BR102013016060B1 - Dry and wet processes of recovery, processing and reuse of dreg residue generated in the pulp industry and products obtained through them - Google Patents

Description

DRY AND WET PROCESSES FOR RECOVERY, BENEFIT AND RECOVERY OF DREGS WASTE GENERATED IN THE CELLULOSE INDUSTRY AND PRODUCTS OBTAINED THROUGH THE SAME

The present invention relates to dry and wet processes for the recovery, processing and reuse of dreg waste generated in the pulp industry and the product obtained from it, which belongs to the chemical sector, particularly it is a process to recover , benefit, reuse and apply dreg residues generated in the pulp manufacturing process, specifically generated in the black liquor from the recovery boiler - dregs.

TECHNICAL BACKGROUND The classification of waste generated in the manufacturing industry has reached huge volumes in recent years and the concern for the environment has been even greater.

According to the new trends of the productive world market, we can consider that companies that transform noble raw materials into finished consumer products should be self sustainable, that is, giving proper destination to their generated waste and not destining them to landfills and not even for applications that may compromise the environment.

DREGS Feature

DREGS residues are currently considered a major problem for the pulp industry due to the high content of contaminants, among them sodium and high carbon, as well as some metals and ametals. liquid, ie in suspension. This makes it even more difficult to dispose of because the solids content of this residue is very low and the soluble content is relatively high.

Its classification as a waste is of high safety and a hazardous contaminant, however, it requires extremely targeted and rigorous work for its application. The high carbon content contained in its composition is a high risk factor for the environment and the possibility of contamination in the production system is high due to its easy dispersion in aqueous medium.

In the last 50 years the pulp industry has generated this waste and so far the most common applications of this waste have been mixing it together with the calcium carbonate sludge generated in the caustification where it is also destined for landfill being diluted. in large proportions on landfills.

According to the results obtained and large-scale generations Dregs has in its composition a carbon content of around 55%, approximately 20 to 25% free sodium, approximately 15% sodium sulfite and approximately 5% free sulfur. . The world market has been very strict with the control of disposal of this waste, in particular due to its high contaminant content in expressive volumes, close to 100 thousand tons per year.

Aiming at the continuous improvement of the pulp production system and the environmental preservation, as well as the sustainability of the pulp process, the claimed processes aim to recover, benefit, reuse and apply the dreg residues generated in the pulp manufacturing process, specifically generated. in the black liquor from the recovery boiler the dregs.

Thus, the present invention aims to recover 100% of the dregs by transforming the waste into prime material for consumer product applications. BRIEF DESCRIPTION OF THE INVENTION The present invention provides the dry and wet processes for recovering, processing and reusing dreg waste. The dry process comprises the steps of: preparing dreg sludge with the addition of additives; drying; milling; classification; transport; storage and bagging. And the wet process comprises the steps of: preparation of dreg sludge with addition of additives; sieving; milling and storage.

Due to the high carbon content and especially the sodium contained in this residue, the reaction obtained by drying in rotary dryers with temperatures up to 180 ° C form the pelletization of the particles, a physical-mechanical phenomenon that occurs due to the insertion of dry and ground dregs. added to the agglutination polymer.

At the end of drying and pelletizing the material achieves a powder and fluid characteristic very similar to black smoke, a raw material widely used in the steel industry, in continuous casting systems of steel making. The generated product can also be applied in the manufacture of bitumen, asphalt, vulcanization rubber and melt in the steel industry.

Also in the recovery system of this residue can be achieved a material in liquid form where the final product is wet milled and its application becomes viable for use as a pigment for paints, waterproofing blankets for slabs and sealing agents. raw material for such applications.

DETAILED DESCRIPTION OF THE INVENTION The dry process of recovering, processing and reusing dreg waste generated in the pulp industry comprises the following steps: a. - Preparation of Dregs al. - the dregs sludge is received in the form of mud and is conducted between 500 - 1000 kg / hour to a rotary wood oven that generates heat by burning it in the main furnace reaching a temperature of 280 - 380 ° C; B. - Pelletizing and drying bl.- The step of pelletizing and drying of the dreg begins. While drying, the concentration of the particles is also performed by adding 0.8 - 1.2% of a starch-based binder which may be from the group. which consists of corn or manioc starch. The binder is applied as a cloud through the spray nozzle in the mouth of the dryer, forming a film and through the heat generated by the burner, the material forms an uneven yet moist layer of lump with approximately 10% humidity, that is. the pelletizing phase where thermal shock forms these pellet clumps. For a good particle pelletizing efficiency that occurs in the drying process due to the high carbon content of the medium, ie when receiving heat the material is high in moisture and due to thermal shock and low particle size the same. create a nucleus between them forming a cluster called pelletizing; ç. - Grinding cl.- Then 40% of the total volume of the still heated ball mill is added with the stones formed in the previous step which are discharged and ground together with the average sized dregs around 10 microns for 60 -80 minutes. , once again the pelletization process begins, because the sodium contained in it aggregates in the carbon due to the high surface tension of the particles and the ground limestone adheres to these particles forming a compound very similar to cement; d. - Classification and conveying dl.- After grinding the compost goes through the grading system on vibrating screens with openings of 40 - 80 mesh to retain the larger unground particles that will return to the previous stage and what has been ground is sent to a endless thread feeding a storage silo, at this time 1% of the volume of calcium stearate type flow agent is added, which has as its main function to maintain the flowability of the generated powder compound; and. - Bagging el.- The material stored in the silo is bagged in big bag or 30kg bags. The product obtained by the process described above comprises the following characteristics: Appearance - pellet fluid powder Moisture - maximum 1% Carbon content - minimum 50% Free sodium content - minimum 10% CaC03 content - minimum 20% Si02 content - maximum 3% Sulfur content - maximum 5% Particle size - 100% less than 10 microns.

