粉煤灰、铝土矿电热法生产铝硅铁合金的试验

为改善环境，合理利用资源，应用粉煤灰、铝土矿、碳粉混合造球，球团干燥后放入中频感应炉进行熔炼，熔炼过程中加入铁矿粉和生铁块。研究结果表明：合金中铝的含量越高，其回收率越低。合金中铝的含量为24．67％时，铝的回收率高达61．91％，硅含量为18．42％时，硅的回收率高达92．51％。影响铝、硅回收率的主要因素为配铁量、熔炼温度和还原剂用量，熔炼温度控制在1800—1900℃为宜。     

硅的添加顺序对金属损耗影响的研究

对铸造铝硅合金熔炼过程中两种硅的添加方式,进行了预添加硅和后添加硅的熔炼试验,试验结果表明:两种不同的添加顺序直接导致了金属硅不同的实收率,后添加金属硅的实收率较预添加实收率高,能有效减少金属损耗。     

铝硅合金低温加硅研究

扼要介绍了铝硅合金生产中的五种熔配工艺,以共晶型与过共晶型两种不同牌号的铝硅合金为例阐述了低温加硅熔炼技术,获得了最佳工艺,该方法质量稳定、节约能源、环境友好。     

利用煤系高岭土电热法生产铝硅合金的节能研究

利用煤系高岭土、烟煤和黏结剂经球团处理后，在大型矿热炉中直接电热还原生产高硅铝硅合金，进而用纯铝稀释成各种牌号的铸造、压铸铝硅合金，是目前唯一区别于利用电解铝、金属硅掺兑生产铝硅合金的工业化技术。同时从节能方面阐述了电热一步法直接从矿石中获取有用金属的优势。     

稀土在铸造铝硅合金中应用的探讨

铸造铝硅合金的比重是铜合金及铸铁的1/3左右,比强度较高,耐蚀耐磨性较好,熔点低、熔炼能耗少,再生回收容易。铸造性能及使用性能优于其它铸造铝合金。但含硅>4.5%的铸造铝硅合金,具有收缩率小、流动性好、气密性好、热裂倾向小等优良的铸造性能,还有良好的物理机械性能及切削加工性能。所以,铸造铝硅合金     

高硅锰硅合金的生产

简要介绍了生产高硅锰硅合金中应注意的几个问题，即要有较高的炉温，合适的渣型，正确的熔炼操作。     

铝矿处理并直接电解生产铝硅钛合金（一）

我国铝土矿资源特点是高硅高钛低铁的—水硬铝石型。根据其矿物组成和化学组成的不同,可以采用酸法除铁或重选—磁选工艺除铁,煅烧后直接电解获得铝硅钛合金。经12KA和60KA电解槽工业试验,结果表明工艺可行,操作运行正常,产品化学组成稳定,综合成本低于纯铝。直接电解所得铝硅钛合金作为中间合金,配制成各种含钛铸造合金,经大量试验表明,其综合性能,特别是强度、耐磨及热稳定性优于相应的国家标准牌号合金。铝矿处理直接电解生产铝硅钛合金项目从原料处理、电解到合金应用都已通过工业规模试验。结果表明,该新工艺流程短、投资省、能耗和成本低,实现了铝士矿的综合利用,具有明显的经济和社会效益。     

吹氧强化电硅热法熔炼中碳锰铁过程的探讨

前言用传统的电硅热法熔炼中碳锰铁有很多优点:其一,熔炼硅锰合金的操作比较容易,并可使用SiO_2高的贫锰矿;其二,中碳锰铁冶炼过程中的脱硅较容易,所需温度亦较低,合金终点成份易于控制,有利于炉衬的维护;其三,中碳锰铁炉渣可用于炼制硅锰     

永登铝业液态铝硅直接熔配铝硅合金项目试产成功

河南永登铝业有限公司自主研发的铝硅合金生产新工艺——利用液态铝硅直接熔配铝硅合金项目经过3个多月的试生产和工艺完善,项目宣告试产成功,经行业专家评价技术属国内首创。     

氯化锰去除铝硅合金中铁杂质的研究

针对电热法生产的一次铝硅合金经稀释精炼后需去除杂质铁,而直接加锰除铁造成了锰的损失,且锰的扩散较慢这一问题。探讨了用氯化锰代替单质锰去除铝硅合金中铁的可能性。结果表明,氯化锰能够与铝反应生成锰即氯化锰可以代替锰去除铝硅合金中的铁。     

高铅渣直接还原炉的研发设计

概述了现有的粗铅冶炼工艺和高铅渣直接还原方法,介绍了电热焦炭直接还原炉、侧吹熔融还原炉、底吹电热熔融还原炉3种高铅渣直接还原炉的研发设计.     

