TAPPI proceedings of the 1988 pulping conference; 1988 October 30-November2; New Orleans, LA. Atlanta, GA: TAPPI Press; 1988: Book 3.
|
|
- Terence Barber
- 5 years ago
- Views:
Transcription
1 TAPPI proceedings of the 1988 pulping conference; 1988 October 30-November2; New Orleans, LA. Atlanta, GA: TAPPI Press; 1988: Book 3. PROGRESS IN BLEACHING PULPS WITH THE SULFITE-AIR SYSTEM Edward L. Springer JamesD.McSweeny Chemical Engineer Chemist USDA Forest Service. USDA Forest Service. Forest Products Forest Products Laboratory. 1 Laboratory1 Madison, WI Madison, WI U.S.A. U.S.A. ABSTRACT The effects of pulp pretreatment. pulp consistency. and quantity of sulfite added on final pulp brightness were studied using the cupric ion catalyzed sodium sulfite-air bleaching system. Aspen kraft pulp that had been partially delignified by chlorination and alkaline extraction was used. Highest brightnesses were attained by pretreating the pulp with cupric ion and by using the highest practical consistency. Brightness increased. but at a decreasing rate, with increases in added sulfite. A search was made for other catalysts. Nickelous ion vas found to be effective. but not quite as good as cupric ion. Spruce and aspen kraft pulps. partially delignified by an oxygen treatment. were easily brightened to semibleached levels using the cupric ion catalyzed sodium sulfite-air system. These results indicate that a chlorine-free bleaching system may be feasible. KEYWORDS Bleaching, Kraft pulp, Sodium sulfite, Copper sulfate.. Nickel sulfate. Populus tremulaides, Picea mariana, Oxygen delignification. 1This article was written and prepared by U.S. Government employees on official time, and it is therefore in the public domain and not subject to copyright. The Forest Products Laboratory is maintained in cooperation with the University of Wisconsin. INTRODUCTION Effluent from the bleach plant is the major source Of pollution from pulpmills that produce bleached kraft pulp (1). Chlorine. hypochlorite. and chlorine dioxide, used in bleaching. react with lignin and other pulp constituents (such as fatty and resin acids) to produce chlorinated organic compounds. Some of these compounds are toxic and mutagenic and are thus harmful to living organisms (1). Significant quantities of these compounds pass through pulpmill waste water treatment systems and are expelled into receiving waters. Because of their harmful effect on the environment. the Swedish and West German govements have restricted the quantities of these materials that can be discharged from their mills. In the near future. the United States will probably also restrict discharges of these materials. A large reduction in the output of chlorinated organic compounds from the bleach plant can be achieved by use of an oxygen delignification Stage after pulping. Complete elimination of these compounds would require the elimination of all chlorine containing oxidants from the bleaching sequence. If chlorine containing compounds were absent from the bleach plant, countercurrent pulp washing all the way back to black liquor recovery could be practiced. thus eliminating all bleach plant effluent. This research is part of an effort to replace chlorine. hypochlorite. and chlorine dioxide in the final stages of bleaching with a suitable nonchlorine oxidizing agent. Our objectives were to optimize the conditions for sulfite-air bleaching of a partially delignified pulp and to demonstrate that oxygendelignified hardwood and softwood pulps can be effectively bleached. SIMULTANEOUS OXIDANT GENERATION AND USE Previously, it was reported that a chlorinated, alkaline-extracted aspen kraft pulp could be bleached by slowly adding a dilute slurry of calcium sulfite to a well-aerated suspension of the pulp (2). However, it was found necessary to first pretreat the pulp with a dilute solution of cupric sulfate. to satisfy its ion exchange capacity, and also to have a trace of cupric ion present in the pulp suspension to act as a catalyst. After extensive testing. this calcium sulfite-air bleaching system was found to be very difficult to control. At times efficient bleaching could be achieved with large increases in brightness: at other times essentially no bleaching occurred under what seemed to be identical reaction conditions. To date. the factor or factors responsible for this variability have not been identified. Because of this problem, all recent work has been done using sodium sulfite. The sodium sulfite-air system has been found to be very easy to control with consistent results obtained repeatedly. This may be due, in part, to the fact that sodium sulfite is added to the reactor as a solution. whereas calcium sulfite (being quite insoluble) is added as a suspended solid. The sodium sulfite-air system was used in studying the effects of pulp consistency (in the reactor). pulp pretreatment. and quantity of sulfite added on the brightness level attained. A chlorinated. alkalineextracted aspen kraft pulp (Kappa No. 6) was used in this work. All Pulp samples were treated after bleaching by soaking them for 4 min in a 0.015% solution of sulfuric acid at a consistency of 1.2%. EFFECT OF PULP CONSISTENCY Three consistency levels, 0.4%, 1.2%, and 2.4%, were studied. Fig. 1 shows the effects of quantity of added sulfite and of pulp consistency on the final bleached brightness. As the amount of added sulfite increased. the brightness increased. but at a decreasing rate. This is similar to the effect of other bleaching agents. For a given level of sulfite added. increasing the consistency increased the brightness level attained. The highest consistency level studied. 2.4%, was at or near the highest level at which efficient mixing could be achieved in the present reactor system. EFFECT OF PULP PRETREATMENT 1988 Pulping Conference / 741
