ICP-AES法测定生铁中锰和硅

生铁是冶金行业必不可少的原料和产品,而生铁中锰、硅元素含量是生铁质量好坏的重要指标。传统的锰、硅含量分析方法[1-2],分析周期长,操作繁琐。本文采用稀硫酸溶解试样, ICP-AES法同时测定锰、硅,结果令人满意,适用于日常分析及X射线荧光光谱仪的控制标样分析。1实验部分1·1     

Demanganisation of high manganese pig iron to produce high manganese slag

Abstract

Pig iron with a high manganese content makes further processing to steel using converter technology difficult and unprofitable. In the present study, external demanganisation of high manganese pig iron before the oxygen converter process has been investigated. Pilot plant experimental heats were designed and carried out to optimise the demanganisation process, to produce hot metal adequate for the conventional LD converter, and high manganese slag suitable for the production of silicomanganese. Various high manganese pig irons with different [Si]/[Mn] contents were treated by injection of various oxidisers at varying temperatures, slag basicities and injection rates. The optimum conditions for the demanganisation process have been attained by injection of an oxygen gas–manganese ore mixture at the injection rate of 6.8 L min^-1kg^-1 into molten high manganese pig iron with a [Si]/[Mn] ratio of 0.3 at an initial temperature of 1350°C and slag basicity of 0.3–0.4.     

Thermodiffusion impregnation of iron and nickel powders with manganese

Summary A study was carried out on the thermodiffusion impregnation of iron and nickel powders with manganese from point sources at temperatures of 773–1373°K and holding durations of 2, 6, and 10 h, using charges containing 2–30% ammonium chloride. Manganese in the form of ferromanganese or metallic manganese was added to the charge in amounts ranging from 8 to 30%. It was demonstrated that the presence of excessive amounts of ammonium chloride in the charge leads to substantial manganese losses and is therefore undesirable. The optimum conditions have been established for the impregnation of iron and nickel powders with manganese.Translated from Poroshkovaya Metallurgiya, No. 6 (66), pp. 8–13, June, 1968.     

磺基水杨酸光度法快速测定锰矿石中铁

磺基水杨酸光度法是测定铁较常用的一种分析方法, 但由于锰离子对铁的测定有干扰, 因而实际工作中很少采用此法测定锰矿石中的铁。在pH 10左右的介质中, 铁与磺基水杨酸生成相对稳定的2∶1黄色络合物, 在420 nm处有最大吸收峰, 通过加入盐酸羟胺来消除锰矿石中锰的干扰, 据此建立了磺基水杨酸光度法测定锰矿石中铁的分析方法。采用实验方法对锰矿石国家标准物质(GBW07262和GBW07263)中的铁进行了测定, 测定值与认定值相一致, 相对标准偏差(RSD, n=5)分别为3.1%和1.1%。对锰矿实际样品进行了分析, 结果表明, 未加盐酸羟胺时, 测定结果严重偏高, 加了盐酸羟胺之后本法的测定结果与国家标准方法(GB/T 1508-2002)以及ICP-AES的测定结果基本一致。方法可用于各种品位锰矿石中铁的测定, 特别适合大批量样品的分析。     

低锰高铁矿直接还原-熔分制备富锰渣试验研究

摘要：试验以锰品位27.7%,铁品位18.1%的低锰高铁矿为研究对象还原制备富锰渣,生产得到的富锰渣可用于冶炼硅锰合金,以达到高效利用低品位锰矿的目的。根据该矿的成分分析、XRD分析和粒度检测分析结果,采用还原 熔分法对低锰矿进行还原制备富锰渣试验,试验结果表明：单因素试验下各参数对低锰高铁矿的还原-熔分后渣中Mn、Fe元素的含量和Mn元素的回收率均有较大影响,同时结合Box-Behnke原理设计方案,选取温度、碱度以及配碳量3个试验因素,通过响应曲面法研究各因素交互作用下对Mn元素回收率的影响规律,对试验因素进行优化分析,建立相应的多项式模型。模拟优化得到最优的工艺条件为：还原温度1402℃,碱度0.10,配碳量10.04%,Mn元素回收率为97%。在最佳条件下做验证试验得出Mn元素回收率为95.80%,误差1.24%,证明响应曲面法预测模型具有可靠性,同时对低锰高铁矿的应用有重要指导意义。     

Experimental study on preparation of manganese rich slag by direct reduction melting separation of low manganese high iron ore

In this experiment, low manganese high iron ore with manganese grade of 27.7% and iron grade of 18.1% was used as the research object to reduce and prepare manganese rich slag. The obtained manganese rich slag can be used for smelting silicon manganese alloy to achieve the purpose of efficient utilization of low grade manganese ore. According to the results of composition analysis, XRD analysis and particle size analysis of the ore, the reduction melting separation method was used to prepare manganese rich slag from low manganese ore. The experimental results show that each parameter has a greater impact on the mass fraction of manganese and iron in the reduction melting separation slag of low manganese high iron ore and the recovery rate of manganese under the single factor test. At the same time, combined with the Box Behnke principle design scheme, three experimental factors including temperature, alkalinity and carbon content were selected. The influence of each factor on the recovery rate of manganese was studied by response surface method. The experimental results were analyzed to establish the corresponding polynomial model, and the optimal process conditions were as follows: reduction temperature of 1402℃, alkalinity of 0.10, carbon content of 10.04%, and the recovery rate of manganese was 97%. A verification test was conducted under the optimal conditions; the recovery rate of manganese was 95.80%, and the error was 1.24%, which proved that the response surface method was a reliable and accurate prediction model. At the same time, the results are instructive for the application of low manganese and high iron ore.     

