IUFRO Division 5 Conference P & P C: Mechanical Non-wood pulping

1. PARIZAD SHEIKHI IUFRO Division 5 Conference P &P C: Mechanical Non-wood pulping

2. PARIZAD SHEIKHI*, AHMAD JAHAN LATIBARI Application of two chelating agents on bagasse APMP pulping Islamic Azad University dezful branch, Dezful, Iran

3. Introduction

4. The chemical and mechanical pulping processes: • Conventional chemical pulping of non – wood posses some difficulties such as air and water pollution as well as requirement for installation of expensive chemical recovery system. • Consequently mechanical pulping processes have been investigated as environmental friendly pulping processes for pulp production. • One value alternative in these processes will be APMP which produces bleached pulp by utilizing both delignification and bleaching chemicals in treatment stage, without requiring separate bleaching stage.

5. Wood fiber and Non – wood fiber: The paper industry in Iran is in a unique situation. A limited area of Iran is covered with forests which must provide wood for large number of small and medium size wood processing plants. Even though Iran has established two large pulp and paper mills in Northern Iran, but both mills are facing with shortage of wood. Therefore, Iran must depend on non-wood fiber supplies for development of paper industry to fulfill its ever increasing demand of its growing and enthusiastic population. Non-wood fibers especially by-products from agricultural activities such as wheat, rye and rice straw as well as bagasse shows good potential. Countries such as India and China have based their industrial development on non-wood fiber supplies.

6. Bagasse: • Bagasse shows the most potential in this case. It is annually and continuously available in large quantities adjacent to sugar mills. The utilization of bagasse in paper production preserves our environment and causes the production of value added commodities. In this case, writing and printing grade pulp from bagasse has been produced by soda pulping process. Even though soda pulping of bagasse has been considered as the only alternative, but during last decade bagasse high yield pulping has been also considered as other alternative especially for production of newsprint in fiber deficient countries who are importing large quantities of newsprint paper.

8. Presently Iran has established 9 sugar cane agro-industrial project Which produce 3000000 Ton/year raw bagasse. This volume of bagasse can be utilized in cellulose industries mainly pulping and papermaking.

9. Literature: Eric C. X., 2001:APMP pulps from nonwood fiber, part 2: Jute Salehi et al, 2001: Application of APMP pulping on bagasse George X. et al, 2000: Alkaline peroxide mechanical pulping of wheat straw Ghosh Ni. et al, 2000: Metal ion complexes and their relationship to pulp brightness

10. The objectives of study: Hydrogen peroxide has been used in APMP process: because treatment with alkali darkens the lignocellulosic material. When the alkaline softener is combined with an organic or inorganic peroxide, this darkening of the material is counteracted while greatly improving, at the same time, the potential of the fiber material for increased brightness during the process. The presence of iron, copper and manganese catalyze the composition of H2O2 during chemical treatment. Therefore application of peroxide stabilizing pretreatment is required. Our main objective was to inactivate metal ions by addition of chelating agents i.e. DTPA and EDTA in bagasse preparation to improve the optical properties.

11. Method: Pretreatment: Two pretreatments were investigated. Variables in each pretreatment were as following: 1-DTPA at 0.25,0.5, 0.75% w/w BD bagasse 2-EDTA at 0.25, 0.5, 0.75% BD bagasse - time: 20 and 40 minutes - temperature:70 C

12. Chemical treatment for pulping was kept constant for all pretreatments as following: NaOH charge: 4% w/w of BD bagasse H2O2 charge: 3% w/w of BD Bagasse time: 30 minutes temperature: 80°C

13. Determination of Optical properties: • Optical were measured in accordance with TAPPI TEST Method T452 om – 98 • Determination of copper, iron and manganese: • Metal ions were measured in accordance with T266 om – 94

14. Results

15. Table 1:Optical properties of APMP pulp produced from different pretreatment

18. We have experiment with 3 levels of chelating agent. It is usually expected that adding more chelating agent will improve brightness because the presence some metals in the pulp will decompose H2O2 in brightening of pulp. Therefore if more chelating agent is added then the complexing potential will be more and the presence of metal will be reduced. However we were lucky that the addition of 0.25 percent was sufficient and application of more chelating agent was not any further help. Why it happened: Bagasse contains Silica and Silica itself with help H2O2 stabilization, therefore the small amount of 0.25 percent is sufficient. SO: Anybody who wants to produce bleached pulp from bagasse should not worry about requirement of application of too much chelating agent.

19. Table2: Transition metal content of untreated bagasse and bagasse treated with 0.5% DTPA or EDTA at 20 Min.

20. Table3: Transition metal content of untreated bagasse and bagasse treated with 0.5% DTPA or EDTA at 40 min.

21. Conclusion: Pretreatment reduced the transition metal content of bagasse which helped production of brighter APMP pulps. Pretreatment with 0.25, 0.5, 0.75% DTPA or ETPA increased the brightness of APMP pulp by almost 3 to 4 % and reduced the yellowness about 2%. The results indicate that the amount of chelating agent will not significantly influence the optical properties and ion metals of pulp.

22. Thank you for your kind attention