2 For each consistency level, the pulp pretreatment used. if any. is designated on Fig. 1 by the type of symbol. As in the previous work. some samples of the pulp were pretreated by soaking overnight at 1.0% consistency in a 0.10% solution of cupric sulfate. They were then washed with distilled water before bleaching with the sodium sulfite-air system. The purpose of this pretreatment was to replace the cations on the ion exchange sites of the pulp with cupric ions so that the cupric ions added to the solution in the reactor to catalyze the production of oxidant (peroxymonosulfate) would remain in solution and not be deactivated by being bound to the pulp. To investigate the possibility of avoiding this pretreatment step, samples of unpretreated pulp were placed in the reactor, and an adequate amount of cupric sulfate was added to satisfy both the ion exchange capacity of the pulp and the catalyst requirement. These pulps were then bleached with the sodium sulfite-air system in the same manner as were the cupric ion pretreated pulps. In addition. some samples of the unpretreated pulp were pretreated with acid prior to bleaching. The acid pretreatment procedure was a 15-min soak at 1.2% consistency in a 0.010% sulfuric acid solution. As with the unpretreated pulps. prior to bleaching, sufficient cupric sulfate was added to the solution in the reactor to satisfy both the ion exchange capacity of the acid pretreated pulp and the catalyst requirement. In a previous study on bleaching with potassium peroxymonosulfate. acid pretreatment of pulp was shown to increase the final brightness attained (3). We thought that a similar effect might be observed with the present system. Although the data showed considerable scattering. especially at the 0.4% consistency level, there appeared to be no significant difference in brightness level attained between the acid pretreated pulps and those that had not been pretreated. Pulps pretreated with cupric ion seemed to attain significantly higher brightness levels than the other pulps. This was especially apparent at the 1.2% consistency level. Adding cupric ion to the reactor was apparently not quite as effective as soaking the pulp overnight in a cupric ion solution. Thus. at a given level of sulfite addition, maximum pulp brightness was attained by using the highest possible consistency in the reactor and by pretreating the pulp with a cupric ion solution. EFFECT OF SULFITE CATION The cation associated with the sulfite anion could possibly have a significant effect on bleaching results. The best previously obtained calcium sulfite data for 1.2% Consistency (2) are compared with the present sodium sulfite data an Fig. 1. The calcium sulfite bleached pulps had been pretreated with cupric ion. There seemed to be no significant differences between the sodium sulfite and the calcium sulfite data. These data were, however, taken at different ph levels in the reactor. When employing calcium sulfite. the reactor ph was decreased during the run from 9.0 to 8.5 (2). When using sodium sulfite. the reactor ph was held steady at For both systems. reactor temperature was 50 C. An ammonium sulfite trial run gave very poor results. however. the 742 / TAPPl Proceedings reaction conditions had not been optimized. other sulfites have not been tried. EFFECT OF CATALYST To date, Contrary to expectations. some brightness increase could be attained without an oxidant-generating catalyst present in the system. Figure 2 shows the cupric ion catalyzed. unpretreated. and acid pretreated data for 0.4% and 1.2% Consistency together with similar data taken where no catalyst was present in the reactor. At a consistency of 0.4%, substantial brightness increases (up to 17 percentage points) could be obtained without a catalyst present, however, large quantities of sulfite were needed to obtain these increases. These brightness increases may have been due to sulfonation and subsequent solubilization and removal of lignin from the pulp. Watanabe and coworkers (4) found that an acid hydrolysis lignin could be sulfonated and solubilized at low temperatures (70 C) under conditions very similar to those used in our research. It appears that two mechanisms may be acting simultaneously to increase the pulp brightness in the cupric ion catalyzed system: (1) lignin sulfonation and solubilization and (2) lignin oxidation by the generated = peroxymonosulfate anion (SO5 ) with subsequent partial solubilization. On the basis of sulfite consumption per percentage point brightness increase, the sulfite is much more efficiently utilized in the catalyzed system. Although the cupric ion (Cu ++ ) may be found to be the most efficient catalyst. it was suspected that other metal ions (such as Ni ++, Mn ++. Co ++, Zn ++ ) might also be effective as catalysts. To date, we have only studied the use of the nickelous ion as a catalyst. As was done with the cupric ion pretreatment, the pulp was pretreated with nickelous ion by soaking overnight at 1.0% consistency in a 0.10% solution of nickelous sulfate. The pulp was then thoroughly washed with distilled water before bleaching. A dilute solution of nickelous sulfate was added to the reactor so that the concentration of nickelous ion during simultaneous generation and bleaching was 4.0 x 10-5 M. This was the same concentration as was used when cupric ion was the catalyst. The results from the initial trials at 1.2% consistency using nickelous ion are compared with the cupric ion pretreated. cupric ion catalyst results in Fig. 3. For the conditions used. nickelous ion (Ni ++ ) was somewhat less effective than cupric ion. Further work will be done using Ni ++ and other potential catalysts. Metal ion catalysts, such as Cu ++ or Ni ++, have the disadvantage that they are exchanged for the sodium (Na + ) or hydrogen (H + ) ions associated with the carboxyl groups (and other ion exchanging groups) of the pulp and are thus depleted from the reaction solution. The pulps ion exchange capacity must. therefore, be satisfied prior to reaction. This requires a substantial quantity of metal ion. too much to be thrown away or wasted. It would be better to use a catalyst that did not interact with the ion exchanging groups of the pulp. We plan to seek such a catalyst. If the cupric ion (or some other metal ion) proves to be the most effective catalyst. it will be necessary to recover it from the bleached pulp for reuse. In