Chemical analysis of dregs formation as per annex 1. The wet process of recovery, beneficiation and reuse of dregs residues generated in the pulp industry comprises the following steps: a.- Dregs sludge preparation al.- The material is received in the form sludge and transferred to a dispersing-type mixing tank that receives 30% water as a carrier and 0.2% dispersant (sodium polyacrylate) and 015% calcium stearate on solids content to maintain viscosity between 200 to 300 cps; a2. The material is stirred for 20 to 30 minutes for stability and homogenization of the sludge with 50 to 65% solids content. B. - Screening bl.- After dispersion the material is sieved # 200 mesh and transferred to grinding. ç. - Grinding cl.- After screening the material is transferred to a vertical mill with zirconia or alumina spheres to reduce the average particle size by 0.6 - 1.0 micron which is achieved with a residence time between 100 -120 minutes. d. - Stocking dl. - After grinding the material is sent to storage tanks and packed in pails. The product obtained by the process described above comprises the following characteristics: Appearance - suspended black liquid Moisture - 30% Carbon content - 50% minimum Free sodium content -10% minimum CaC03 content -20% minimum Si02 content - 3% minimum Particle size - 1 micron average The final product is sold to paint and related industries and to the waterproofing additive processing industries.

EXAMPLE OF OBTAINMENT The following is an example of application of the invention to illustrate practical viability. It is presented in sufficient detail so that a knowledgeable subject matter expert can easily reproduce it.

This example does not imply limiting the scope of the invention.

Example of obtaining a product through the dry process of recovery, processing and reuse of dreg residues generated in the pulp industry: a. - Preparation of Dregs al.- sludge 5000 kg of mud-dregs are received, which is conducted at 700 kg / hr to a 300 ° C rotary wood-fired oven; B. - Pelletizing and drying bl. 1.0% cornstarch-based binder is added. bl.- the dreg pelletizing and drying step is initiated and while drying the concentration of the particles is also performed by adding 1.0% of a cornstarch-based binder; ç. - Grinding cl.- the pelleted dreg is sent at 700 kg / hour to a ball mill filling a 40% volume for 60 minutes to reach an average size of 5 microns; d. - Classification and transportation dl. - After milling in the ball mill, the compost passes through the grading system on vibrating sieves with openings from 40 to 80 mesh and 1% of the calcium stearate flow agent volume is added to the packaging silo; and. - Bagging el.- The material stored in the silo is bagged in 30kg bags.

RESULTS OBTAINED The product obtained has the following characteristics: Appearance - pellet fluid powder Moisture - 1% Carbon content - 50% Free sodium content - 10% CaC03 content - 20% Si02 content - 3% Sulfur content - 5% Particle size - 100% smaller than 10 microns.

Example of obtaining a product through the wet process of recovery, beneficiation and reuse of dreg residues generated in the pulp industry: a. - Preparation of Dregs sludge al.- The material is received in sludge form and transferred to a disperser-type mixing tank which receives 30% water as carrier and 0.2% dispersant (sodium polyacrylate) and 015% calcium stearate on solids content to maintain viscosity between 200 to 300 cps; a2. - The material is stirred for 20 minutes for stability and homogenization of the 60% solids slurry. B. - Screening bl.- After dispersion the material is sieved # 200 mesh and transferred to grinding. ç. - Grinding cl. - After screening the material is transferred to a vertical mill with zirconia or alumina balls to reduce the average particle size by 0.6 - 1.0 micron which is achieved with a residence time of 120 minutes. d. - Storage dl.- After grinding the material is sent to storage tanks and packed in drums.

