陕投集团建绿色清洁炼镁法厂

正陕西投资集团秦龙电力股份有限公司将采用东北大学开发的"一罐出清洁绿色炼镁"技术建一个生产能力120 kt/a的镁厂。此工艺在炼镁技术上有重大突破,是世界上最节能环保的炼镁法,它的还原时间由皮江法的10 h缩短到1～1. 5 h,镁的综合回收率由75%提升到大于90%,消耗标煤由5 t/t镁下降到(3～3. 5) t/t镁,CO2排放量由23 t/t镁降至(11～13) t/t镁,成本比皮江法的低30%以上。此工艺于2019年4月份以"绿色清洁炼镁技术与装备"项目通过了由中国有色金属工业协会     

略论皮江法炼镁工艺的改革

本文分析了皮江法炼镁工艺过程的特点,在综述国内外硅热法炼镁生产和试验研究进展情况的基础上,论证了皮江法工艺改革的出路在于将火焰外加热的还原炉,改变成电内热式还原炉,从而降低炼镁能耗,提高设备产能。     

我国皮江法炼镁工艺的技术差距和出路

本文介绍了世界产镁国的生产方法及今后西方国家镁的供需理及西方国家镁的发展，日本按皮江法炼镁的技术水平及其退出镁冶炼行业的原因，中国皮江法炼镁的技术水平与日本镁冶炼的差距；中国皮江法炼镁的出路；中国在皮江法炼镁工业发展中看法上的片面性等问题。     

我国皮江法炼镁工艺的技术差距和出路（1）

本文介绍了世界产镁国的生产方法及今后西方国家镁的供需量及西方国家镁的发展，日本按皮江法炼镁的技术水平及其退出镁冶炼行业的原因，中国应江法炼镁的技术水平与日本镁冶炼的差距；中国皮江法炼镁的出路；中国在皮江法炼镁工业发展中看法上的片面性等问题     

我国皮江法炼镁工艺的技术差距和出路（2）

我国皮江法炼镁工艺的技术差距和出路（２）徐日瑶（中南工业大学湖南长沙４１００８３）４我国皮江法炼镁的出路近两年来我国按皮江法生产镁的厂家已有数百家，其设计产量已超过４万ｔ，这些工厂生产效率一般较低，能耗高，成本高，产品质量一般也只能达到国标二级镁（９...     

热法还原镁的研究及液相Si-X体系还原镁的热力学分析

我国是金属镁生产和出口第一大国,皮江法热还原炼镁在我国金属镁生产中占据着绝对优势,但是其能耗高、污染大且效率低,成为影响镁行业持续绿色发展的限制因素.鉴于此,国内外针对皮江法进行了不断改进,并开发出新型炼镁工艺.液-液还原和固-液还原炼镁因其效率较高、周期短、能耗小等优点,成为热还原炼镁的重要发展方向.本研究基于固-液...     

中国皮江法炼镁工业环保问题的探讨

中国是世界上最大的原镁生产国。中国炼镁工艺主要以皮江法为主,该方法需要消耗大量的白云石和原煤,给环境造成了严重的污染。为此文章对中国皮江法炼镁工艺的产污环节进行了系统地分析,采用物料平衡法和类比法对废气、废水、废渣以及噪声的产污系数进行了核算,指出了该工艺中存在的主要环保问题。为了降低中国皮江法炼镁企业的能耗和物耗、减少污染物的排放、减轻对环境的污染,文章分别从工艺设备改进、清洁能源使用、污染物末端治理以及企业环境管理体系等方面提出了有效可行的措施。     

皮江法炼镁工艺还原罐内温度场研究

通过对皮江法炼镁工艺还原罐内传热介质的物性参数分析、物料传热分析、温度场的计算机模拟,研究了还原罐内热量传递规律和温度场分布规律,得出了皮江法还原罐内热量传递速率决定还原时间和生产效率的结论,并提出了改进我国皮江法炼镁工艺技术的思路。     

皮江法炼镁质量提升的实践

高质化原镁的生产是皮江法炼镁的方向，影响原镁质量的因素较多，解决必须从全过程抓起。     

我国硅热法炼镁现状及发展趋势

我国镁冶金工业是在特定的环境和条件下发展起来的，是以牺牲环境和燃料资源为代价的。目前，我国硅热法炼镁的发展趋势为开发高效、节能、环保的皮江法炼镁工艺。     

Assessing environmental impact of magnesium production using Pidgeon process in China