3 most laboratory work and on the commercial scale, bleached pulps are acidified with aqueous sulfur dioxide or bisulfite as the last step in the bleaching process. In our work on the sulfite-air system, we have found dilute sulfuric acid to be as effective as bisulfite in this step. Treating a cupric ion catalyzed sulfite-air bleached pulp with acid will displace the cupric ions on the pulp with hydrogen ions and yield a dilute, low-ph solution of cupric ions. If the solution is then drained from the pulp and its ph is adjusted to near neutral with a base (such as sodium carbonate or sodium hydroxide). it can then be used to pretreat a fresh batch of unbleached pulp. Pulp placed in the solution will exchange its sodium or hydrogen ions for the cupric ions in solution. and these ions will be removed from the solution. The solution can then be drained from this batch of pulp and sent on to the recovery cycle. Using this procedure. the cupric ions could be recycled indefinitely. Some losses would undoubtedly occur. and some makeup copper sulfate would be required. however. cupric ion recycle would probably be both technically and economically feasible. The major bleaching costs for the sulfite-air method would thus be the cost of the sulfite and the capital cost of the bleaching reactor and auxiliary equipment. Sodium and calcium sulfites may soon be available at a very low cost, because they are waste materials from certain processes for scrubbing of sulfur dioxide from power plant flue gases for the control of acid rain. BLEACHING OXYGEN-DELIGNIFIED KRAFT PULPS The work described so far has involved the effect of reaction conditions on the bleaching of a chlorinated. alkaline-extracted, aspen kraft pulp. It was. of course. of great interest to investigate the sulfite-air bleaching of oxygen-delignified kraft pulps. Cupric ion pretreated. oxygen-delignified spruce and aspen kraft pulps were bleached using the cupric ion catalyzed, Sodium sulfite-air system. The results from these bleaching experiments together with previous results from bleaching the cupric ion pretreated, chlorinated, alkaline-extracted, aspen kraft pulp are shown in Fig. 4. In all experiments. pulp consistency in the reactor was 1.2%. As can be seen. the sulfite-air bleaching system is effective in bleaching both hardwood and softwood oxygendelignified kraft pulps. This finding opens up the possibility of developing a completely chlorine-free bleaching process for kraft pulps. A two-stage oxygen. sulfite-air bleaching sequence might be both technically and economically feasible for producing semibleached pulps. With further study. it may be possible to attain higher levels of brightness. It appears that much further effort will be required to develop the sulfite-air bleaching method into a reliable industrial process. CONCLUSIONS To obtain maximum brightness increases when using the sodium sulfite-air system, delignified kraft pulps must be pretreated with cupric ion, and a cupric ion catalyst must be present in the reactor. The highest Practical pulp consistency must also be employed. With this system, an oxygen-delignified spruce kraft pulp has been bleached to a brightness of 75% and an oxygen-delignified aspen kraft pulp to a brightness of 82%. EXPERIMENTAL The reactor employed in this work was identical to that used previously (2). It consisted of a 500-ml Pyrex 2 glass beaker containing a fritted glass gas sparging tube and a motor-driven impeller. Temperature, ph, and rate of sulfite addition were carefully controlled. The usual reaction conditions employed are listed below. 2The use of trade or firm names in this publication is for reader information and does not imply endorsement by the U.S. Department of Agriculture of any product or service. Weight of pulp (ovendry basis) 1.3, or 6 g 3 Initial weight of pulp and water 250 g Concentration of Na 2SO 3 solution 5.0 g/1 Rate of addition of Na 2SO 3 solution 30 ml/h Air rate ph 12.1 CuSO 4 added 2,000 ml/min Cu ++ pretreated pulp 1.6 mg H + or unpretreated pulp 16.0 mg Reaction temperature 50 C Delignification of Kraft Pulps Aspen (Populus tremuloides Michx.) kraft pulp, yield 55%, Kappa No. 14, was chlorinated and alkaline extracted as follows: The pulp was reacted with 1.3% chlorine (on dry pulp) at 2% consistency and 25 C for 60 min. Then it was washed and extracted with 2.0% sodium hydroxide at 10% consistency and 60 C for 60 min. Finally. it was thoroughly washed with 70 C water, and then washed with distilled water, and filtered to about 25% consistency. Final Kappa No. was 6. The same sample of aspen kraft pulp was oxygen delignified in a Parr reactor under the following conditions: 3 Depending upon consistency desired Pulping Conference/743