RESULTS OBTAINED The product obtained has the following characteristics: Appearance - suspended black liquid Moisture - 30% Carbon content - 50% minimum Free sodium content -10% minimum CaC03 content -20% minimum Si02 content -3% minimum Size Particle size - 1 micron average INDUSTRIAL APPLICATION OF THE PRODUCT OBTAINED - Steelmaking - Used in the continuous casting system as a high performance compound due to the high carbon content and as a fluxing aid during casting of steel. The material fuses with the high temperature of the still liquid steel forming a film under the ingot surface giving strength and maintaining the high melting temperature of the steel due to free sodium, thereby increasing the strength quality of the cast steel. - Rubber - Due to the high carbon content, it guarantees excellent vulcanization in the formation of rubber and because it is a medium load material such as limestone, it maintains the mechanical resistance of the rubber produced. - Automobile Rubber Coating - Same as the application of rubber with improvement in the alloy of the inner lining of the plates and the floor in the underside of the automobiles. - Bakelite - Great bakelite former due to its excellent carbon composition, mineral filler and flux component. - Exothermic gloves, exothermic plates and flux powders for the steel industry. - Bitumen, asphalt, waterproofing blanket.

Ingot based paints, asphalt paints, bituminous waterproofing.

ADVANTAGES OBTAINED WITH 0 INVENT

With the process of recovery, processing and reuse of dreg waste generated in the pulp industry and product obtained through it, they offer the following extraordinary advantages: - Continuous improvement of the pulp industry production system; - environmental preservation; and - Sustainability of the pulp process. The scope of the present invention should not be limited to the example but to the terms defined in the claims and their equivalents.

Claims (6)

1. - DRY PROCESS FOR RECOVERY, BENEFIT AND RECOVERY OF DREGS WASTE GENERATED IN THE CELLULOSE INDUSTRY, characterized by the following steps: a. - Preparation of Dregs al. - dreg sludge is received in the form of sludge and is conducted between 500 - 1000 Kg / hour to a rotary wood oven and generates heat by burning it in the main furnace to a temperature of 280 - 380 ° C; B. - Pelletizing and drying bl.- The stage of pelletization and drying of the dreg begins. While drying, the concentration of the particles is also performed by adding 0.8 - 1.2% of a starch-based binder which is applied as a drying agent. cloud through the spray nozzle in the mouth of the dryer, forming a film and through the heat generated by the burner, the material forms an uneven yet moist layer of lump with approximately 10% humidity; ç. - Grinding cl.- Then 40% of the total volume of the still heated ball mill is added with the stones formed in the previous step which are discharged and ground together with the average sized dregs around 10 microns for 60 80 minutes; d. - Classification and conveying dl.- After grinding the compost goes through the grading system on vibrating screens with openings of 40 - 80 mesh to retain the larger unground particles that will return to the previous stage and what has been ground is sent to a endless thread that will feed a storage silo at this time and add 1 l of the volume of flow agent; and. - Bagging el.- The material stored in the silo is bagged in a big bag or in 30kg bags. 2. Drying process for the recovery, improvement and reuse of the waste generated from the cellulose industry DREGS according to claim 1, characterized in that the binding agent is based on maize or cassava starch. 3. Drying process for the recovery, improvement and reuse of the DREGS waste generated in the cellulose industry according to claim 1, characterized in that the flow agent is of the calcium stearate type. 4. - PRODUCT, characterized in that it is obtained by the process as claimed in 1, and has the following characteristics: Appearance - pellet fluid powder Moisture - 1% maximum Carbon content - 50% minimum Free sodium content - 10% minimum CaC03 content - 20% minimum Si02 content - 3% maximum Sulfur content - 5% maximum Particle size - 100% less than 10 microns. 5. Wet process for the recovery, improvement and reuse of the waste generated from the cellulose industry DREGS, characterized by the following steps: a.- Preparation of the Dregs sludge. a disperser-type mixing tank that receives 30% water as a carrier and 0.2% dispersant (sodium polyacrylate) and 015% calcium stearate on solids content to maintain viscosity between 200 to 300 cps; a2. The material is stirred for 20 to 30 minutes for stability and homogenization of the sludge with 50 to 65% solids content. B. - Screening bl. - After dispersion the material is sieved # 200 mesh and transferred to grinding. ç. - Grinding cl. - After screening the material is transferred to a vertical mill with zirconia or alumina balls to reduce the average particle size by 0.6 - 1.0 micron which is achieved with a residence time of 100 - 120 minutes. d. - Storage dl.- After grinding the material is sent to storage tanks and packed in drums. 6. PRODUCT, characterized in that it is obtained by the process as claimed in 5, and has the following characteristics: Appearance - suspended black liquid Moisture - 30% Carbon content - 50% minimum Free sodium content -10% minimum of CaC03 -20% minimum Si02 content -3% minimum Particle size - average 1 micron.