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添加剂作用下铝酸钠溶液物化性质的变化对产品性能的影响 总被引:2,自引:0,他引:2
在铝酸钠溶液的晶种分解过程中,加入适当的添加剂--表面活性剂,可以强化铝酸钠溶液的晶种分解过程,提高产品氢氧化铝的强度、粒度和分解率.选用8种添加剂,100mg/L和200mg/L两种添加量做分解试验,对加入不同类型添加剂的铝酸钠溶液的表面张力、粘度、电导率进行了测试,考察了添加剂的加入量对铝酸钠溶液物理化学性质的影响.结果表明:添加剂C、E2、F可以提高铝酸钠溶液的分解率,并能增大产品氢氧化铝的粒度与强度;添加剂的加入使铝酸钠溶液的表面张力降低0.015~0.020N/m时,析出的氢氧化铝的粒度与强度较好;能使氢氧化铝粒度增大、强度提高的添加剂,均使铝酸钠溶液的粘度有所下降. 相似文献
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碱溶—碳分法生产氧化铝打破了拜耳法Na2O-Al2O3-H2O体系固有的相平衡,分解效率大幅度提高。研究了用NaOH溶液溶解铝土矿得到铝酸钠溶液,考察了铝酸钠溶液脱硅净化、碳酸氢钠分解及氢氧化铝焙烧对氧化铝产品质量的影响。结果表明,经两次石灰净化脱硅(净化温度98℃;一次净化时间1 h,石灰添加量15 g/L;二次净化时间1 h,石灰添加量10 g/L),二段分解(分解温度90℃,碳酸氢钠质量浓度90~100 g/L,缓慢持续加入,分解时间不大于16 h(其中一段8~10 h),第一段分解率控制在85%左右),适宜条件下,所得氢氧化铝质量达到一级品或接近一级品,在1200~1250℃煅烧后所得氧化铝产品质量可达二级品要求。 相似文献
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氧化铝的强度与氢氧化铝颗粒独特的显微形貌有着内在的联系,而氢氧化铝颗粒的显微形貌取决于铝酸钠溶液的分解工艺。氧化铝与氢氧化铝颗粒的显微形貌相似,通过跟踪监测流程中分解产物氢氧化铝颗粒的显微形貌来合理调整分解工艺,对得到强度较好的氧化铝产品有着重要的指导意义。 相似文献
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提出了一种新的采用溶析法分解铝酸钠溶液制备氢氧化铝的方法,成功制备了超细氢氧化铝。考察了分解温度、铝酸钠溶液浓度、分子比、溶析剂体积比等工艺参数对铝酸钠溶液分解率的影响,发现在常温下,Al2O3100~200g/L、分子比1.4~2.0的铝酸钠溶液与同体积的溶析剂反应,铝酸钠分解率大于90%。运用激光粒度分析仪、SEM、XRD、TG-DTA对粒子的性能进行了表征,结果表明产品为拜耳石片状晶体,产品晶型完整、粒度分布均匀、纯度高。 相似文献
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表面活性剂加强氧化铝种分分解粒度分布研究 总被引:13,自引:2,他引:11
铝酸钠溶液中加入有机表面活性剂可以强化分解过程 ,增加产品氢氧化铝的粒度。其中加入硬脂酸是吸附在颗粒表面 ,使种子表面疏水 ;而石蜡油的加入可强化疏水性质 ,并在 2个或多个固体颗粒粘结时起着“桥梁”作用。对产品氢氧化铝用热重和红外光谱分析 ,得出产品氢氧化铝在低于 10 0 0℃焙烧后 ,有机物添加剂可有效分解 ,不会带入后面的铝电解工序中。 相似文献
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利用氢氧化钠的强碱性和消融性,将赤泥试样经氢氧化钠在马弗炉中加热熔融。熔融物先在温水中洗出,加入30 mL盐酸溶解,然后加入铝片还原,采用碳酸氢钠溶液保护,最后以硫氰酸铵溶液作为指示剂,采用硫酸铁铵滴定法测定赤泥中的二氧化钛含量。研究了样品用量、粒度、氢氧化钠用量、焙烧条件、溶样条件和保护溶液对测定的影响,结果表明:最佳实验条件是氢氧化钠用量为6 g、焙烧温度为650 ℃、焙烧时间为20 min、还原剂为2.2 g铝片、保护溶液为饱和碳酸氢钠溶液、滴定前放置时间不超过15 min。采用实验方法对实际赤泥样品中二氧化钛进行测定,测定值与电感耦合等离子体原子发射光谱法测得结果相近,相对标准偏差(n=5)均小于0.2%。 相似文献
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A method for the dissolution of uric acid urolithiasis by irrigation with sodium bicarbonate solution through a ureteral catheter is described. 相似文献
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研究了磷酸盐杂质对铝酸钠溶液晶种分解的影响,并探讨了其影响机理.结果表明,在浓度小于5g/L时,磷酸盐能提高铝酸钠溶液的分解率,使晶种分解产品的粒度增大.磷酸盐杂质的存在不会显著影响铝酸钠溶液中氢氧化铝颗粒表面的Zeta电位值,但是会使铝酸钠溶液表面张力增大. 相似文献
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The antacid properties of seven antacids listed in the hospital formulary of a medical center were evaluated with in vitro tests. These included not only the preliminary antacid test and acid-neutralizing capacity test as described in the United States Pharmacopeia (USP XXIII), but also a buffering pH profile test. The preliminary antacid test measured the final pH of a 10-mL solution of 0.5 N HCl 10 minutes after addition of the minimum recommended dose of an antacid, while the neutralizing capacity test measured the amount (mEq) of HCl neutralized by the minimum recommended dose in 15 minutes. The buffering pH profile recorded the pH time course of dynamic simulated gastric fluid neutralization by a dose of an antacid. In the preliminary antacid test, magnesium oxide showed the highest pH (9.52 +/- 0.14, mean +/- standard deviation, n = 3); aluminum phosphate gel yielded a final pH of 2.51 +/- 0.01, thus