printing ink, other dyes, various types of organic additives and a binder, and a fibrous material forms the largest proportion. The fibrous material comprises fibers and fibers (so-called "little things"). The inorganic material primarily contains a filler, but it may include other materialno serves for the installation of pretreatment 2, where carry out appropriate pre-processing in order to reduce the proportion of the fibrous material in the solids contents up to specified level. There are many different methods that can be used for pre-treatment part of the fibrous material, which allows to reduce the content of fibrous material, such as flotation, sedimentation, vortex cleaning, screening, centrifugation, biodegradation (aerobic or anaerobic), and to convert part of the fibrous material into ethanol using enzymatic or other type of hydrolysis followed by fermentation, using a combination of two or more of the following technologies, which can be held in one or more transactions. Pre-treatment of the pulp paint to reduce the proportion of fibrous material to the specified level can be integrated in the process of removing the paint. In this case, does not require a separate installation for pre-treatment. The decrease in the content of the fibrous material to levels in the range from 15 to 40% is important to obtain an acceptable saving production costs. The decrease in the content body is water ski oxidation, since in this case can be used slurry paints with a higher solids content. This, in turn, leads to a lower content of chemically consumed oxygen demand (COD), and for the better pumpability of the slurry paint. Moreover, the cost of gaseous oxygen is reduced as the ratio of organic and inorganic materials falls.

Processed in this way the pulp paint then sent for installation 3 to increase the concentration of solids to values in the range of 15-35%. This increase in concentration may be achieved through appropriate processing, which allows to directly obtain the specified range of concentration or complete a significantly higher concentration, after which the slurry paint diluted to enter the range of 15-35%. There are many different ways to improve the content of solid substances, including sedimentation, vortex purification, centrifugation, pressing in the appropriate media, and combinations of two or more of these technologies. The thickening of the pulp ink is necessary to reduce the amount of water present during the oxidation, kotoroya paint can be subjected to washing, especially if the salt content is too high. Metal ions that are removed during this washing, subsequent oxidation can form metal oxides that can be painted extracted inorganic material, thereby reducing its degree of whiteness. To avoid precipitation of salts (so-called inlay), the salt content in the process must be maintained at lowest possible level, mostly below 1000 RS (parts per million). Pulp ink after increasing the solids content must still be pumped to be able to continue its continuous processing. Thus, the adjustment of the two initial operations should be carried out together with respect to their influence on each other, so that the slurry paint was from the unit 3 in pumpable form and had the COD content of 40-200 g/l, and mainly 60-150 g/l To increase the pumpability of the slurry paint can be used in the methods of dispersion.

Pumpable slurry paint is sent to the storage tank 4, which is provided with a device for the homogenization of the pulp ink, so as to maintain in the storage tank 4 homogeneous concentration, and the Windows due to the action of the pump. Pulp ink pumped from the storage tank 4 by means of high-pressure pump 5, which creates in the pulp colors working pressure of at least 22 MPa.

Pulp ink is then sent to the heating device, in which it is heated to the required temperature, which is preferably at most 425C. heating Device comprises a heat exchanger, which operates in continuous mode, after which a heater 7, which can operate, for example, natural gas and which is connected, if the heat exchanger has insufficient performance, for example when you start recovery installation.

Pulp ink which contains water under supercritical or near supercritical state, is sent to the reactor 8, which represents, for example, a vertical reactor, a slurry paint arrives in the upper part of the reactor. Alternatively, the reactor can be in the form of an elongated tube which can be bent in the form of a flat serpentine loops or circular spiral. (Needless to say that in a process plant for carrying out supercritical water oxidation can be used reactor and the other four who frequent reactor 8, to ensure good mixing with the slurry paint. The oxygen oxidizes the organic material in the pulp paint, with proceeds exothermic reaction that creates the desired temperature rise in the reactor. This reaction is controlled so that the reactor temperature was maintained more than 500C. the Temperature is mostly supported in the range of 500-650With, and even better in the range 550-600C. the Amount of oxygen is adjusted so that the COD content was 40-200 g/l under the conditions specified temperature and pressure and with appropriate adjustment of supplied oxygen to achieve complete oxidation of all organic material in the pulp paint. The operation is carried out at a controlled temperature in accordance with the previously specified, but mainly at temperatures below 650With not to destroy the structure of the inorganic material. During continuous operation of the reactor to release the material flow, which contains solid and dissolved inorganic material, gases and water. This flow of material is passed through the heat exchanger 6, in order predator 10 (or some other energy recuperation system), which can be done to recover the remaining energy. Thereafter, the flow of material is passed through terminal cooler and device for reducing the pressure.