Melting of oxidized nickel ores in a barbotage unit: I. Thermodynamic analysis of melting

The possibility of effective processing of oxidized nickel ores (ONOs) to form ferronickel in a barbotage unit (Vanyukov furnace for liquid bath melting (LBM)) is theoretically corroborated. The heat balances of the LBM processing of unreduced ONOs or the cinder preliminarily reduced in tubular kilns to form ferronickel are calculated. It is shown that deep reduction of ONOs and melting of the reduced cinder are energetically more favorable than direct melting of a slightly dried ore to form ferronickel. The proposed twostage scheme of processing of ONOs makes it possible to decrease the furnace area and the effluent gas flow. Parallel reduction and oxidation processes in the same region of a bubbled slag melt during direct melting of unreduced ore is debatable.     

等离子熔炼炉及其应用

本文根据文献资料，介绍等离子熔炼炉的基本结构特点、类型和应用，并介绍用于高纯钛合金熔炼的等离子冷床熔炼炉以及美国Lectrotherm公司发明的一种等离子炬与直接电弧电极相结合的冷床熔炼技术。     

Melting and crystallization behaviour of W-V-Si high-speed steels

Differential thermal analysis was used to determine the effects of variable Si, W and C contents on the behaviour of W-V-Si highspeed steels during melting and crystallization and to develop certain fragments of pseudobinary phase diagrams corresponding to melting and crystallization of these materials. Melting of S 9-0-2 steel involves the following sequence of transformations: reverse three-phase eutectic reaction, direct melting of austenite grains, reverse three-phase and then four-phase peritectic reactions, and melting of high-temperature ferrite. In steels containing more than 2% Si reverse four-phase peritectic reaction occurs immediately after partial completion of reverse eutectic reaction and in steels with more than 4% Si there is also direct melting of carbides. A decrease in tungsten content from 9.5 to 7 % in steels containing 2 % Si and 1.05 or 0.9 % C enhances direct melting of austenite grains; an increase in tungsten content to 12% inhibits this reaction completely. A decrease in carbon content from 1.05 to 0.9 % in steels containing W 7-12, V 2.5 and Si 2 % does not change the nature of transformations on melting. Crystallization of conventional S 9-0-2 steel involves the following sequence of events: formation of high-temperature ferrite crystals from the liquid, three-phase peritectic reaction, direct crystallization of austenite from the liquid, and three-phase eutectic reaction. With silicon contents exceeding 3% direct crystallization of austenite and three-phase eutectic reactions occur simultaneously. This sequence of reactions is not affected by reduction of tungsten content from 9.5 to 7 % in steels containing 2% Si and 1.05 or 0.9% C. An increase in tungsten content to 12% in such materials results in complete inhibition of direct crystallization of austenite from the liquid and in 1.05% C steel there is an additional change involving simultaneous occurrence of three-phase peritectic and eutectic reactions. A decrease in carbon content from 1.05 to 0.9% in steels containing 7–12% W and 2% Si does not change the nature of transformations during cooling but does enhance partially simultaneous occurrence of three-phase peritectic and eutectic reactions.     

Video detection of problems in the melting of consumable electrodes in a vacuum arc furnace

Methods are proposed for the detection of problems in vacuum arc melting. Video cameras are mounted on the vacuum arc furnace in order to monitor the melting process. Usually, the automatic control system for the melting process only measures the quantities required for direct control. In some cases, those measurements do not permit the detection of specific nonstandard melting conditions. However, on the basis of the video images, the supervisor can identify and eliminate such problems. The video feed is divided into frames. Each frame is a matrix consisting of pixels. On the basis of the sum of pixels in the image, anomalous melting conditions may be determined. Algorithms are proposed for analysis of the video images so as to detect anomalous melting conditions.     