failing to meet the criteria of an antacid (pH > 3.5). In the acid-neutralizing capacity test, hydrotalcite had the highest neutralizing capacity (28.26 +/- 0.3 mEq), while sodium bicarbonate had the lowest (7.40 +/- 0.12 mEq). In the buffering pH profile test, aluminum-magnesium hydroxide suspensions and hydrotalcite tablets maintained a steady optimum pH (3-5) for around 1.5 hours. One tablet of calcium carbonate, sodium bicarbonate or magnesium oxide could not raise the gastric pH to above 3, but two tablets increased the pH excessively (5.3 to 8.6). The higher dose (two tablets) of aluminum hydroxide hexitol complex could not raise the pH to the optimal level. These findings demonstrate that there is disparity in the antacid effectiveness estimated by the neutralizing capacity test and the buffering pH profile test and suggest that the efficacy of an antacid cannot be accurately predicted from its acid-neutralizing capacity. The dose of antacids greatly influences the neutralizing pH profiles. Aluminum-magnesium compounds appear to provide steadier buffering than carbonate compounds or magnesium oxide. 相似文献
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OBJECTIVES: Cardiac depression is the main adverse effect of severe tricyclic antidepressant poisoning. The aim of this study was to investigate whether treatment with epinephrine or norepinephrine increases survival as compared with standard treatment with sodium bicarbonate in experimental amitriptyline poisoning. DESIGN: Nonrandomized, controlled intervention trial. SETTING: University laboratory. SUBJECTS: Male, anesthetized, paralyzed, and mechanically ventilated Sprague-Dawley rats (n = 91). INTERVENTIONS: Rats subjected to a 60-min infusion of amitriptyline (2 mg/kg/min) were treated with a continuous infusion of either epinephrine, norepinephrine, sodium bicarbonate, epinephrine plus sodium bicarbonate, norepinephrine plus sodium bicarbonate, or placebo. MEASUREMENTS AND MAIN RESULTS: Inotropic drug treatment was associated with an increased survival rate as compared with treatment with sodium bicarbonate and treatment with placebo. Epinephrine treatment was superior to norepinephrine. Additional treatment with sodium bicarbonate increased survival rate for each inotropic drug. Sodium bicarbonate and inotropic drug treatment independently increased the survival rate (p < .001 for both effects). No interaction between these two treatment effects was observed. CONCLUSIONS: Both epinephrine and norepinephrine increased the survival rate in tricyclic antidepressant poisoning in rats. Sodium bicarbonate increased the survival rate independent of inotropic drug treatment. Furthermore, epinephrine was superior to norepinephrine when used both with and without sodium bicarbonate, and the most effective treatment was epinephrine plus sodium bicarbonate. 相似文献
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含毒砂矿石中锡的测定 总被引:1,自引:0,他引:1
本文选择硼砂、硼酸和锌粉混合熔剂,熔融试样,用铁粉还原,然后用铝片还原,再使用装有饱和碳酸氢钠的盖氏漏斗保护,用碘酸钾标准溶液滴定,方法操作简便,易掌握,分析成本低,可以分析0.3%以上的锡。 相似文献
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利用钢铁和铝的熔点不同的特性,将钢芯铝块置于设定的温度下,使铝熔化与钢芯铁棒分离、冷却,分别称量钢芯铁棒和铝的重量计算铁和铝的比例。铝的纯度的测定,在熔化冷却的铝块上钻取试样,以氢氧化钠溶解酸化定容,取部分试液用氟化铵取代-EDTA间接滴定法测定铝的含量。 相似文献