Based on the practice of magnesium production in China, a quantitative evaluation of the environment impact was carried out according to the theory and fi＇amework of life cycle assessment（LCA） study. The major gaseous pollutants including CO2, SO2, NO/, CH4, HF and particulates were calculated. The accumulative environmental performances of different energy use strategies and the characterization results, including abiotic depletion potential（ADP）, global warming potential（GWP）, acidification potential（AP） and human-toxicity potential（HTP） were compared. The results show that the direct emission of fuel combustion in the process is the major contributor to the pollutants emission of magnesium production. Global warming potential and acidification potential make the main contribution to the accumulative environmental impact. The different fuel use strategies in the practice of magnesium production cause much different impacts on the environmental performance. The accumulative environmental impact of coal burned directly is the highest, and that of producer-gas comes to the next, while that of coke-oven gas is the lowest.     

Numerical simulation for macrosegregation in direct-chill casting of 2024 aluminum alloy with an extended continuum mixture model

An extended continuum mixture model for macrosegregation is applied to predicting Cu and Mg segregation in large-size ingot of 2024 aluminum alloy during direct chill casting (DC). A microsegregation model using the approximate phase diagram data was coupled with macroscopic transport equations for macrosegregation profiles. Then, the impacts of transport mechanisms on the formation of macrosegregation were discussed. It is found that copper and magnesium have a similar segregation configuration from the billet center to surface. Negative segregation is observed in the centerline and subsurface, whereas positive segregation is obtained in the surface and somewhat underestimated positive segregation in the middle radius. Further, the discrepancy between the predicted and experimental results was discussed in detail. The results show that the magnesium to some extent alleviates the copper segregation in ternary alloy, compared with that in binary alloy. The predicted results show good agreement with measured experimental data obtained from literatures.     

还原酸浸法从低品位水钴矿中提取铜和钴

以Na2SO3为还原剂从水钴矿还原酸浸液中提取铜和钴,研究了还原剂种类及用量、浸出温度、硫酸浓度等因素对水钴矿还原酸浸过程中有价金属铜和钴浸出率的影响。结果表明,Na2SO3是较适宜的还原剂;在还原剂用量为水钴矿原矿质量的10%、硫酸浓度为3 mol/L、浸出温度为60℃、液固比为2-1、浸出时间为60 min的条件下,铜和钴的浸出率分别达99.06%和98.87%。并提出了"M5640萃铜→黄钠铁矾法除铁→碳酸钠除铝→氟化钠除钙、镁→蒸发结晶得钴产品"的后续分离净化流程,能有望应用于水钴矿及类似物料中有价金属的提取与分离的工业生产。     

镁/铜异种金属激光填丝熔钎焊接特性分析

对T2纯铜板与AZ31B镁合金板以搭接接头形式进行激光填丝熔钎焊试验,研究了等热输入下激光功率对镁/铜界面附近物相结构、分布和接头性能的影响. 结果表明,在适当的焊接工艺参数下可获得成形良好并具一定强度的镁/铜搭接接头,抗剪强度最大可达164.2 MPa,为镁合金母材的64%. 激光功率较低时,镁/铜界面主要为极薄的Mg-Cu共晶组织. 当激光功率较高时,从焊缝侧到铜侧,界面组织为α-Mg+(Mg,Al)2Cu共晶组织/Mg2Cu+Cu2Mg金属间化合物/Mg-Al-Cu三元化合物/Mg2Cu+Cu2Mg金属间化合物;焊缝侧到铜侧,硬度先增大而后突然减小,再缓慢增大,结合面附近达到最大硬度165 HV. 金属间化合物是影响焊接接头性能的主要因素,接头在此处发生脆性断裂.     

Sn对镁合金显微组织和力学性能的影响

研究了Ｓｎ对镁合金显微组织和力学性能的影响。研究结果表明,纯镁中加入Ｓｎ后能使纯镁铸锭中粗大的柱状晶转化为均匀的等轴晶,并有效地细化晶粒,同时在显微组织中形成具有立方Ｃ１结构的Ｍｇ２Ｓｎ颗粒相。由于Ｍｇ２Ｓｎ颗粒相显微硬度和熔点高,热稳定性好,因而对基体具有有效的弥散强化作用,提高了ＭｇＳｎ二元合金的室温及高温强度。在Ｍｇ９Ａｌ０．８Ｚｎ基合金中加入少量的Ｓｎ便能有效地提高合金的耐热性,而加入过多的Ｓｎ反而会导致合金高温强度下降。     

Evolution Behavior of γ-Al_(3.5)FeSi in Mg Melt and a Separation Method of Fe from Al–Si–Fe Alloys