The cooled material flow with reduced pressure is directed to the separation plant which contains the separator 12 for separating gas from water inorganic material. The gas phase are produced through the pipe 13 into the atmosphere or accumulate appropriately for later use that form it, such as carbon dioxide, while water inorganic material in suspension away through the pipe 14. Optionally, the suspension may be condensed accordingly, for example, in a settling tank or screening device (not shown). In addition, before or after the condensation can be carried out washing to remove any residual soluble compounds. Separated water is sent to relevant collections or return to one of the operations of this process.

Then determine the properties of the extracted specified inorganic material. If you find that the degree of whiteness is about 68% ISO or above, the inorganic material can be used it established for such use. These requirements are that the material must improve optical and technical properties of the produced paper and should not have a negative impact compared with conventional commercially available products, and this material is intended to improve the efficiency of paper production process in accordance with aspects of saving resources and energy, and environmental protection.

To improve the quality, and the first degree of whiteness, the extracted inorganic material is subjected to appropriate processing in the plant for final processing 15. This can be accomplished, for example, by treatment in a magnetic separator, high gradient, which removes formed during oxidation in the reactor metal oxides, which reduce the degree of whiteness. Before cleaning can be added dispersant, allowing you to achieve the best results. The degree of whiteness can also be improved by using appropriate bleach, such as dithionite. Can also be used a combination of these treatment methods to achieve an even higher degree of whiteness. This final treatment such final or without processing, can be used, for example, as a filler in the manufacture of newsprint different brands. After carrying out the above-described final processing of this material may be used as filler in the manufacture of paper with a higher degree of whiteness, such as magazine paper, lightweight coated paper and fine paper.

Optionally, you can apply oxygen-containing environment at two or more points spaced along the reactor, and given the total number of oxygen-containing environment may be evenly distributed between these points, or may be different.

The pigment has a smaller average particle size than the filler. If the largest proportion of waste paper formed of coated paper or cardboard, it may be advantageous, using appropriate equipment, to make the separation of inorganic material on the first fraction having particles of a large size and a second fraction having particles of a smaller size, which are the pigment, and the first fraction forms a filler, and the second pigment, which can be used in the paste coating paper.

The tests showed that extracted in accordance with NASA paper production. The tests also showed that when using extracted in accordance with the present invention material as filler printed paper get satisfactory results in terms of physical, optical and printing properties.

The following describes experiments conducted in accordance with the present invention.

Pulp ink, obtained from a typical installation for the removal of ink from waste paper at a paper mill was processing the experimental flotation machine, in order to reduce the proportion of the fibrous material in the slurry paint. When carrying out the flotation was also some leaching of salts from the slurry paint. Due to flotation treatment was increased proportion of filler, calculated on the solids content of approximately 68% (32% organics) from the original 55%. It should be borne in mind that the flotation process in the course of this experiment was not fully optimized. When optimized flotation process can be achieved content of the filler, more than 80%, calculated on the solids content. Such content of the filler was obtained on other uses waste paper mill, on a smaller scale. After flavors for dehydration.

The obtained dehydrated slurry paint was then processed at the facility for supercritical water oxidation, having a bandwidth of 250 liters per hour. Oxidation occurred at a temperature in the range from 550With up to 580C, at a pressure of 25 MPa and residence time in the reactor for about 1 minute. The filler in the flow of material out of a facility for supercritical water oxidation, has a degree of whiteness of 72-73% ISO. Obtained in this experiment, the filler was then used in the full-scale experiment carried out on a machine for the production of newsprint, when the filler was injected into the pulp to increase the content of the filler. The results of this experiment show that the secondary filler has properties that are no worse than fresh filler.

In another experiment on the same setup for supercritical water oxidation was used pulp paint with another paper mill, which produces from waste paper carbon paper. After treatment with the process of supercritical water oxidation was obtained filler having a degree Belize the experiments using a slurry paint, to which was previously added an extra filler in the form of clay and chalk, so that was achieved filler content of 18% and a fiber content of 5.5%, which gives complete, the solids content of 23.5% and the content of organic material 23%, calculated on the solids content. This slurry paint was processing at the facility for supercritical water oxidation without any difficulties.

Samples of secondary filler of the same type that was used in the field experiment on the paper machine, were treated in a magnetic separator, high gradient. This treatment allowed us to improve the degree of whiteness to 3.5% ISO.