4 Consistency 1.6% NaOH MgSO 4 Total pressure (oxygen+vapor) 2.0% (on dry pulp) 0.5% (on dry pulp) 129 lb/in 2 -gauge Temperature 100 C Time at 100 C 60 min. It was then thoroughly washed and filtered as before. Final Kappa No. was 7. Spruce (Picea mariana) kraft pulp, yield 50%. Kappa No. 30, was oxygen delignified in a Parr reactor under the following conditions: Consistency 1.6% ML Figure 1. Effects of pulp pretreatment, consistency. sulfite anion, and quantity of sulfite added on pulp brightness. (ML ) NaOH MgSO 4 Total pressure (oxygen+vapor) 10.0% (on dry pulp) 0.5% (on dry pulp) 120 lb/in 2 -gauge Temperature 125 C Time at 125 C 90 min. It was thoroughly washed and filtered as were the aspen pulps. Final Kappa No. was 9. Determination of Brightness Handsheets were formed on No. 595 Schleicher and Schuell filter paper in a 100-m Buchner funnel. Brightnesses were determined with a Beckman Model B spectrophotometer with a reflectance attachment. Magnesium carbonate, the standard, was set at 100%. LITERATURE CITED ML Figure 2. Comparison of catalyzed and uncatalyzed bleaching. (ML ) 1. R. Brannland and G. Fossum. How to cope with TOCl, Proceedings 1987 TAPPI Pulping Conference. p , Washington. DC, Nov. 1-5, E. L. Springer and J. D. McSweeny. Use of calcium Sulfite and air to bleach a delignified aspen kraft pulp. Tappi 69(4): 129 (1986). 3. E. L. Springer and J. D. McSweeny. Bleaching groundwood and kraft pulps with potassium peroxymonosulfate. Proceedings 1986 TAPPI Pulping Conference. p , Toronto, ON, Oct , M. Watanabe, M. Sakumato, G. Meshitsuka, and J. Nakano. Radical sulfonation of lignin-water solubilization of acid hydrolysis lignin. Fourth International Symposium on Wood and Pulping Chemistry, Vol. 1, p , Paris, April 27-30, ML / TAPPI Proceedings Figure 3. Comparison of cupric ion (Cu++) and nickelous ion (Ni++) catalyzed bleaching. (ML )
5 ML Figure 4. Comparison of the bleaching of oxygen-delignified spruce and aspen kraft pulps with that of chlorinated and alkaline-extracted aspen kraft pulp. (ML ) 1988 Pulping Conference / 745
Draw one line from each solution to the ph value of the solution. Solution ph value of the solution
1 The ph scale is a measure of the acidity or alkalinity of a solution. (a) Draw one line from each solution to the ph value of the solution. Solution ph value of the solution 5 Acid 7 9 Neutral 11 13
More informationCALCIUM HYDROXIDE AS AN ALTERNATIVE ALKALI FOR THE OXYGEN BLEACHING STAGE OF KRAFT PULP
CELLULOSE CHEMISTRY AND TECHNOLOGY CALCIUM HYDROXIDE AS AN ALTERNATIVE ALKALI FOR THE OXYGEN BLEACHING STAGE OF KRAFT PULP K. DÖLLE and B. BAJRAMI State University of New York (SUNY), College of Environmental
More informationDOUBLE DISPLACEMENT REACTIONS. Double your pleasure, double your fun
DOUBLE DISPLACEMENT REACTIONS Double your pleasure, double your fun Industrial processes produce unwanted by-products. Dissolved toxic metal ions-copper, mercury, and cadmium-are common leftovers in the
More informationEFFICIENCY AND EFFLUENT CHARACTERISTICS FROM Mg(OH) 2 -BASED PEROXIDE BLEACHING OF HIGH-YIELD PULPS AND DEINKED PULP
CELLULOSE CHEMISTRY AND TECHNOLOGY EFFICIENCY AND EFFLUENT CHARACTERISTICS FROM Mg(OH) 2 -BASED PEROXIDE BLEACHING OF HIGH-YIELD PULPS AND DEINKED PULP CÉLINE LEDUC, JOANNIE MARTEL and CLAUDE DANEAULT
More informationPOM-ASSISTED ELECTROCHEMICAL DELIGNIFICATION AND BLEACHING OF CHEMICAL PULP
CELLULOSE CHEMISTRY AND TECHNOLOGY POM-ASSISTED ELECTROCHEMICAL DELIGNIFICATION AND BLEACHING OF CHEMICAL PULP HÉLÈNE LAROCHE*, MOHINI SAIN**, CARL HOUTMAN*** and CLAUDE DANEAULT* *Pulp and Paper Research
More informationDefinition 1 An element or compound is oxidized when it gains oxygen atoms
Oxidation and Reduction Part I Learning Outcomes 1. Introduction to oxidation and reduction: simple examples only, e.g. Na with Cl 2, Mg with O 2, Zn with Cu 2+. 2. Oxidation and reduction in terms of
More informationUNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS General Certificate of Education Advanced Subsidiary Level and Advanced Level
UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS General Certificate of Education Advanced Subsidiary Level and Advanced Level *4827396477* CHEMISTRY 9701/35 Advanced Practical Skills October/November
More informationT 282. WORKING GROUP CHAIRMAN Junyong Zhu SUBJECT
NOTICE: This is a DRAFT of a TAPPI Standard in ballot. Although available for public viewing, it is still under TAPPI s copyright and may not be reproduced or distributed without permission of TAPPI. This
More informationAlpha-, beta- and gamma-cellulose in pulp. 1. Scope
T 203 om-93 TENTATIVE STANDARD 1931 OFFICIAL STANDARD 1932 REVISED 1974 OFFICIAL TEST METHOD 1983 REVISED 1988 CORRECTION 1992 REVISED 1993 1993 TAPPI The information and data contained in this document
More informationCambridge International Examinations Cambridge International Advanced Subsidiary and Advanced Level
Cambridge International Examinations Cambridge International Advanced Subsidiary and Advanced Level *9763634822* CHEMISTRY 9701/36 Paper 3 Advanced Practical Skills 2 October/November 2014 2 hours Candidates
More informationPeracetic Acid Bleaching CH CO H
Peracetic Acid Bleaching CH 3 CO 3 H Introduction of Bleaching Bleaching is a chemical decoloration and delignification process carried out on various types of pulp. Dli Delignification ifi i Removal of
More informationCambridge International Examinations Cambridge International Advanced Subsidiary and Advanced Level
Cambridge International Examinations Cambridge International Advanced Subsidiary and Advanced Level CHEMISTRY 9701/31 Paper 3 Advanced Practical Skills 1 May/June 2014 2 hours Candidates answer on the
More informationSUBSTITUTION OF SODIUM HYDROXIDE WITH MAGNESIUM HYDROXIDE AS AN ALKALI SOURCE IN THE PEROXIDE BLEACHING OF SOFTWOOD TMP
CELLULOSE CHEMISTRY AND TECHNOLOGY SUBSTITUTION OF SODIUM HYDROXIDE WITH MAGNESIUM HYDROXIDE AS AN ALKALI SOURCE IN THE PEROXIDE BLEACHING OF SOFTWOOD TMP HUIREN HU and HONGJIE ZHANG * Tianjin Key Laboratory
More informationThe electrolysis of sodium chloride solution produces useful substances. covalent ionic non-metallic
1 The electrolysis of sodium chloride solution produces useful substances. (a) (i) Choose a word from the box to complete the sentence. covalent ionic non-metallic Electrolysis takes place when electricity
More informationIGCSE (9-1) Edexcel - Chemistry
IGCSE (9-1) Edexcel - Chemistry Principles of Chemistry Chemical Formulae, Equations and Calculations NOTES 1.25: Write word equations and balanced chemical equations (including state symbols): For reactions
More informationLACTIC ACID. The method is applicable to the determination of lactic acid and lactate salts (Note 2) in light or heavy steepwater.
