| The mixed wastepaper of ONP/OMG is a common kind of wastepaper material. Becausethe source of ONP/OMG is complicated, and the change of fiber and ink composition ofONP/OMG is great in different groups of material, the deinking of ONP/OMG is moredifficult. At present, most of the deinking process of ONP/OMG is alkali deinking technologyin industry. But with the increasing of deinking cost and increasingly showing of drawback ofalkali deinking technology, neutral deinking technology is gradually used in deinking processof ONP/OMG in industry.In this thesis, neutral deinking technology of ONP/OMG was studied.Neutral deinking performance of different surfactants and their mixtures was studied inthe first part of this study. In flotation-washing deinking process,24 kinds of differentsurfactants and their mixtures were used in neutral deinking of ONP/OMG, As a result, ninekinds of THJ series neutral deinking agent were excellent in ONP/OMG deinking. When thedosage of THJ series deinking agent was 1.0%, the whiteness of ONP/OMG neutral DIP couldbe enhanced more than 10.0%ISO.The technological conditions of ONP/OMG neutral deinking was studied in the secondpart of this study. Agent THJ-5 was used to discuss the influence of change of deinkingtechnology conditions(repulping temperature, repulping time, repulping consistency,act) onONP/OMG neutral deinking, and a proper technological condition was gained.It was showedthat deinking agent dosage was 0.75%, repulping temperature was 70℃, repulping consistencywas 5.0%, repulping time was 20min, maturation time was 15min, flotation temperature was50℃, flotation concentration was 1.0%, flotation time was 8min, and wash times was 2. Underthis condition, the whiteness of ONP/OMG neutral DIP could be enhanced more than15.5%ISO, while the ERIC concentration could be decreased to 186mg/kg.In the Final part of this study, the neutral deinking technology of ONP/OMG(quality ofDIP, load of pollution, deinking cost, act) was evaluated roundly and compared with alkalideinking technology. The results showed that the qualities of neutral DIP and alkali DIP weresimilar, but neutral deinking technology had an obvious advantage in the fields of load ofpollution and deinking cost.The studying result proved that the neutral deinking technology of ONP/OMG wascompletely feasible. Neutral deinking agent which is good at deinking ONP/OMG can beobtained by the mixture of existing surfactants. On the basis of not changing deinkingprocess,the efficiency of neutral deinking agent can be maximized by adjusting technologicalparameters of deinking process. By appropriate neutral deinking agent and on appropriate deinking technological conditions, the effects of neutral deinking and alkali deinking weresimilar, but neutral deinking technology had a obvious advantage in the field of load ofpollution and deinking cost. |
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