Thermodynamics of Iron Oxidation in Metallurgical Slags

The state of oxidation of a pyrometallurgical process, given by the partial pressure of oxygen and the temperature, is one of the important properties monitored and controlled in the smelting and refining of iron and the nonferrous metals. This article reviews the thermodynamic background for this quantity and examines some empirical methods for its estimation and use. The emphasis is on copper smelting, but the same principles apply to iron, nickel, lead, and zinc processes.     

Equilibria of Sulfur and Oxygen Between Liquid Iron and Open Hearth-Type Slags

Data of several studies on the equilibrium between molten iron and open hearth-type slags have been combined to determine some of the chemical reactions involved in steel-making. Effects of slag composition and temperature on the iron oxide activity, distri-bution of sulfur between slag and metal, and the carbon content of the metal are dis-cussed. Also, an overall reaction for the equilibrium between sulfur and oxygen is presented.     

Amounts and Distribution of Phases in Sulfide Plus Oxide Scales on Iron

Pure iron was exposed at 800°C to flowing, catalyzed-gas mixtures of N₂/CO₂/CO/SO₂ adjusted to control the partial pressures of SO₂, S₂ and O₂. The equilibrium gas compositions were such that iron oxide was thermodynamically stable with respect to sulfide. The reaction product scale was invariably a mixture of oxide plus sulfide, and grew according to parabolic kinetics at high P_SO2 values and by linear kinetics in dilute gases. In both cases the reactant gas species was SO₂, not molecular oxygen or sulfur. The relative amounts of sulfide and oxide corresponded to stoichiometric reaction of SO₂ at high P_SO2 values, but not in dilute gases. At low P_SO2 values, the relationship between scale-sulfide volume fraction and P_SO2 corresponded to two independent scale-SO₂ reactions leading to oxide and sulfide growth. The two-phase mixture was lamellar, with platelets oriented approximately parallel to the mass-transfer direction. An inverse relationship between lamellar spacing and linear scaling rate is interpreted as evidence of a cooperative (cellular) growth mechanism.     

Steel from Copper Slags

A significant step toward the completion of plans for one of the largest steel mills in the Pacific Northwest was made with the initial prototype run at Strategic Materials Corp’s pilot-plant at Niagara Falls, Ontario, Canada. The operation utilized a modification of the Strategic-Udy process to produce steel from waste copper slags.     

Mechanisms of Metal Entrapment in Slags

This paper describes an experimental investigation into the transport of matte or metal into slags and a study of the mechanisms by which the metal or matte remains entrapped in the slags. The particular transport mechanism considered is transport by gas bubbles across metal/slag on matte/slag interfaces.     

高硫高铁难选铅锌矿选矿试验研究

针对高硫高铁铅锌矿的矿石特点,采用新型活化剂X-41和捕收剂Y-37,有效解决（铁）闪锌矿与（磁）黄铁矿分选的技术难题,显著提高锌精矿质量和回收率,采用组合抑制剂P-30,实现硫砷分离工艺技术的突破,提高了含砷高硫化矿的选矿效益。     

大型铸钢件渣罐的制造

为生产大型铸钢件渣罐,设计制作了高箱带高强度盖箱,采用两台电弧炉同时熔炼、原地清砂、原地气割冒口等措施,解决了无法生产此铸件的问题。通过工艺分析,选择适当的浇冒口系统、浇注温度等,生产出符合设计要求的合格铸钢件。     

大型铸钢件渣制度的制造

为生产大型铸钢件渣罐，设计制作了高箱带高强度盖箱，采用两台电弧炉同时熔炼、原地清砂、原地气割冒口等措施，解决了无法生产此铸件的问题。通过工艺分析，选择适当的浇冒口系统，浇注温度等，生产出符合设计要求的合格铸钢件。     

负压消失模铸造铸铁合金液充填性能及影响因素

研究了模样材料、负压度、浇注温度、浇注系统尺寸等对消失模铸造中铸铁合金液充填性能的影响，提出了改善铸铁合金液充填能力的途径。     

Surface Structure of Nonoxidizing Slags Containing Sulphur

Application of surface tension measurements has been made to molten silicates in order to determine the effect of sulphur upon the surface tensions of synthetic blast furnace slags. In melts with the same molar ratios of Al2O3 + SiO2 to the basic oxides BaO, CaO, and MgO, the surface tensions increase in the order of oxides listed. Sulphur lowers the surface tensions of the basic BaO, basic CaO, acid BaO, acid CaO, and acid MgO slags in that order; and the concentration of excess sulphur at the slag surface increases in this same order of slags. The rate and amount of desulphurization of iron by these slags is favored by a low excess surface sulphur in the slag.     

