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

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.     

磷酸钠对铝酸钠溶液晶种分解的影响

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.     

分解工艺制度对碳分产品粒度的影响

采用间断碳分的方法，研究了不同搅拌和晶种添加情况对铝酸钠溶液碳酸化分解产品粒度的影响规律。结果表明：采用先快后慢搅拌制度有利于提高产品粒度：随着晶种系数的增大产品平均粒径先增大后减小，晶种系数-0．32达到最大；产品平均粒径随着晶种粒度的增粗而增大，添加粗晶种时，20—45μm颗粒间仍可发生明显附聚。通过控制合适分解工艺，可获得粒度较粗、分布均匀的砂状Al（OH）3产品。     

呋喃糖类添加剂对铝酸钠溶液种分过程的影响

选用核糖作为铝酸钠溶液种分过程的添加剂,在αk=1.40、温度75℃、搅拌速度140 r/min、晶种添加量为80 g/L条件下,研究不同添加量和不同苛碱浓度下铝酸钠溶液种分分解率及产品粒度的变化,结果表明:当添加量为150 mg/L、苛碱浓度为160 g/L时,核糖对种分过程的抑制作用最大。随着核糖添加量的增大,产品氢氧化铝粒度减小,但是核糖的添加并不能完全抑制氢氧化铝的附聚。核糖的加入改变了种分过程,且随着苛碱浓度的增大,种分过程出现成核现象,成核现象持续的时间也越长。     

铝酸钠溶液种分过程降温制度的研究

研究了铝酸钠溶液晶种分解过程中的相对过饱和度、分解率、产品粒度分布和反应速率常数在不同温度下的变化情况。结果表明,在50~75℃,铝酸钠溶液的相对过饱和度随温度的升高而逐渐减小,产品的平均粒度和反应速率常数随温度升高而增大,铝酸钠溶液种分分解率在65℃时达到最大。在降温制度下,铝酸钠溶液种分的分解率为28.86%,仅略低于65℃时的分解率,而产品粒度大于65℃时的产品粒度,降温制度下的铝酸钠溶液种分既能保证分解率又能提高产品氢氧化铝的粒度。     

种分蒸发器防垢节能技术的研究与应用

种分母液的蒸发过程,一方面是为了维持氧化铝生产系统水平衡的需要,另一方面也可以达到排盐、除杂的目的。由于铝酸钠溶液中含有一定浓度的碳酸钠、硫酸钠、二氧化硅等杂质,在蒸发过程中,随着铝酸钠溶液中各组份浓度的不断增大,碳酸钠等物质的平衡     

晶种对拜耳法铝酸钠溶液分解的影响

本文讨论了种分晶种、碳分晶种和球磨碳分晶种对拜耳法铝酸钠溶液分解的分解速度、分解率及产品粒度的影响。试验发现加入碳分晶种分解的初期分解速度比种分晶种高，但分解３６ｈ后的分解率要比加入种分晶种分解的分解率低；而加入球磨碳分晶种分解速率不如加入种分筛分晶种分解速率高，同时还讨论了加入不同晶种对分解影响的原因。     

溶析法分解铝酸钠溶液制备氢氧化铝

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。     

硫酸钠对铝酸钠溶液种分过程的影响

针对我国氧化铝的生产现状,研究了有害物质硫酸钠对铝酸钠溶液分解过程的影响规律.结果表明,分解首温一定的条件下,分解末温升高可消除硫酸钠对分解率的影响,但不利于产物粒度的提高;分解温度制度为68～52℃的条件下,硫酸钠质量浓度为9g/L时分解产物氢氧化铝的强度最好,相比空白其磨损系数降低4.4%.     

铝酸钠溶液晶种分解过程的研究进展

铝酸钠溶液种分过程的复杂性在于铝酸根阴离子结构随浓度变化的复杂性。系统总结了近年来铝酸钠溶液晶种分解过程分解机理的研究进展,并详细地介绍了强化铝酸钠溶液晶种分解的不同方法。超声波、磁场、活化晶种、添加剂等方法对强化铝酸钠溶液晶种分解具有不同的作用,各有特点,可相互协同,极大提高铝酸钠溶液的分解速度和分解深度,从而得到优质的氧化铝产品。     

Sodium

Disorders of serum sodium are both the most common and probably most the poorly understood electrolyte disorders in clinical medicine. In the past few years increased knowledge about the non-osmotic release of vasopressin and the cloning of vasopressin receptors and of vasopressin-regulated water channels (AQP2) has enhanced our understanding of these disorders. Also controversies surrounding the treatment of hyponatraemic patients have led to well-accepted therapeutic guidelines.     

