Studies On Technics Of Medium Density Fiberboard By Paper Mill Sludge

The project was introduced,which belonged to 948 Program,"Utilization of Paper mill sludge for manufacturing fiberboard" of China.The article was composed by three parts:The character of paper mill sludge;the technics of board by paper mill sludge solely and the composed board by paper sludge and wood fiber.The basic characteristic of sludge was researched for the first.The feasibility of producing fiberboard by only paper mill sludge was probed into.And the density,the content of resin and the hot pressing properties of the effect for bending modulus(MOE), strength(MOR),internal bond strength(IBS),and thickness swelling(TS) of medium density fiberboard(MDF) was analyzed according to GB/T18580-2001.The manufacture of composites of wood mill sludge and wood fibers was also investigated at last.Fourier transform infrared spectrophotometer(FTIR) showed:Si,in the surface layers of sludge,was detected in kinds of forms silicon dioxide.After glue application,compared to adhesive joint of PF and sludge,the layer of resin is thicker than urea formaldehyde(UF) and sludge.And much active was detected by phenol-formaldehyde(PF).Thermogravimetry-Differencial Scanning Calorimentry(DSC) showed that there were no phenomena of absorbing and putting hot when the paper mill sludge was heated.And there were certain obvious phenomena of absorbing and putting hot when UF and paper mill sludge were heated.Compared to UF and sludge the hot-reaction was clearer by paper mill sludge and PF.In this study,manufacture board by paper mill sludge solely also indicated that the density was the most important effect to the bending properties of sludge board. And for the temperature and time of hot press which was not the most important.For needs of the Program,the better appropriate technical conditions were as follows: thickness-10mm,density-0.8g/cm~3,hot press temperature-160℃,hot press time-30sec/mm,the resin content for the paper mill sludge-13%.Technics of paper mill sludge and wood fiber composite boards also indicated that wood fiber to paper mill sludge ratio has great effect on the properties of board. And the effect of mixing methods on the mechanical properties was not obvious.With the adding of wood fiber,the physical and mechanical of board increased evidently.The optimal parameter composite of board as follows:the density-0.8g/cm~3,the PF resin content for the paper mill sludge-13%,for wood fiber-10%,hot press temperature-160℃,hot press time-30sec/mm.And the spreading raw materials were separated.With 30%Non-classification sludge-grain,the experiment results of MOR, MOE,IB,after boiling IB,TS are 27.08MPa,2.82GPa,1.035MPa,0.225MPa, 6.46%.