Some Notes On Oroya Copper Slags

This paper is a study of the interrelationship between copper and magnetite content of reverberatory slags. During an experimental run converter slag was withheld from a reverberato ry, resulting in much cleaner waste slags. The possibilities of treating converter slags outside the normal copper smelting circuit are briefly discussed.     

细直径型腔中灰铸铁铁液充型能力研究

结合Flemings提出的液态合金停止流动机理与凝固理论，建立了细直径型腔中灰铸铁铁液充型能力的计算模型。采用该模型理论预测了灰铸铁铁液的充型能力，并采用正交试验方法，研究了浇注温度、铸型温度、压头高度和型腔截面半径对铁液充型能力的影响规律。结果表明，新建理论模型能够较好地预测灰铸铁铁液在细直径型腔中的充型能力，预测结果与试验结果相吻合，发现影响充型能力的各因素的显著性由高到低依次为：型腔截面半径、浇注温度、压头高度、铸型温度。     

Preventing Iron Sulfide from Precipitation in Immersion Electric Pumps as a Result of Hydrogen-Sulfide Corrosion of Oil-Well Equipment

The study shows that, in oil wells, it is the moist hydrogen-sulfide corrosion of the casing string (especially of its longest section—from the electric immersion-pump's intake port to the well collar), the products of which fall immediately to the pump, thus irreversibly clogging it with iron sulfides. Two ways of preventing the clogs are proposed: (1) regularly and completely cleaning the inner surface of the string from the corrosion products and (2) creating a filter-accumulator in the form of a sufficiently tall layer of thickened oil, which floats above the dynamic level of the oil-pool liquid between the casing and tubing strings. The layer is opportunately pumped out together with sulfide–carbonate sediments fallen in it, and replaced with another one. Both methods were successfully applied to working oil wells in Bashkortostan.     

从锌浸出渣中浮选回收银的实践

湿法炼锌产生的酸浸渣中含有一定量的有价金属银,通过添加药剂改善物料表面性质,采取浮选法回收银,达到综合回收、提高企业效益的目的,并根据生产实践中影响银回收率出现的问题,对设备、工艺进行改造和改进,使得银回收率大幅提高。     

电渣重熔冶金过程炉渣黏度性能研究

CaF2-CaO-Al2O3-SiO2-MgO五元渣系在连铸保护渣、电渣重熔、有色冶金等高温熔炼过程有着广泛的应用。本文利用RTW-10熔体物性测定仪,通过五因素四水平正交实验设计法,得出CaF2-CaO-Al2O3-SiO2-MgO渣系的黏度随温度的变化数据及各成分对黏度性能的影响规律,从而为电渣冶金的实际应用过程提供理论依据。     

铝酸钙脱硫渣系的实验研究

在实验室的条件下,对用CaO、Al2O3、CaF2为原料配制的钢水脱硫剂进行了实验研究.研究发现,增加预熔脱硫剂量,可提高脱硫速度,增大脱硫率.提高钢水温度可以增大脱硫效率,在1620℃下,10min就可将钢液中的硫降低到0.026wt%的较低水平.添加CaO的铝酸钙预熔渣的脱硫效果明显优于纯12CaO·7Al2O3渣系,加氧化钙含量为10wt%时,整体脱硫效果最好.此预熔合成渣原料将可能成为一种高效、快速、环保的脱硫剂.     

锻造过程中硫化物变形行为的研究

研究了Ｓ－Ｃａ复合系易切削钢中硫化物在锻造过程中的变形行为。结果表明：由于Ｃａ对硫化物的变质作用，使得硫化物在锻造过程中产生不均匀变形，从而导致硫化物断裂细化，增加锻造比有利于硫化物的分布和形态的进一步改善。     

硫化物固体润滑涂层的研究现状

硫化物（FeS、WS2和MoS2）是固体润滑材料中重要的一种材料,由于其呈六角形晶体层状结构,分子层间结合力较弱,界面分子层极易滑动形成良好润滑性能,因而备受研究者的关注。本文在综合大量文献资料的基础上,对硫化物固体润滑涂层特性、润滑机理及最新制备工艺研究现状进行综述,并对硫化物固体润滑涂层的研究前景进行展望。     

"我国古代大型铁铸文物"系列文章之七古代大铁锅和大铁缸

分别叙述了我国古代大铁锅和大铁缸的功用、发展历程和现况。重点介绍了若干铁铸“千僧锅”和其它大铁锅以及若干大铁缸的尺寸、铸造年代和特点等情况，并阐述了古代大铁锅和大铁缸的铸造工艺。