The recycling of high Fe-content Al–Si alloys is a green industry. Eliminating the harmful effect of Fe,achieving the separation of Al and Fe is one of the key problems. Different from traditional methods for iron removal, a novel method using magnesium melt to separate Al and Fe is proposed. By introducing Al–14 Si–5 Fe alloy into Mg melt, it was found that the γ-Al_(3.5)FeSi phase evolves to Al_3SiFe_(3.5) and Al_5Fe_2 through the melting and solidification process.Compared with the primary Al-rich γ-Al_(3.5)FeSi phase, the formation of Fe-rich Al_3Si Fe_(3.5) is quite beneficial for the separation of Al and Fe. Mg–Si–Al and Mg–Si–Fe alloys can be obtained at the top and bottom of the cooled ingot,respectively. The results in this study provide meaningful suggestions for recycling scrap Al–Si–Fe materials.     

镁合金表面层层组装PSS/PAH膜诱导钙磷涂层

目的镁合金具有良好的生物相容性和可降解性,作为生物医用材料具有广泛的应用前景。有效地提高镁合金的耐蚀性能,对镁合金作为医用材料具有重要意义。方法利用浸泡法在AZ31镁合金基体表面层层组装制备聚苯乙烯磺酸钠(PSS)、聚丙烯胺盐酸盐(PAH)多层膜,并将获得的样品采用水热法在Ca(NO)_3、NaH_2PO_4、Na_2CO_3溶液中诱导钙磷涂层(羟基磷灰石)的形成。利用高分辨扫描电子显微镜、傅里叶红外光谱、X射线光电子能谱对Ca-P/(PAH/PSS)5/Mg复合膜层的表面形貌、化学成分进行了表征,通过析氢和电化学实验(包括极化曲线及阻抗谱)研究了Ca-P/(PAH/PSS)5/Mg涂层的耐腐蚀性能。结果Ca-P/(PAH/PSS)5/Mg膜层厚度约为7.67μm,表现为立体叶草状,在镁合金表面紧密排列。Ca-P/(PAH/PSS)5/Mg涂层耐蚀性提高一个数量级,其腐蚀电流密度从镁合金AZ31的3.69×10–5 A/cm2降低到1.61×10–6 A/cm~2,同时析氢速率降低。结论该涂层可以有效地提高镁合金的耐蚀性能,其成因则主要归功于组装的两种聚电解质的类生物矿化作用。这种诱导所得钙磷膜层对镁合金在生物医用领域的应用提供了新的思路。     

一种新螺杆挤压法从6063铝合金和Mg混合颗粒制备Al/Mg复合材料

采用一种新的螺杆挤压法以AA6063合金和工业纯Mg混合颗粒为原料制备Al/Mg双金属复合材料。加入铝合金中的镁合量最高可达到12.5%（质量分数）。所制备复合材料由细小晶粒组织组成。其显微组织中除有原料中的物相外,还观察到由γ-Mg17Al12包围的岛状Al2Mg3金属间合物。复合材料的强度随Mg含量的增加逐渐增高。含Mg为10%复合材料的极限抗拉强度最高,超过350 MPa。断裂表面分析结果表明,增加Mg含量导致材料发生较严重的脆性断裂及断裂机制的较小变化。因此,应对挤压工艺条件进行进一步优化。     

Microstructure character of AZ80 magnesium alloy ingots cast under electromagnetic vibration

Microstructure evolutions of an AZ80 magnesium alloy ingot with 300 mm in diameter cast with and without the electromagnetic vibration was investigated. The microstructures of the ingot cast with the conventional DC exhibited relatively fine dendritic grains at the surface area, but coarse dendritic grains at the 1/2 radius and large equiaxed dendritic grains at the center. However, under the electromagnetic vibration casting condition, the microstructures of the ingot is significantly refined, especially those at the surface and at the center.     

A new integrated lean manufacturing model for magnesium products

From an environmental point of view, lighter metals like aluminum and magnesium are unclean products to make; they require energy-intensive methods and increased greenhouse gas emissions as compared with steels. They are, however, clean to use, in particular in the transportation sector, if adequate weight savings and consequent fuel consumption reduction and CO₂ reduction can be achieved to offset the initial higher energy need. In order to reduce CO₂ emissions, better energy efficiency and substitution of low-carbon technologies are going to play a key role in future technical options. Modern research and development should be focused on promoting the efficient use of metallic materials according to the “dematerialization” concept design. Dr. D’Errico can be reached at fabrizio.