转底炉直接还原铜渣回收铁、锌技术

采用转底炉直接还原工艺,将铜渣含碳球团在高温条件下直接还原得到金属化球团和高品位氧化锌粉尘,再通过熔分或磨矿磁选方式将铁回收,得到的铁产品可作为冶炼含铜钢的原料.转底炉中试结果表明:采用"转底炉直接还原—燃气熔分"流程处理铜渣,可获得TFe品位94%以上、铁回收率93%以上的熔分铁水;采用"转底炉直接还原—磨矿磁选"流程处理铜渣,可获得TFe品位90%以上、铁回收率85%以上的金属铁粉;采用两种流程处理铜渣,均可获得锌品位60.02%的ZnO粉尘.结果表明,经过转底炉直接还原,铜渣中的铁橄榄石Fe_2SiO_4和磁铁矿Fe_3O_4相转变为含有金属铁Fe、二氧化硅SiO_2和少量辉石相Ca(Fe,Mg)Si_2O_6的金属化球团,具备通过磨选或熔分进行进一步富集的条件.     

Theoretical model of the submerged arc welding process

Expressions for the direct current and melting rate of wire electrodes in the submerged arc welding process are derived via the principles of irreversible thermodynamics. The melting rate of the consumable wire electrode under quasi steady state conditions consists of eight contributions: 1) Peltier heating effect, 2) Arc heating effect, 3) Contact resistance effect, 4) Radiation heat transfer effect, 5) Joule heating effect, 6) Heat conduction effect, 7) Melting rate effect of electrolyte flux, 8) Melting rate effect of the sublayer zone. Application of the general theoretical melting rate to a limiting case of practical interest reveals good agreement between theoretical predictions and experimental results. The affect of polarity reversal on melting rate is explained in terms of thermionic emission phenomena.     

Application of Wood Char in Processing Oolitic High-phosphorus Hematite for Phosphorus Removal

Phosphorus removal from oolitic high-phosphorus hematite using direct reduction followed by melting sep-aration was investigated.At the direct reduction stage,highly volatile wood char was prepared by carbonizing j uj ube wood at 673 K for 2 h and was used as reducing agent.The results of the direct reduction tests show that at a tem-perature of 1 373 K,a char mixing ratio of 0?8,and a reduction time of 10-25 min,the briquettes reached a metal-lization degree of 80%-84% and a residual carbon content of 0?13-1?98 mass%.Phosphorus remained in the gangue as calcium phosphate after reduction.The results of the melting separation tests show that residual carbon in reduced briquette negatively affects the phosphorus content (w[P])in hot metal.When the reduced briquettes ob-tained under the aforementioned conditions were used for melting separation,hot metal suitable for basic oxygen steelmaking (w[P]<0?4 mass%)could not be obtained from metallic briquettes with a residual carbon content more than 1?0 mass%.In contrast,it could be obtained from metallic briquettes with residual carbon content less than 0?35 mass% by mixing with 2%-4% Na2 CO3 .     

Some Aspects of the Melting and Dephosphorization Mechanism of Hydrogen-DRI

To meet the future environmental challenges, hydrogen direct reduced iron (H-DRI) is expected to constitute the principal material for virgin steel production. For an efficient value chain, knowledge of the melting mechanism and dephosphorization mechanism of H-DRI is needed. The in situ melting behavior, the melting mechanism, and the dephosphorization mechanism during heating of H-DRI are investigated experimentally at 1773 and 1873 K. It is found that the melting rate of H-DRI varies with the reduction degree (91–99.5%), increasing with decreasing reduction degree. An autogenous slag forms during heating and flows through the pores of the H-DRI, thus increasing its effective thermal conductivity. The fraction of filled pores varies with reduction degree explaining the difference in melting rate. At this stage, the dissolution of apatite is initiated and completed upon melting of the metal phase. A gradual reversion of phosphorus from the autogenous slag to the liquid metal is observed after complete melting. The rate of reversion is discussed based on the properties of the H-DRI, for example, reduction degree and carbon addition.     

Peculiarities of the Microstructure and Properties of Parts Produced by the Direct Laser Deposition of 316L Steel Powder

Russian Journal of Non-Ferrous Metals - The direct laser deposition of metal powders is one additive method of producing functional materials. It consists of the melting of metallic powders by a...