| Barite is an advantageous mineral resource in China,which is widely used in petroleum,chemical,filler,medicine and other fields.Guizhou Province has the largest barite mineral resources reserves in China.This thesis has created both radiation-proof ceramic plate and resin plate using barite from different origins in Tianzhu County and Majiang County,Guizhou Province,respectively,which is a new solution for the resource utilization of barite.Barium slag is a hazardous solid waste produced in the process of barite production of barium salt,listed in the"National Hazardous Waste List"HW47,the thesis used the newly barium slag piled up in the first production line of a barium salt company in Guizhou Province and the old barium slag piled up in the second production line for harmless treatment and mixed with barite to produce radiation-proof resin plate,which is a new way of harmless treatment of barium slag and efficient utilization of resources.Using barite from Tianzhu County and Majiang County,Guizhou Province,respectively,as the main raw materials,a certain amount of sodium silicate,alumina,zinc oxide and aluminum dihydrogen phosphate as sintering aids,the new high-density radiation-proof barite ceramic plate were prepared by cold pressing and molding under certain conditions,followed by high-temperature sintering.It is shown that the surface of the obtained barite ceramic plate is smooth and flat,and the barite particles and sintering additives are sintered at high temperature to form a high-density structure,with an apparent density of 1470 kg/m~3 and compressive resistance up to 41.5 MPa,at a pressure of 25 MPa cold pressing molding,sintering temperature of 1000°C and holding time of 2 h,and annealing to room temperature.The apparent density of ceramic plate prepared from barite in Majiang County is 1467kg/m~3 and the compressive performance can reach 37.9MPa,both of which meet the standard of GB/T30018-2013"Sintered decorative plate".The measurement results of X-ray protection attenuation performance of the new barite ceramic plate show that the lead equivalent value of 10mm ceramic plate prepared by Tianzhu County barite is0.96mm Pb,and the lead equivalent value of 10mm ceramic plate prepared by Majiang County barite is 0.98mm Pb,both of which have good radiation resistance performance.In addition,barite was used as the main filler,and a certain amount of silicone resin and curing agent etc.were used as binder,and the new type of radiation-proof barite resin plate was made under vacuum reaction conditions after pressurization.The study showed that with 90%barite content,40MPa molding pressure and 7d curing time,the surface of the obtained barite resin plate was smooth and flat without bubbles,and the water absorption rate of the resin plate prepared by barite in Tianzhu County was 0.0156%,and the compressive strength was up to 85.1MPa,and the water absorption rate of the resin plate prepared by barite in Majiang County was 0.0143%,and the compressive strength was up to 90.3MPa.The measurement results of X-ray protection attenuation performance of the new barite resin plate show that the lead equivalent value of the resin plate with thickness of 10mm prepared by Tianzhu County barite is 1.00mm Pb,and the lead equivalent value of the resin plate with thickness of 10mm prepared by Majiang County barite is 1.12mm Pb,both of which have good radiation resistance performance.Newly barium slag and old barium slag piled up in a barium salt company in Guizhou were used as the main samples,and Na2SO4 was used as an additive for harmless treatment.The study showed that at the reaction temperature of 80℃,reaction time of 2h and Na2SO4 excess coefficient of 1.25,the concentration of soluble barium ions of the modified newly barium slag was 82.14mg/L and the concentration of soluble barium ions of the modified old barium slag was 72.73mg/L,both of which were in line with the GB5085.3-2007"Hazardous waste identification standard leaching toxicity identification"for barium ions Toxicity identification standard limit value of 100mg/L,the recovery rate of soluble barium ions of modified newly barium slag can reach 96.87%,the content of barium sulfate increased by84.47%,the recovery rate of soluble barium ions of modified old barium slag reached97.22%,the content of barium sulfate increased by 75.73%.Then the modified barium slag doped with barite was used to prepare radiation-proof resin plate.The study showed that the hardness of the plate could reach 82HD at45%of barite doping,and the barium sulfate content was increased by 45.01%compared to that of the resin plate,and the surface of the resin plate obtained was flat without bubbles,and the water absorption rate of the resin plate prepared by modified newly barium slag doped with barite was 0.306%,and the compressive strength was up to 61.3MPa,and the water absorption rate of the plate prepared by modified old barium slag doped with barite was 0.295%,compressive strength up to 58.2MPa.The X-ray protection attenuation performance of the new modified barium slag doped barite resin plate is measured,and the lead equivalent value of the modified newly barium slag doped barite resin plate with thickness of 10mm is 0.91mm Pb,and the lead equivalent value of the modified old barium slag doped barite resin plate with thickness of 10mm is 0.84mm Pb,both of which have good radiation resistance performance. |
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