Protection against peroxynitrite by selenoproteins

Cellular defense against excessive peroxynitrite generation is required to protect against DNA strand-breaks and mutations and against interference with protein tyrosine-based signaling and other protein functions due to formation of 3-nitrotyrosine. We recently demonstrated a role of selenium-containing enzymes catalyzing peroxynitrite reduction. Glutathione peroxidase (GPx) protected against the oxidation of dihydrorhodamine 123 (DHR) by peroxynitrite more effectively than ebselen (2-phenyl-1,2-benzisoselenazol-3(2H)-one), a selenoorganic compound exhibiting a high second-order rate constant for the reaction with peroxynitrite, 2 x 10(6) M-1s-1. The maintenance of protection by GPx against peroxynitrite requires GSH as reductant. Similarly, selenomethionine but not selenomethionine oxide exhibited inhibition of rhodamine 123 formation from DHR caused by peroxynitrite. In steady-state experiments, in which peroxynitrite was infused to maintain a 0.2 microM concentration, GPx in the presence of GSH, but neither GPx nor GSH alone, effectively inhibited the hydroxylation of benzoate by peroxynitrite. Under these steady-state conditions peroxynitrite did not cause loss of 'classical' GPx activity. GPx, like selenomethionine, protected against protein 3-nitrotyrosine formation in human fibroblast lysates, shown in Western blots. The formation of nitrite rather than nitrate from peroxynitrite was enhanced by GPx, ebselen or selenomethionine. The selenoxides can be effectively reduced by glutathione, establishing a biological line of defense against peroxynitrite. The novel function of GPx as a peroxynitrite reductase may extend to other selenoproteins containing selenocysteine or selenomethionine. Recent work on organotellurium compounds revealed peroxynitrite reductase activity as well. Inhibition of dihydrorhodamine 123 oxidation correlated well with the GPx-like activity of a variety of diaryl tellurides.     

Simultaneous desulfurization and dephosphorization reactions of molten iron by soda ash treatment

Desulfurization and dephosphorization reactions of molten iron by soda ash has been studied on laboratory heats of Fe-C, Fe-C-S, Fe-C-P, and Fe-C-S-P alloys at 1573 and 1623 K. The alloys were melted in helium gas flow and preheated soda ash was added; metal samples were taken at certain time intervals and analyzed for sulfur, phosphorus, and carbon. Evolved gas samples were also taken at certain time intervals and analyzed. The phosphorus and sulfur contents in metals decreased rapidly, reaching the lowest values two to four minutes after the soda ash addition. The degree of desulfurization was generally greater than that of dephosphorization, and both degrees were higher at lower reaction temperature. The major component of evolved gas was CO with small amounts of CO₂. Phosphorus appeared to form a stable phosphate compound with Na₂O, possibly 3Na₂O-P₂O₅, in the slag phase. Soda ash reacts with carbon resulting in decarburization of molten iron and vaporization of sodium; this reaction may cause the fading of soda ash and can be expressed as: Na₂CO₃(1) + (1 +x)C = (1 -xNa₂O(1) + 2xNa(g_ + (2 +xCO(g). For the phosphorus containing melt, the reaction can be expressed as: Na₂CO₃(l) +yC + 2x/3P =x(Na₂O · 1/3P₂O₅)(1) + (2 −y − 8x/3)Na₂O(l) + 2(−l + y + 5x/3)Na(g) + (1 +y)CO(g) and for the sulfur containing melt: Na₂O(l) +C +S = Na₂S(l) + CO(g). Katsumi Mori, Formerly Visiting Associate Research Scientist, University of Michigan, Ann Arbor, MI     

ICP测定铁矿石中Mn含量的测量不确定度评定

对ICP测定铁矿石中Mn元素的测量不确定度的产生原因进行分析，并对铁矿石试样中Mn含量的测定结果的不确定度进行评定。     

电感耦合等离子体原子发射光谱法测定镍铜合金中锰和铁

提出了一种快速测定镍铜合金中的锰和铁的电感耦合等离子体原子发射光谱法(ICP-AES)。样品用硝酸溶解, 选择257.610 nm 和259.940 nm波长的谱线分别作为锰和铁的分析线, 运用基体匹配的校准曲线, 在优化仪器工作参数条件下测定, 基体和共存元素对测定没有干扰, 方法的检出限分别为0.001%(锰)和0.000 6%(铁)。方法用于镍铜合金标准样品中锰和铁的测定, 测定值与认定值一致, 相对标准偏差为1.0%(锰)和0.88%(铁)。     

Kinetics of manganese oxide reduction from basic slags by carbon dissolved in liquid iron

The reduction of manganese oxide from a basic slag by carbon dissolved in liquid iron is a slow reaction, failing to approach equilibrium closely in 20 hr. Furthermore, the rate of stirring has no apparent effect on the reaction rate. This identifies the rate-controlling step as a chemical reaction at the interface. Only the model for the reactionO ²⁻ =O + 2e ⁻ gave a consistent interpretation as the melt geometry, and concentration of manganese oxide and carbon were varied. The rate constant for this reaction was found to be 1.28 × 10⁻⁵ mole per sq cm per min at 155O°C. The effect of temperature is substantial with a calculated energy of activation for the system of 25 kcal per mole. Formerly Graduate Student, The University of Michigan This paper is based on a portion of a thesis submitted by W. L. DAINES in partial fulfillment of the requirements for the degree Doctor of Philosophy at The University of Michigan.