亚硫酸钠对铝酸钠种分母液排盐的影响

对亚硫酸钠对种分母液蒸发排盐的影响进行研究。结果表明,铝酸钠溶液中碳酸钠、硫盐和氢氧化铝的析出率随亚硫酸钠含量的增加而增加,排盐渣中主要物相为NaAlO2·1.25H2O、Na2CO3、Na2SO3、Na2SO4等,种分母液在蒸发过程中约有7%¹1%的亚硫酸钠被氧化为硫酸钠。碳酸钠、硫酸钠和亚硫酸钠交互作用可以影响蒸发排盐的效果。     

硫代硫酸盐和多硫化物混合浸金体系制备研究

对用硫粉和氢氧化钠制备硫代硫酸钠和多硫化钠混合浸金体系的反应条件进行了实验,该制备反应的最佳条件是:搅拌速度200 r/min、反应时间30~40 min、温度353 K、NaOH与S摩尔比1.5、氧气压力1.1 MPa。该条件下得到的混合溶液中,S2O32-浓度较高。     

用黑铜泥制备砷酸钠和焦锑酸钠

采用Na2S作浸出剂,在强碱性介质中浸出黑铜泥中的砷和锑,继续保持强碱性条件,用H2O2氧化浸出液,使砷、锑分离,分别制备砷酸钠和焦锑酸钠。浸出渣可以返回熔炼主流程。     

Sodium Inhibition of Thermophilic Methanogens

This study investigated the sodium inhibition of methanogens using two thermophilic (55°C) anaerobic sequencing batch reactors (ASBRs). The ASBRs were operated at a chemical oxygen demand (COD) loading of 4 g/L/day and a hydraulic retention time of 3 days. To evaluate the chronic toxicity of sodium to methanogens, the biomass in one of the ASBRs was acclimated to increasing sodium concentrations of 4.1, 7.1, and 12.0 g/L while the feed to the second ASBR was not supplemented with any additional sodium. The methanogenic activity (mL CH4/g volatile suspended solids/day) decreased by nearly 44% at an acclimation concentration of 12.0 g Na+/L, but the COD removal efficiency and methane production did not vary appreciably at the different acclimation concentrations studied. The acute toxicity of sodium to methanogens was determined by a series of batch anaerobic toxicity assays (ATAs). The biomass acclimated to different concentrations of sodium was collected from the ASBRs and used as inocula for the batch tests, and the sodium concentration was varied up to 17.7 g/L. The methanogens in the biomass acclimated to 0, 4.1, 7.1, and 12.0 g Na+/L were completely inhibited (100% inhibition) at predicted sodium concentrations of 10.6, 12.7, 18.0, and 22.8 g/L, respectively. To simulate the results of batch ATA in the ASBR, 7-day feeding with sodium concentrations in the influent measuring 6.2, 10.6, and 16.0 g/L were introduced into the reactor. Among each feeding, the reactor was operated with no additional sodium in the feed with 2–3 week intervals. Even though the methanogenic activity was not significantly affected at 6.2 and 10.6 g/L of sodium, there was a deterioration in methanogenic activity at 16.0 g/L dosage of sodium.     

巯基乙酸钠替代氰化钠浮钼工业试验探索

氰化钠是浮选金属矿物的重要抑制剂之一,但是在使用过程中存在对人体和环境的潜在危害。试验介绍了栾川某钼矿选矿厂在铜钼分离中使用新药剂巯基乙酸钠替代氰化钠选钼的工业试验情况,结果表明巯基乙酸钠在钼矿浮选中能有效抑制铜,单独使用该药剂时,可以得到品位合格的钼精矿,但抑铜效果不稳定。同时指出了巯基乙酸钠在选厂铜钼浮选分离使用过程中应该注意的问题和改进措施,建议选用传统药剂氰化钠与新药剂巯基乙酸钠按比例混合使用的方式,达到综合抑制的效果。     

Leaching of Chalcopyrite with Sodium Hypochlorite

A laboratory study was conducted on the leaching of chalcopyrite with NaOCl (sodium hypochlorite). Experiments were carried out in the following two stages: (1) Chalcopyrite was converted to CuO (cupric oxide) with a sodium hypochlorite solution, and (2) cupric oxide was dissolved to cupric ions with 1 normal sulfuric acid at room temperature. In the first-stage leaching, the initial pH varied from 12.5 to 13.7, the temperature from 35 °C to 75 °C, the sodium hypochlorite concentration from 0.2 to 0.85 molar, and the chalcopyrite dosage from 1 to 10 g/500 ml. The leaching conversion showed a maximum (68.3 pct) around a pH of 13.2 at 0.5 molar OCl^– (hypochlorite) concentration and at 65 °C in 1 hour. The reagent consumption ratio—defined as the number of moles of hypochlorite consumed to leach 1 mole of chalcopyrite—was much higher than its stoichiometric ratio of 8.5. It reached 57.6 when the solid dosage was 1 g/500 ml and decreased to 12.9 when the solid dosage was increased to 10 g/500 ml. The leaching rate of chalcopyrite in the first stage was controlled by a chemical reaction with the activation energy of 50.2 kJ/mol (12.0 kcal/mol). A leaching scheme was identified in which 98 pct of the chalcopyrite was leached by adding hypochlorite stock solution stepwise in less than 3 hours.