Metallurgical Development in Steel‐plant‐internal Multi‐injection Hot Metal Desulphurisation

The use of thermodynamic, statistical, and light and electron‐optical microscopic methods has made it possible to analyse the course of reactions during steel‐plant‐internal hot metal desulphurisation. The theoretical dependence between oxygen and sulphur activity has been used to develop an EMF‐measurement‐based technique for determining the sulphur content as the hot metal is desulphurised. The absence of magnesium sulphide from the collection of phases in the final slag because of the greater stability and secondary formation of calcium sulphide has been explained with the aid of thermo‐chemical calculations.     

The effect of chlorine and oxygen concentrations on the removal of mercury at an FGD-batch reactor

A series of laboratory scale experiments were conducted in an FGD-batch reactor. A synthetic flue gas was produced and directed through a CaCO₃ suspension contained in a glass reactor vessel. The suspension temperature was set at 54 °C through a water bath. In order to observe the distribution of mercury species in the system, solid, liquid and gaseous samples were taken and analysed. For gaseous mercury determination, continuous measurements were carried out, up and downstream the reactor. Furthermore, the concentration of chlorine in the scrubber solution of the system was varied from 0 to 62 g/l under different oxidative conditions.In a first approach, a concentration drop of elemental mercury coming out of the system was observed. The latter occurs only when high concentrations of Cl⁻ are present, combined with a high O₂ availability in the scrubber. It was also observed that mercury species distribution in the different phases varies, depending on the available chemical form of chlorine and oxygen concentration.     

Microbial mineral processing: The opportunities for genetic manipulation

Applications of microbiology to mining operations have been surveyed and evaluated. This has been carrried out with a view to seeking directions whereby genetical and molecular biological approaches could be applied to optimise ‘bio-mining’ processes. Copper and uranium are currently recovered from their ores on a commercial scale (to a value of about US$1800 million annually worldwide) using bioleaching systems carried out in the open in biologically uncontrolled conditions. Possibilities also exist for applying bioleaching methods on an industrial scale for the extraction of a number of other metals from sulphide-bearing concentrates. Molybdenum, cobalt and nickel are likely to be most suitable, principally because of their value. Biological ore beneficiation can be used to enhance the recovery of noble metals. Bioleaching systems offer a variety of desirable advantages compared to conventional methods but suffer principally in their relatively low leaching rates. Opportunities exist for the enhancement of bioleaching rates by genetic technologies. These approaches are outlined and discussed. Bioconcentration systems offer possibilities for metal recovery from dilute industrial waste streams and metal refinery effluents and for the heavy metal detoxification of polluted waters. Possible applications of genetic technologies to bioconcentration systems are proposed. Other uses for the mineral leaching thiobacilli, e.g. fossil fuel desulphurisation, are outlined and discussed.     

钢包喷粉脱硫过程中钢液内氮行为的研究

对８０吨钢包喷粉脱硫试验数据的统计分析，研究了该过程中钢液内氮含量与钢液化学成分、炉渣性质、钢液温度、喷粉参数等因素的关系。     

Physicochemical comparison of electroslag remelting with consumable electrode and electroslag refining with liquid metal

The paper is devoted to comparison of electroslag remelting (ESR) with consumable electrode and electroslag refining with liquid metal (ESR LM) processes. The possibility of rearrangement of the heat contributions coming from the consumable electrode and current supplying mould (non-consumable electrode, CSM) makes the core of the ESR process organisation in the CSM. The usage of liquid metal instead of consumable electrodes allows to reduce liquid bath temperature and volume in order to provide low segregation ingot. The formal assessment of physico-chemical conditions and experimental measurements of desulphurisation have shown the same level of refining ability of both processes. Replacing the classic ESR by the ESR LM is a prospective way to produce high-quality ingots from sophisticated and hard-to-deform materials, whereas manufacturing of the consumable electrodes is technically problematic and costly.     