LACTI.01-1 LACTIC ACID PRINCIPLE SCOPE Lactic acid in steepwater (Note 1) is oxidized to acetaldehyde following treatment with copper sulfate and calcium hydroxide to remove interfering substances. Acetaldehyde
More informationDuring photosynthesis, plants convert carbon dioxide and water into glucose (C 6 H 12 O 6 ) according to the reaction:
Example 4.1 Stoichiometry During photosynthesis, plants convert carbon dioxide and water into glucose (C 6 H 12 O 6 ) according to the reaction: Suppose that a particular plant consumes 37.8 g of CO 2
More informationC2.6 Quantitative Chemistry Foundation
C2.6 Quantitative Chemistry Foundation 1. Relative masses Use the periodic table to find the relative masses of the elements below. (Hint: The top number in each element box) Hydrogen Carbon Nitrogen Oxygen
More informationEffects of Metal Chlorides on the Solubility of Lignin in the Black Liquor of Prehydrolysis Kraft Pulping
Effects of Metal Chlorides on the Solubility of Lignin in the Black Liquor of Prehydrolysis Kraft Pulping Liang He, a Qiujuan Liu, a, * Youyue Song, a and Yulin Deng b The effects of CaCl2, MgCl2, FeCl3,
More informationC2.6 Quantitative Chemistry Foundation
C2.6 Quantitative Chemistry Foundation 1. Relative masses Use the periodic table to find the relative masses of the elements below. (Hint: The top number in each element box) Hydrogen Carbon Nitrogen Oxygen
More informationAlternative Alkalis in Peroxide Bleaching of Mechanical Pulp
Juha Tamper, Tomi Hietanen and Hannu Manner Laboratory of Paper Technology Lappeenranta University of Technology, Finland Alternative Alkalis in Peroxide Bleaching of Mechanical Pulp ABSTRACT Suitability
More informationIPC TECHNICAL PAPER SERIES NUMBER 227 THE EFFECT OF NITROGEN DIOXIDE PRETREATMENTS ON SOME PROPERTIES OF OXYGEN-BLEACHED KRAFT PULPS
THE INSTITUTE OF PAPER CHEMISTRY, APPLETON, WISCONSIN IPC TECHNICAL PAPER SERIES NUMBER 227 THE EFFECT OF NITROGEN DIOXIDE PRETREATMENTS ON SOME PROPERTIES OF OXYGEN-BLEACHED KRAFT PULPS N. S. THOMPSON
More informationUNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS General Certifi cate of Education Advanced Subsidiary Level and Advanced Level
UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS General Certifi cate of Education Advanced Subsidiary Level and Advanced Level *0926172746* CHEMISTRY 9701/33 Advanced Practical Skills 1 October/November
More informationEXPERIMENTS. Testing products of combustion: Reducing Copper(III) Oxide to Copper. Page 4
APPARATUS Page 2 APPARATUS Page 3 Reducing Copper(III) Oxide to Copper EXPERIMENTS Page 4 Testing products of combustion: EXPERIMENTS Showing that oxygen and water is needed for rusting iron Page 5 Showing
More informationUNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS General Certifi cate of Education Advanced Subsidiary Level and Advanced Level
*0974901356* UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS General Certifi cate of Education Advanced Subsidiary Level and Advanced Level CHEMISTRY 9701/31 Advanced Practical Skills 1 May/June 2013
More informationSanta Monica College Chemistry 11
Types of Reactions Objectives The objectives of this laboratory are as follows: To perform several types of simple chemical reactions, To become familiar with some common observable signs of chemical reactions,
More informationIn situ quantitation of ring-conjugated ethylenic lignin-units in spruce thermomechanical pulps by FT- Raman spectroscopy
In situ quantitation of ring-conjugated ethylenic lignin-units in spruce thermomechanical pulps by FT- Raman spectroscopy Umesh P. Agarwal and Sally A. Ralph USDA, FS, Forest Products Laboratory, Madison
More informationBasics of Bleaching Chemical Pulps Art J. Ragauskas Institute of Paper Science and Technology Georgia Institute of Technology
Basics of Bleaching Chemical Pulps Art J. Ragauskas Institute of Paper Science and Technology Georgia Institute of Technology Definition Chemical treatment to: Increase brightness Improve cleanliness Improve
More informationAngel International SchoolManipay
Grade OL Angel International SchoolManipay 2 nd Term Examination March, 2016 Chemistry Duration: 3 Hours 1. Which property is common to calcium, potassium and sodium? a) Their atoms all lose two electrons
More informationST. FRANCIS SECONDARY SCHOOL HALF YEARLY EXAMINATION SPECIMEN PAPER FORM 4 CHEMISTRY TIME: 2 HOURS. Name: Total Mark from 90:
ST. FRANCIS SECONDARY SCHOOL HALF YEARLY EXAMINATION SPECIMEN PAPER FORM 4 CHEMISTRY TIME: 2 HOURS Name: Total Mark from 90: A copy of the periodic table is provided during the exam. You are reminded of
More information(a) Complete Figure 9 by placing one tick in each row to show whether the salt is soluble or insoluble. salt soluble insoluble.
1 The method used to prepare a salt depends on its solubility in water. (a) Complete Figure 9 by placing one tick in each row to show whether the salt is soluble or insoluble. ammonium chloride salt soluble
More informationUNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS General Certificate of Education Advanced Subsidiary Level and Advanced Level
UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS General Certificate of Education Advanced Subsidiary Level and Advanced Level * 5803539249 * CHEMISTRY 9701/35 Paper 31 Advanced Practical Skills May/June
More informationAP Chemistry Unit 2 Test (Chapters 3 and 4)
AP Chemistry Unit 2 Test (Chapters 3 and 4) NAME: 1. A student is assigned the task of determining the mass percent of silver in an alloy of copper and silver by dissolving a sample of the alloy in excess
More informationST EDWARD S OXFORD. Lower Sixth Entrance Assessment. November Chemistry. 1 Hour. Candidates name:... St Edward's School 1
ST EDWARD S OXFORD Lower Sixth Entrance Assessment November 2013 Chemistry 1 Hour Candidates name:... St Edward's School 1 St Edward's School 2 1. Complete the table below. Element calcium Symbol Pb S
More informationGCE O' LEVEL PURE CHEMISTRY (5073/02) Suggested Answers for 2016 O Level Pure Chemistry Paper 2
Section A (50 M) Aa) trend The number of electron shell increases The number of valence electrons increases Proton number increases There is a change in character from metallic to non-metallic Only true
More informationUNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS General Certificate of Education Advanced Subsidiary Level and Advanced Level
UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS General Certificate of Education Advanced Subsidiary Level and Advanced Level * 8 2 6337145 4* CHEMISTRY 9701/33 Paper 31 Advanced Practical Skills May/June
More informationUnit 4: Chemical Changes (Higher Content)
Metals react with oxygen to produce metal oxides. E.g. Copper + Oxygen > Copper Oxide The reactions are oxidation reactions because the metals gain oxygen. Reactivity of Metals Metal Extraction Metals
More informationCambridge International Examinations Cambridge International Advanced Subsidiary and Advanced Level
Cambridge International Examinations Cambridge International Advanced Subsidiary and Advanced Level *7333871663* CHEMISTRY 9701/35 Paper 3 Advanced Practical Skills 1 May/June 2015 2 hours Candidates answer
More informationIdentify the reaction type, predict the products, and balance the equations. If it is a special decomposition or synthesis, identify which kind.
