از كاه گندم CMP بررسي توليد خمير كاغذ

Investigation on CMP pulping of wheat Straw

This research was carried out to investigate the chemical treatment conditions to produce CMP utilizing wheat straw. Fiber biometry as well as chemical characteristics of wheat straw were evaluated. Then chemical treatment involving two chemicals; sodium hydroxide (NaOH) and sodium sulfite (Na2SO3) buffered with sodium carbonate (Na2CO3) was done. Chemical charge was comprised 6, 8 and 10 percent (based on oven dry weight of straw) with treatment time being 20, 30 and 40 minutes. Treatment temperatures of 95 98°C at atmospheric pressure and L:W = 10:1 were selected. Regarding the results, sulfite treatments showed higher yield, screen reject and refining energy consumption as compared with sodium hydroxide treatment, because NaOH is more reactive than Na2SO3. NaOH dissolved more lignin and polysaccharides during treatment, decreased pulp yield and caused better and easier fiber separation leading toless screen reject produced. Considering pulp properties and treatment conditions, 6 treatments including 30 minute treatments, various chemicals and chemical charges were selected to handsheet. Selected pulps were refined up to 350 ± 25 m1.CSF freeness prior to making handsheets. Strength of papers produced from NaOH treatment was significantly higher than that of papers produced from sulfite treatment with chemical charges have showing direct effect on all paper strengths except burst strength.