Oxidative desulphurisation of sulphur-rich coal

Process of oxidative desulphurisation of sulphur-rich containing Ukrainian coal was carried out in the temperature range of 623-723 K by air/steam mixture in the fluidised bed reactor. Mössbauer spectroscopy was applied to study the reaction products in form of iron compounds after every step of thermal treatment. The pyritic sulphur that constitutes most of total sulphur oxidises selectively at these conditions. At lower temperature (623 K) the ferrous sulphates and pyrite oxidised mainly to the ferric sulphate. At 673 K and higher temperatures α-Fe₂O₃ and SO₂ were basic products of FeS₂ oxidation. The transformation of FeS₂ into pyrrhotite as the first stage of desulphurisation was observed at 698 K independently of the partial pressure of oxygen. The iron monosulphide (FeS) was not found at any stage of desulphurisation suggesting the pyrrhotite Fe_1−xS oxidation before the sequential FeS₂→Fe_1−xS→FeS transformation.     

Aging of passive film on UNS N08031 in a Green-Death solution

Aging of passive film formed on UNS N08031 was investigated as a function of passivation time in Green-Death solution at 40°C. The specimen surface was in a stable passive state in the solution. The passive current density increased with an increase in the passivation potential. Electrochemical impedance spectroscopy and Mott–Schottky (M–S) analyses revealed that a more defective n-type semiconductive passive film formed as the potential increased while the film became stable as the defects in the film decreased at potential lower than 1.0?V_SSE. The increase of the applied potential and the polarisation time are likely reasons for the change in passive film stability.     

About the process improvement of adsorptive desulphurisation by adding hydrogen donators as additives in liquid fuels

For the use in fuel cell system commercial fuels, like diesel or domestic heating oil, have to be desulphurised to ultra deep sulphur levels of below 1 mg kg⁻¹. To reach this goal the adsorptive desulphurisation using a nickel-based sorbent has been identified. The evaluation of the reaction mechanism reveals in principle the same route as that of the hydrodesulphurisation (HDS) whereas the sulphur is adsorbed by the sorbent instead of being converted to hydrogen sulphide. The required hydrogen for the process is provided out of the fuel itself and not by an external supply of hydrogen. This analysis leads to an easy applicable enhancement of the process by adding a hydrogen donator as an additive to the liquid fuel. In correlation to the mass fraction of the donator the reaction rates and sorbent capacities are improved significantly.Furthermore the influence of aromatic compounds has been investigated, which exhibit similar molecular structures and chemical properties than comparable high refractory sulphur species. This leads to side reactions especially of di- and tri-aromatics which influence the sulphur adsorption. A shift of the aromatic fraction from mono- to di- and tri-aromatic compounds has been observed as well as the alkylation of di- and tri-aromatics.     

湘钢铁水脱硫首期工程设计及投产

湘钢二炼钢厂铁水预处理脱硫与扒渣系统首期工程已经建成。文中简述了该项目建设概况，并小结了试车、投产期的初步效果.     

Microbial alteration of organic matter of humic coal during biological desulphurisation

The biodegrading influence of biological desulphurisation on bituminous coal and its density fractions was investigated using gas chromatography-mass spectrometry for organic matter alteration and atomic absorption for the assessment of changes in several trace element concentrations. Changes in extract group composition were assessed by comparing the contents of aliphatic, aromatic and polar compounds separated by preparative thin layer chromatography. Aliphatic compounds show extensive alteration due to biodegradation, mainly removal of n-alkanes and lighter acyclic isoprenoids from extracts. The sterane distribution was strongly affected while hopane/moretane distributions show minor changes. Aromatic hydrocarbons were less influenced but some changes were found. It can be assumed that the degree of biodegradation of density fractions increases with increasing concentration of mineral matter since density fractions with lower mineral concentration show smaller changes as a result of biodegradation than those with higher content of minerals. Reduction of concentrations of the following trace elements occurred: beryllium, chromium, zinc, gallium, cadmium, cobalt, lithium, manganese, copper, molybdenum, nickel, lead, and vanadium. The content decrease of an element is not influenced by its geochemical properties. An equally important factor seems to be bonding to organic and inorganic coal substances.