Identify the reaction type, predict the products, and balance the equations. If it is a special decomposition or synthesis, identify which kind. 1. calcium + oxygen 2. cupric carbonate 3. aluminum + hydrochloric
More informationUNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS General Certificate of Education Advanced Subsidiary Level and Advanced Level
UNVERSTY OF CAMBRDGE NTERNATONAL EXAMNATONS General Certificate of Education Advanced Subsidiary Level and Advanced Level *7779336909* CHEMSTRY 9701/35 Advanced Practical Skills May/June 2011 2 hours Candidates
More informationNITROGEN AND ITS COMPOUNDS Q30 (i) Explain how the following would affect the yield of ammonia. An increase in (i). Pressure.
NAME SCHOOL INDEX NUMBER DATE NITROGEN AND ITS COMPOUNDS 1. 1990 Q30 (i) Explain how the following would affect the yield of ammonia. An increase in (i). Pressure. (2 marks) marks)... (ii) Temperature
More informationCH3FP. (Jun15CH3FP01) General Certificate of Secondary Education Foundation Tier June Unit Chemistry C3 PMT. Time allowed 1 hour TOTAL
Centre Number Surname Candidate Number For Examiner s Use Other Names Candidate Signature Examiner s Initials Question Mark A Chemistry Unit Chemistry C3 Thursday 14 May 2015 For this paper you must have:
More informationS4 CHEMISTRY SUMMARY NOTES
S4 CHEMISTRY SUMMARY NOTES 1. The Mole One mole of a substance = GRAM FORMULA MASS e.g. H 2 SO 4 RAM from databook pg.7 2H 2 x 1 = 2 1S 1 x 32 = 32 4O 4 x 16 = 64 98g Mass = number of moles x Mass of 1
More informationCambridge International Examinations Cambridge International Advanced Subsidiary and Advanced Level
Cambridge International Examinations Cambridge International Advanced Subsidiary and Advanced Level *7278217255* CHEMISTRY 9701/34 Paper 3 Advanced Practical Skills 2 October/November 2014 2 hours Candidates
More informationPROCESS WATER RECOVERY: DISSOLVED AIR FLOTATION COMPARED TO HIGH SHEAR RATE SEPARATION
PROCESS WATER RECOVERY: DISSOLVED AIR FLOTATION COMPARED TO HIGH SHEAR RATE SEPARATION John H. Klungness, Research Chemical Engineer Freya Tan, Chemical Engineer Roland Gleisner, Engineering Technician
More informationMETHOD 9012 TOTAL AND AMENABLE CYANIDE (COLORIMETRIC, AUTOMATED UV)
METHOD 9012 TOTAL AND AMENABLE CYANIDE (COLORIMETRIC, AUTOMATED UV) 1.0 SCOPE AND APPLICATION 1.1 Method 9012 is used to determine the concentration of inorganic cyanide in an aqueous waste or leachate.
More informationYear 10 Science Chemistry Examination November 2011 Part A Multiple Choice
Year 10 Science Chemistry Examination November 2011 Part A Multiple Choice Answer these questions on the multiple choice answer sheet provided 2 Isotopes have been found as variations of atoms. Which of
More information10. Group 2. N Goalby chemrevise.org. Group 2 reactions. Reactions with oxygen. Reactions with water.
10. Group 2 Atomic radius Atomic radius increases down the Group. As one goes down the group, the atoms have more shells of electrons making the atom bigger. Melting points Down the group the melting points
More informationIn this activity, you will observe and predict products for some simple
Chemistry Not Chemistry My Type Not My Type Classifying Chemical Reactions In this activity, you will observe and predict products for some simple chemical reactions. You will classify the reactions as
More information3.2.6 Group II. Trends in Chemical properties. 164 minutes. 161 marks. Page 1 of 19
3.2.6 Group II Trends in Chemical properties 164 minutes 161 marks Page 1 of 19 Q1. (a) A small sample of barium metal was added to water in a flask. When the reaction had ceased, the contents of the flask
More informationChapter 4 Reactions in Aqueous Solutions. Copyright McGraw-Hill
Chapter 4 Reactions in Aqueous Solutions Copyright McGraw-Hill 2009 1 4.1 General Properties of Aqueous Solutions Solution - a homogeneous mixture Solute: the component that is dissolved Solvent: the component
More informationUNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS General Certifi cate of Education Advanced Subsidiary Level and Advanced Level
*0257891118* UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS General Certifi cate of Education Advanced Subsidiary Level and Advanced Level CHEMISTRY 9701/32 Advanced Practical Skills 2 May/June 2013
More informationELEMENTAL CHLORINE-FREE BLEACHING OF SODA RAPESEED PULP. Potůček F., Říhová M.
ELEMENTAL CHLORINE-FREE BLEACHING OF SODA RAPESEED PULP Potůček F., Říhová M. University of Pardubice, Faculty of Chemical Technology, Institute of Chemistry and Technology of Macromolecular Materials,
More information6V d.c. supply. State the form of energy used to carry out the electrolysis. (1)
1 (a) Water, acidified with a small amount of dilute sulfuric acid, can be decomposed by electrolysis using the apparatus shown. oxygen hydrogen acidified water + (i) 6V d.c. supply State the form of energy
More informationTypes of Chemical Reactions
Types of Chemical Reactions Objectives Perform and observe the results of a variety of chemical reactions. Become familiar with the observable signs of chemical reactions. Identify the products formed
More informationDescribe in full the colour change at the end-point of this titration. ... (1)
Q1. (a) A solution of barium hydroxide is often used for the titration of organic acids. A suitable indicator for the titration is thymol blue. Thymol blue is yellow in acid and blue in alkali. In a titration
More informationUNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS General Certifi cate of Education Advanced Subsidiary Level and Advanced Level
XtremePapers.com UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS General Certifi cate of Education Advanced Subsidiary Level and Advanced Level *8383886562* CHEMISTRY 9701/34 Advanced Practical Skills
More informationUNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS General Certifi cate of Education Advanced Subsidiary Level and Advanced Level
*0014911874* UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS General Certifi cate of Education Advanced Subsidiary Level and Advanced Level CHEMISTRY 9701/33 Advanced Practical Skills 1 May/June 2012
More informationPart 01 - Notes: Reactions & Classification
Objectives: Identify, define, and explain: combination reaction, synthesis reaction, decomposition reaction, single replacement reaction, double replacement reaction, combustion reaction, rapid oxidation,
More information1 (a) Describe a chemical test which shows the presence of water. Describe how water is treated before it is supplied to homes and industry.
