Research On The Technology Of Wheat Straw Chemical Clean Pulping And Co-Production Of Ecological Organic Fertilizer With Pulping Derived Black Liquor

The grass straw resources in China is very rich,unfortunately,industrialized technology of utilizing straw resources has been a problem;the ecological organic fertilizer with multifunction of supplying soil nutrients and improving sandy land has been lacking;managing the desertification in China has been difficult.In this paper,aiming at solving these problems mentioned above,the experiments of researching on the efficient use of straw resources,comprehensive utilization of wheat straw papermaking black liquor and ecological fertilizer fixing sand were conducted in this paper.Jinnan paper mill of Hongchang agricultural and industrial co.,LTD and desertification key laboratory of the Chinese Academy of Sciences are cooperation units of this research.Based on literature research and on-the-spot investigation,circular economy clean production technology and technical solutions were designed.Wheat straw and chemical materials of clean-pulping process were used as research subject in this paper.Traditional chemical pulping technology was modified and improved in this research.Environmental-friendly cooking reagent of KOH?K2SO3?Mg(OH)2?MgO?NH4OH(NH3·H2O)?(NH4)2SO3?AQ was employed to replace soda in pulping process,The main results of this work could be summarized as follows.1 MgNH4K(SO3)2 clean pulping technology and co-production of organic fertilizer with black liquor experiments.In contrast to traditional cooking reagent NaOH+Na2SO3,3 materials were tested in 3 levels,each experiment was duplicated 3 times.The combination of(NH4)2SO3 + K2SO3 + Mg SO3 was determined as the cooking reagent,based on cooking result and economic expense.The dosage of MgO,K20,NH3,AQ and H2SO3 are 6%,10%,15%,0.05%and 30%respectively.The pH value of cooking reagent is between 8.3 to 9.3,ratio of liquid to solid was set at 4:1,idling time is 20 min,heating time is 60min,maximum temperature is 150?,holding time is 60min,spraying time is 10 min.The results show that the rate of delignification of wheat straw is 86.5%,paper pulp yield is 49.7%,permanganate number is 13.6%.The industrialization of desertification control using sand-fixing and soil-conserving organic fertilizer made from the harmless black liquor were realized.2.magnesium,potassium and ammonium complex cooking reagent clean-pulping technology and co-production of ecological mulching film with black liquor experiments.In contrast to traditional cooking reagent NaOH+Na2S03,8 levels of cooking reagent was prepared with Mg(OH)2,NH40H and KOH,each experiment was duplicated 3 times,based on cooking result and economic expense.The dosage of MgO,K20,NH3,AQ and H2S03 are 6%,6%,20%,0.05%and 30%respectively.The pH value of cooking reagent is between 9.6 to 10.6,ratio of liquid to solid was set at 5:1,idling time is 20 min,heating time is 60min,maximum temperature is 150?,holding time is 60min.The results show that the rate of delignification of wheat straw is 86.3%,paper pulp yield is 48.35%,permanganate number is 12%.The harmless black liquor was utilized to produce mulching film successfully.The produced double-sided writing paper passed test according to the national standard of GB/T12654-1990.Black liquor produced in clean pulping process and co-generated sand-fixing and soil-conserving organic fertilizer were analyzed and tested by state key laboratory of desertification of china academy of sciences and Soil and Fertilizer Institute of Shanxi Academy of Agricultural Sciences.The test results are as follows,content of inorganic nutrients is 7.2%--13.92%,content of organic matters is 36.66%--42.2%,content of humic acid is 27.72%,consolidation strength is 160kPa-250kPa.3.Sand-fixing laboratory experiment and field test of soil-conserving environment-friendly black liquor from papermaking industry.The experiment of anti-wind erosion properties,consolidation strength,construction technology,operation method,plant growth field test of sand fixation and the technology of planting grass by spraying seeds were done in wind tunnel laboratory and desert observation station of Chinese academy of sciences in a specific order.The experimental results demonstrate that the product is a novel sand-fixing material and suitable for field application of anti-desertification.The organic fertilizer was used as functional material,perennial wild salt tolerance herbage species were employed as basic materials.The fertilizer and herbage seed were sprayed at the same time.Organic fertilizer could not only play the role of sand fixation,but also supply nutrients for the plant growth.In this way,vegetation was formed to realize the long-run goal of soil and water conservation.Over 2358 hm2 of technique demonstration field was carried out in Zhangye forest farm of Gansu province,Gonghe county of Qinghai province and Yellow river beach in recent years.application result reveal that desertification control result is excellent and economical.The cost of sand fixation is only 0.43 RMB per m,which is 0.55 and 4.5 RMB lower than the similar international and domestic product,respectively.4.Principle and advantage of this product.First,the bonding property of pentosan and lignin in the ecological organic fertilizer could facilitate the formation of 1-2mm organic fertilizer membrane on the surface of sand as soon as the fertilizer was sprayed.Rain water could easily penetrate the pore structure of the membrane,however,the evaporation of moisture in the sand could be inhibited.Second,the nutrients in the fertilizer membrane could be brought by rain water and seeped into sand and soil layer to fertilize plants.Third,The Microbial degradation of the ecological organic membrane could be achieved thoroughly without causing white pollution problem.Forth,Watering,fertilizing and filming could be accomplished at one time.Fifth,Ecological organic membrane could play the role of sand fixation at the early stage,which could also supply nutrients and water for herbage during their growth period to accelerate the formation of herbage self-developing system.Sixth,notable functions of nitrogen fixation of legumes could improve the absorption of organic nutrients,nitrogen and potassium in the ecological organic membrane.5.Application prospect of results of this research.The application of the research result could transform the traditional single production pattern of paper to the novel co-production pattern of paper and fertilizer.Black liquor was recycled and converted from harmful waster into useful and profitable product,furthermore,desertification control could also be solved at the same time.The sustainable development of circular economy of wheat straw——pulping——ecological fertilizer——sand fixing——pasture production——straw could be realized possibly.This technology is suitable for application in small and medium size paper mills.The co-generated sand-fixing ecological organic fertilizer could be applied to the desertification control and prevention,production of pasture,fertilization of the soil and vegetation recovery of reclamation region in west China.