Dechlorination of zinc dross by microwave roasting

Traditional treatments of zinc dross have many disadvantages,such as complicated recovering process and serious environmental pollution.In this work,a new process of chlorine removal from zinc dross by microwave was proposed for solving problem of recycling the zinc dross.With better ability of absorbing the microwave than zinc oxide,the main material in zinc dross,chlorides,can be heated and evaporated rapidly during microwave roasting.Various parameters including roasting temperature,duration time and stirring speed were optimized.The microstructure of roasted materials was characterized by X-ray diffraction（XRD） and scanning electron microscope（SEM）.The content of the chloride was analyzed by the method of chlorine ion selective electrode.The experiments indicate that the best duration time is 60 min with a stirring speed of 15 r/min during the microwave roasting process.The dechlorination rate reaches peak value of 88% at 700 ℃.The chlorine is removed as HCl gas when water vapor is used as activating agent,which means that it can be recovered into hydrochloride acid.     

Removing chlorine of CuCl residue from zinc hydrometallurgy by microwave roasting

Most Zn hydrometallurgy factories adopt Cu2SO4 as a dechlorination reagent from zinc solution nowadays, thus much CuCl residue is produced. The existing process of treating this residue is washing with water or sodium carbonate solution, which would cause a lot of troubles to water treatment and waste discharge. A method of microwave roasting was adopted for dechlorination of CuCl residue. A 1.5 kW microwave roasting equipment with dust collection and tail gas adsorption systems was set up and applied during the experiment. By investigating the effect of temperature, heat preservation time, moisture content of raw material and grain size of samples on the dechlorination, the optimal experimental condition is obtained. When the samples with 2% moisture and 〈150 μm grain size are microwave roasted at 400 °C for 2 h, the Cl content turns from 14.27% to 1.35% and the dechlorination rate is as high as 90%, while that with conventional heating is only 60%-80%. The phase change of the roasting process investigated with X-ray diffraction verifies that CuCl in CuCl residue is removed by being transformed into CuO.     

Homogenization of temperature field and temperature gradient field

The homogenization of temperature field and temperature gradient field are very important for many devices, systems and equipments, such as satellites and electronic devices. This paper discusses the distribution optimization of the limited high conductivity material with the simulated annealing algorithm to homogenize the temperature field in a two-dimensional heat conduction problem. At the same time, the temperature gradient field is homogenized with the bionic optimization method. The results show that ...     

微负压蒸氨法合成超细碱式碳酸锌的工艺研究

以精制碳酸铵锌溶液为原料,采用微负压蒸氨方法合成超细碱式碳酸锌.分析了不同工艺条件下对产品主成份含量、堆积密度及晶体粒径的影响,控制过程条件可以得到超细产品,粒径小于200nm,锌的析出率大于98.0%,产品的主成份Zn小于57.5%.     

一个充分下降的共轭梯度法

共轭梯度法是优化方法中最常用的方法之一,适于解决大规模问题,因此有着广泛的应用.针对无约束优化问题,基于搜索方向的选择,提出了一个新的共轭梯度法,该算法在每一次迭代过程中,均可保证搜索方向的充分下降性,并在弱的wolfe条件下,证明了算法的全局收敛性,数值结果表明了算法的可行性与有效性.     

恒温消化原子荧光法测定面粉中的痕量铅

研究了恒温消化发生原子荧光恒温消化法测量面粉中的痕量铅含量,采用DTD-30恒温消解仪于90℃预消解35 min,180℃消化35 min除去残酸。采用AFS-230E型双道原子荧光光度计,采用氢化物—原子荧光法测定面粉中的铅含量,实验确定了最佳测定条件。该法测定面粉中铅含量的相对标准偏差RSD为1.35%（n=9）,检出限为0.1 ng/mL。铅的线性范围为0～30 ng/mL,相关系数大于0.998。加标回收率为106.92%。     

化学沉淀法制备超细二盐基亚磷酸铅粉体

本研究采用化学沉淀法制备超细二盐基亚磷酸铅粉体,讨论了各种因素对二盐基亚磷酸铅颗粒度的影响。利用透射电子显微镜、激光粒度分析仪和X射线衍射仪等分析手段对粉体进行了表征。结果表明选择合适的反应介质、分散剂及搅拌速度可以得到粒径280nm左右的二盐基亚磷酸铅超细粉体。     

化学沉淀法制备超细二盐基亚磷酸铅粉体

本研究采用化学沉淀法制备超细二盐基亚磷酸铅粉体，讨论了各种因素对二盐基亚磷酸铅颗粒度的影响。利用透射电子显微镜、激光粒度分析仪和x射线衍射仪等分析手段对粉体进行了表征。结果表明选择合适的反应介质、分散剂及搅拌速度可以得到粒径280nm左右的二盐基亚磷酸铅超细粉体。     

修正Armijo线搜索下共轭梯度法的收敛性

为解决传统线搜索下没有全局收敛性,提出修正Armijo线搜索下共轭梯度法。通过估计目标函数导数的Lipschitz常数,能在每一步迭代中找到合适的步长,以保证全局收敛性,提高实际运算中的有效性。     

广义Wolfe线搜索下共轭梯度法的全局收敛性

共轭梯度法是求解大规模约束问题的有效算法,不同的参数选取构成不同的共轭梯度法.通过研究一个新的求解无约束最优化问题的共轭梯度法,证明该公式在广义Wolfe线搜索下是具有充分下降性,并且是全局收敛的.     