1 (a) Describe a chemical test which shows the presence of water. test... colour change if water is present...... [3] (b) How could you show that a sample of water is pure?...[1] (c) Describe how water
More information4.4. Revision Checklist: Chemical Changes
4.4. Revision Checklist: Chemical Changes Reactivity of metals When metals react with other substances the metal atoms form positive ions. The reactivity of a metal is related to its tendency to form positive
More informationA-level CHEMISTRY (7405/1)
SPECIMEN MATERIAL A-level CHEMISTRY (7405/1) Paper 1: Inorganic and Physical Chemistry Specimen 2015 Session Time allowed: 2 hours Materials For this paper you must have: the Data Booklet, provided as
More information(DO NOT WRITE ON THIS TEST)
Final Prep Chap 8&9 (DO NOT WRITE ON THIS TEST) Multiple Choice Identify the choice that best completes the statement or answers the question. 1. After the correct formula for a reactant in an equation
More informationIdentification of Ions and Gases
Identification of Ions and Gases Question Paper 1 Level IGSE Subject hemistry (0620/0971) Exam oard ambridge International Examinations (IE) Topic cids, bases and salts Sub-Topic Identification of ions
More informationAngel International School - Manipay 1 st Term Examination November, 2015
Grade 11B Angel International School - Manipay 1 st Term Examination November, 2015 Chemistry - I Duration: 1.00 Hour Part 1 1) A liquid boils at a temperature of 100 o C. Which other property of the liquid
More informationName HONORS CHEMISTRY / / Oxide Reactions & Net Ionic Reactions
Name HONORS CHEMISTRY / / Oxide Reactions & Net Ionic Reactions The first type of reactions we will look at today are reactions between an oxide (a compound with oxygen as its anion) and water. There are
More informationChemical Reactions: An Introduction
Chemical Reactions: An Introduction Ions in Aqueous Solution Ionic Theory of Solutions Many ionic compounds dissociate into independent ions when dissolved in water H 2O NaCl(s) Na Cl These compounds that
More informationNomenclature for ionic compounds
Name: Nomenclature for ionic compounds Nomenclature is a system of naming. This worksheet presents a widely used system of nomenclature for ionic compounds. There are two types of metal cations with different
More informationEXPERIMENT 15 ESTIMATION OF MAGNESIUM AND. HP Y, etc. Structure
EXPERIMENT 15 1 ESTIMATION OF MAGNESIUM AND 1 CALCIUM IONS IN A MIXTURE BY COMPLEXOMETRY Structure 15.1 Introduction Objectives 15.2 'Principle 15.3 Requirements 15.4 Procedure 15.5 Obse~ations 15.6 Calculations
More informationWRITING AP EQUATIONS
WRITING AP EQUATIONS AP equation sets are found in the free-response section of the AP test. You get three equations to complete. The equations are of mixed types. The section is worth 15 points and is
More informationTHE UNITED REPUBLIC OF TANZANIA NATIONAL EXAMINATIONS COUNCIL CERTIFICATE OF SECONDARY EDUCATION EXAMINATION
THE UNITED REPUBLIC OF TANZANIA NATIONAL EXAMINATIONS COUNCIL CERTIFICATE OF SECONDARY EDUCATION EXAMINATION 032/1 CHEMISTRY 1 (For Both School and Private Candidates) Time: 3 Hours Thursday, 06 th November
More information4.4. Revision Checklist: Chemical Changes
4.4. Revision Checklist: Chemical Changes Reactivity of metals When metals react with other substances the metal atoms form positive ions. The reactivity of a metal is related to its tendency to form positive
More informationQuestion 1: Solution 1:
Book Name: Selina Concise Question 1: Comment, sulphuric acid is referred to as: (a) King of chemicals (b) Oil of vitriol Solution 1: (a) Sulphuric acid is called King of Chemicals because there is no
More informationTHE ST. MICHAEL SCHOOL THIRD FORM CHEMISTRY MANUAL 3 SYMBOLS AND FORMULAE, CHEMICAL BONDING AND CHEMICAL EQUATIONS
1 THE ST. MICHAEL SCHOOL THIRD FORM CHEMISTRY MANUAL 3 SYMBOLS AND FORMULAE, CHEMICAL BONDING AND CHEMICAL EQUATIONS COMPILED BY G.WALKER, L.WORRELL, T. HARDING REFERENCE BOOKS Anne Tindale Chemistry A
More informationST EDWARD S OXFORD 16+ ENTRANCE EXAMINATION. For entry in September Chemistry. Use of a calculator is permitted.