Were also conducted experiments for the specified filler using a bleaching dithionite. This treatment has improved the whiteness of 1-2% ISO.

Claims

1. Method for continuous extraction of inorganic material from the pulp of the dye obtained as waste material recovery secondary fiber from recycled paper, comprising the following operations: (a) control and/or regulating the proportions of organic material in the form of fibrous mavadi in the pulp paint so that the solid content becomes equal to 10-35%, and regulation in the operation (a) and operation (b) is conducted with respect to each other so that the slurry paint suitable for pumping by the pump; (c) increasing the pressure of the pumped slurry paint until at least 22 MPa; (d) increasing the temperature of the pumped slurry paint to supercritical or almost supercritical temperature; (e) adding to the slurry paint containing oxygen environment in a quantity sufficient to oxidize all organic material, at supercritical temperature and pressure in the reactor; (f) recovery released during the oxidation of organic material energy in a suitable form, and (g) the division of flow of the material of which was allocated to energy and which contains the specified inorganic material, gases and water, and the specified separation of material involves the extraction of valuable inorganic material.

2. The method according to p. 1, characterized in that the amount of organic material in the operation (a) is 15-30%.

3. The method according to one of paragraphs.1 and 2, characterized in that the operation (a) and (b) adapt to each other so that after the operation (b) pulp paint has a content of chemically potrebi is in operation (d) a temperature increase of no more than 425C.

5. The method according to one of paragraphs.1-4, characterized in that the temperature in the reactor after operation (e) is not more than 650C.

6. The method according to p. 5, characterized in that the temperature in the reactor ranges from 500 to 600C.

7. The method according to one of paragraphs.1-6, characterized in that the gaseous reaction products are separated from the material flow in the operation (g) and released into the atmosphere or accumulate.

8. The method according to p. 7, characterized in that the accumulated gases to remove carbon dioxide.

9. The method according to one of paragraphs.1-8, characterized in that the pulp ink is subjected to leaching earlier transaction (s).

10. The method according to p. 9, characterized in that the slurry paint after this wash has a salt content of not more than 1000 parts per million.

11. The method according to one of paragraphs.1-10, characterized in that the oxidation time in the reactor is about 10 min or less, mostly about 5 min or less and most preferably about 1 min.

12. The method according to one of paragraphs.1-11, characterized in that the fibrous material is removed from the pulp paint to get its content at the level indicated in the operation (a), by flotation, sedimentation, vortex cleaning, sieving, centrifugation or commnity material is removed from the pulp paint to get its content level, specified in the operation (a), by flotation, sedimentation, vortex cleaning, sieving, centrifugation, or a combination of two or more of these technologies, which are integrated in the process of removing ink from paper.

14. The method according to one of paragraphs.12 and 13, characterized in that the remote fibrous material extracted recycled fiber.

15. The method according to one of paragraphs.1-11, characterized in that the fibrous material is removed from the pulp paint to get its content at the level indicated in the operation (a), using aerobic or anaerobic biological decomposition of part of the fibrous material, and conversion of part of the fibrous material into ethanol using enzymatic or other type of hydrolysis followed by fermentation, as well as when using the combination of two or more of these technologies.

16. The method according to one of paragraphs.1-15, characterized in that the water content during the operation (b) is adjusted by means of sedimentation, vortex purification, centrifugation, pressing in a suitable press, as well as when using the combination of two or more of these technologies.

17. The method according to one of paragraphs.1-16, characterized in that the operation (g) neorganicheskiye).

18. The method according to one of paragraphs.1-17, characterized in that the operation (g) an inorganic material is subjected to final processing to improve the degree of whiteness by 2% or more.

19. The method according to p. 18, wherein the final processing involves cleaning to remove reducing the degree of whiteness of the metal oxides and/or tooth whitening using bleaching agents.

20. The method according to one of paragraphs.1-19, characterized in that the extracted valuable inorganic material contains a pigment, the particles of which are smaller than the particles of the filler, and the inorganic material is separated into a fraction of filler and pigment fraction.

21. The method according to one of paragraphs.1-20, characterized in that the energy in the operation (f) Recuperat in the form of steam and/or hot water.

22. The method according to one of paragraphs.1-21, characterized in that the incoming pulp paint has a solids content that is less than 8% to dehydration, and has a content of organic material, which is over 35%, and the balance is an inorganic material, in terms of solids content.

 

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