Wolfe搜索下广义共轭梯度法及其全局收敛性

指出了文献[10]中两类共轭梯度法的错误证明,提出了Wolfe搜索下一类以DY公式为上界的广义共轭梯度法,该算法在每一步不依赖于任何搜索自行产生充分下降方向,在适当的条件下证明了算法的全局收敛性.     

Statistical evaluation and optimization of zinc electrolyte hot purification process by Taguchi method

The neutral zinc sulfate solution obtained from hydrometallurgical process of Angouran zinc concentrate has cadmium, nickel and cobalt impurities, that must be purified before electrowinning. Therefore, cadmium and nickel are usually cemented out by addition of zinc dust and remained nickel and cobalt cemented out at second stage with zinc powder and arsenic trioxide. In this research, a new approach is described for determination of effective parameters and optimization of zinc electrolyte hot purification process using statistical design of experiments. The Taguchi method based on orthogonal array design(OAD) has been used to arrange the experimental runs. The experimental conditions involved in the work are as follows: the temperature range of 70-90 ℃ for reaction temperature(T), 30-90 min for reaction time(t), 2-4 g/L for zinc powder mass concentration(M), one to five series for zinc dust particle size distributions(S1-S5), and 0.1-0.5 g/L(C) for arsenic trioxide mass concentration. Optimum conditions for hot purification obtained in this work are T4(85 °C), t4=75 min, M4=3.5 g/L, S4(Serie 4), and C2=0.2 g/L.     

用转炉红热钢渣处理宝钢高锌含铁尘泥

介绍了利用转炉红热钢渣处理宝钢高锌含铁尘泥冷固结自还原球团的BSR法工业试验研究.结果表明,钢渣显热可以有效地将高锌含铁尘泥脱锌并熔融还原成可代替废钢使用的粒铁产品.由于不需要专门的熔炼设备,投资、成本较低,是一种很有竞争力的回收钢铁厂尘泥的新技术.     

偏最小二乘-分光光度法同时测定锌铜镍

研究了用偏小二乘(PLS)分光光度法同时测定水体中的Zn2+、Cu2+和Ni2+的方法,并与P矩阵、K矩阵、多元线性回归进行了比较.结果表明,PLS法简便快捷,测定结果更加准确可靠.     

Hot-forging die cavity surface layer temperature gradient distribution and determinant

Based on the car front-wheel-hub forging forming process of numerical simulation, the temperature gradient expression of forging model cavity near the surface layer was got ten, which illustrates that the forging temperature gradient is related to forging die materials thermal conductivity, specific heat and impact speed, and the correlation coefficient is 0.97. Under the different thermal conductivity, heat capacity and forging speed, the temperature gradient was compared with each other. The paper obtained the relevant laws, which illustrates the temperature gradient relates to these three parameters in a sequence of thermal conductivity > impact speed> specific heat capacity. To reduce thermal stress in the near-surface layer of hot forging cavity, the material with greater thermal conductivity coefficient and specific heat capacity should be used.     

自适应陷波滤波器的并网逆变器相位超前补偿方法

逆变侧电流反馈控制的LCL型并网逆变器广泛地应用于实际中,然而在数字控制下,控制延时改变了系统的相位特性,进而影响系统的稳定性。为此,提出了一种基于自适应陷波滤波器(adaptive notch filter,ANF)的相位超前补偿方法。首先,利用陷波器的相位超前环节对控制延时产生的相位滞后进行补偿,从而避免系统相位在谐振频率处穿越-180°,改善了系统的稳定性并增强其对弱电网的鲁棒性。其次,采用ANF算法对系统的谐振频率进行估计,并根据估计值动态调整陷波频率,扩大了谐振频率稳定区间,进一步提高了系统对LCL参数波动的适应能力。最后,对所提方法进行实验验证,结果表明:基于ANF补偿方案的并网逆变器稳定性良好,且相比传统的陷波方案,该方案对电网阻抗及LCL参数波动具有更好的鲁棒性,更利于LCL并网逆变器在弱电网工况下的控制。     

锌离子强化二级磷浮法对原糖回溶糖浆脱色的研究

为研究锌离子强化二级磷浮法对原糖回溶糖浆的脱色效果,以质量分数为30％的原糖回溶糖浆为研究对象,以脱色率为指标,通过单因素实验分别考察了锌离子质量浓度、磷酸质量浓度、反应温度及pH等因素对脱色率的影响,并通过正交试验获得最优的工艺条件;同时,结合Zeta电位、红外吸收光谱、XRD等表征手段就相关机理进行了探讨.实验结果...     

金矿排污渠周围土壤中Mn,Cu,Zn和Pb四种重金属的污染分析

以潼关县某金矿排水沟附近土壤为研究对象,对土壤中Mn,Cu,Zn和Pb四种重金属含量进行分析,为金矿周围土壤污染治理及人工生态修复提供依据。实验结果表明：Pb含量在研究区内累积严重,Cu次之,而Mn累积较轻;四种重金属在第四样区内的含量变化均最大,变异系数均最高;四种重金属在35个样点的分布特征中,Mn,Cu,Zn和Pb在样区内含量变化规律相似,可能存在相同或相近污染源。     

共轭投影梯度滤子算法及其全局收敛性

提出了一种基于共轭投影梯度思想的SQP-滤子算法,滤子技术的引入使得该算法不需要求解二次规划子问题.借助于共轭投影梯度思想能有效避免常规滤子算法中的恢复算法,简化了算法结构.在一定条件下,证明该算法具有全局收敛性.