ST EDWARD S OXFORD 16+ ENTRANCE EXAMINATION For entry in September 2017 Chemistry Use of a calculator is permitted Time: 1 hour Candidate s Name: Total marks available: 60 St Edward's School 16+ Entrance
More informationCation Exchange Capacity, CEC
Cation Exchange Capacity, CEC The basic building blocks of clay minerals are: silicon atoms surrounded by four oxygen atoms (tetrahedra), and aluminium atoms surrounded by six hydroxide groups (dioctahedra),
More informationExperiment 8 - Double Displacement Reactions
Experiment 8 - Double Displacement Reactions A double displacement reaction involves two ionic compounds that are dissolved in water. In a double displacement reaction, it appears as though the ions are
More informationChemical Reactions and Equations
Chemical Reactions and Equations 5-1 5.1 What is a Chemical Reaction? A chemical reaction is a chemical change. A chemical reaction occurs when one or more substances is converted into one or more new
More informationKinetics Studies of Xylan and Acetyl- Group Hydrolysis
Dilute Acid Hydrolysis of Paper Birch: Kinetics Studies of Xylan and Acetyl- Group Hydrolysis Mark T. Maloney and Thomas W. Chapman Chemical Engineering Department, University of Wisconsin-Madison Andrew
More informationPhysical Changes and Chemical Reactions
Physical Changes and Chemical Reactions Gezahegn Chaka, Ph.D., and Sudha Madhugiri, Ph.D., Collin College Department of Chemistry Objectives Introduction To observe physical and chemical changes. To identify
More informationSome standard enthalpies of formation are given in the table below
Q1. Barium can be extracted from barium oxide (BaO) in a process using aluminium. A mixture of powdered barium oxide and powdered aluminium is heated strongly. The equation for this extraction process
More informationAdditional Science Chemistry
Additional Science Chemistry C2 Core Questions and Keywords and Definitions Question How did Mendeleev arrange the elements known at the time into a periodic table? How did Mendeleev use his table? Where
More informationburette filled with sulphuric acid conical flask 25.0 cm 3 of sodium hydroxide(aq) concentration 2.24 mol / dm 3
1 Crystals of sodium sulphate-10-water, Na 2 SO 4.10H 2 O, are prepared by titration. burette filled with sulphuric acid conical flask 25.0 cm 3 of sodium hydroxide(aq) concentration 2.24 mol / dm 3 (a)
More informationTotal, active and effective alkali
Accepted April 1985 White and green liquors Total, actie and effectie alkali Potentiometric titration 0 Introduction This SCAN-test Method has been deeloped for use in laboratories employing electrometric
More informationAdditional Science. Chemistry CH2FP. (Jun15CH2FP01) General Certificate of Secondary Education Foundation Tier June 2015.
Centre Number Surname Candidate Number For Examiner s Use Other Names Candidate Signature Examiner s Initials Question Mark Additional Science Unit Chemistry C2 Chemistry Unit Chemistry C2 Thursday 14
More informationWrite down everything that the word equation tells you about the reaction (Total 4 marks)
Q1. Here is a word equation for a chemical reaction. copper oxide + sulphuric acid copper sulphate + water Write down everything that the word equation tells you about the reaction.......... (Total 4 marks)
More informationUNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS General Certifi cate of Education Advanced Subsidiary Level and Advanced Level
XtremePapers.com UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS General Certifi cate of Education Advanced Subsidiary Level and Advanced Level *7736236717* CHEMISTRY 9701/36 Advanced Practical Skills
More informationAcid, Bases and Salts (IGCSE Chemistry Syllabus )
Acid, Bases and Salts (IGCSE Chemistry Syllabus 2016-2018) Acid o A compound when dissolved in water produces hydrogen ions (H + ) ; proton (H + ) donor o It turns blue damp litmus paper to red o ph 1
More informationName CHEMISTRY / / Oxide Reactions & Net Ionic Reactions
Name CHEMISTRY / / Oxide Reactions & Net Ionic Reactions The first type of reactions we will look at today are reactions between an oxide (a compound with oxygen as its anion) and water. There are two
More informationABB Analytical ORP/pH Chemical and mining
White paper ABB Analytical ORP/pH Chemical and mining ORP, like ph, a valuable measure of where a reaction stands This document outlines six real-world ORP applications, in non-technical style, that will
More informationCHAPTER 4 TYPES OF CHEMICAL REACTIONS & SOLUTION STOICHIOMETRY
Advanced Chemistry Name Hour Advanced Chemistry Approximate Timeline Students are expected to keep up with class work when absent. CHAPTER 4 TYPES OF CHEMICAL REACTIONS & SOLUTION STOICHIOMETRY Day Plans
More informationUNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS General Certificate of Education Advanced Subsidiary Level and Advanced Level *7382672438* CHEMISTRY 9701/33 Advanced Practical Skills October/November
More informationTYPES OF CHEMICAL REACTIONS
EXPERIMENT 11 (2 Weeks) Chemistry 110 Laboratory TYPES OF CHEMICAL REACTIONS PURPOSE: The purpose of this experiment is perform, balance and classify chemical reactions based on observations. Students
More informationFormic Acid Pulping of Bagasse
Bangladesh J. Sci. Ind. Res. 41(3-4), 245-250, 2006 Short Communication Formic Acid Pulping of Bagasse M. Sarwar Jahan Pulp and Paper Research Division, BCSIR Laboratories, Dhaka-1205, Bangladesh Abstract
More informationChapter 4 Compounds and Their Bonds. Octet Rule. Metals Form Positive Ions. Ionic and Covalent Bonds. Formation of a Sodium Ion, Na +
Chapter 4 Compounds and Their Bonds Octet Rule 4.1 Octet Rule and Ions An octet Is 8 valence electrons. Is associated with the stability of the noble gases. Helium (He) is stable with 2 valence electrons
More informationCambridge International Examinations Cambridge International Advanced Subsidiary and Advanced Level
Cambridge nternational Examinations Cambridge nternational Advanced Subsidiary and Advanced Level CHEMSTRY 9701/32 Paper 3 Advanced Practical Skills 2 May/June 2014 2 hours Candidates answer on the Question
More information1.11 Redox Equilibria
1.11 Redox Equilibria Electrochemical cells Electron flow A cell has two half cells. The two half cells have to be connected with a salt bridge. Simple half cells will consist of a metal (acts an electrode)
More informationProven Solutions to Minimize Inorganic Process Scaling in Pulp and Recovery
Proven Solutions to Minimize Inorganic Process Scaling in Pulp and Recovery Kraig R. Kent Global Pulp and Recovery Applications Manager November 25 th, 2013 Topics to Be Discussed 1. Increases in Inorganic
More information