Slag Treatment Research Articles

Life cycle assessment of a PPV plant applied to an existing SUW management system

The huge amount of wastes produced by modern and developed countries involves important aspects of economical, social and technical fields and also of the environment. For this reason, different technologies have been proposed for trying to reduce the impact of waste management and disposal. Generally waste management system consists of different steps like selective collection, recycling and reuse operation, energy recovery from waste and landfilling. A new technology proposed for thermal waste treatment is the plasma pyrolysis vetrification (PPV). This system seems to have interesting perspective due to the possibility of thermal treatment of dangerous slag or waste producing inactivate vetrified substances that can be landfilled or used as building materials with no impact on the environment. In this study, the effect of the application of a PPV plant on an existing waste management system was evaluated with a life cycle assessment (LCA) analysis. All the activities connected to the existing system have been carefully analysed by collecting a large quantity of experimental data. Some assumptions have been made, in particular, on the PPV plant performance. LCA analysis results illustrate how the environmental benefits arising from the adoption of the new technology, concerns only few aspects of the whole system. Copyright © 2003 John Wiley & Sons, Ltd.

電炉スラグの粒化処理

Recently, the improvement of working environment for treating electric arc furnace slag and the expansion of uses for treated slag as the product have become an important issue in Japan. To solve these problems, OJI Steel Co., Ltd. has introduced the new slag granulating equipment developed by Nippon Steel Corporation and Hamada Heavy Industries, Ltd. which has the following features. (1) The combination of mechanical crushing in a two-stage rotating drum and quick cooling by water spraying enables to direct production of granulated slag as the product from molten slag with low energy consumption. (2) The product is small spherical particles which promise wider applications due to their physical properties. (3) Compared to the conventional slag treatment which involves slow cooling in a pit and mechanical crushing of solid slag, the working environment is improved and plant space is economized. The manufacturing technology of slag particles with mixing the oxidation slag and the reduction slag has been established by Oji Steel though operation wise improvement for stable slag granulation after its start-up in May 2000.

Concrete Aggregates Made from Sludge-Marine Clay Mixes

The large amounts of industrial sludge generated from the wastewater treatment of a copper slag recycling plant and the marine clay dredged out from excavation and tunneling works create problems of disposal. In this study, the potential use of the industrial sludge mixed with marine clay as concrete aggregate material was examined. Properties of the sintered aggregates, their performances in concrete, and their leaching characteristics were discussed. The results indicate that the incorporation of marine clay reduces the specific gravity and strength of the aggregates. The aggregates containing up to 50% by weight of clay demonstrated better aggregate impact resistance, with values ranging from 2 to 8% over the regular granite aggregates. The concrete test specimens with sludge-clay pellets as coarse aggregates yield 28-day compressive strengths ranging between 31.0 and 38.5 N/mm², which is comparable to concrete cast with regular granite aggregates. The contaminants leached from the sludge-clay aggregates were found to be below World Health Organization drinking water limits after 109 days, indicating no long-term adverse impact of leaching of the contaminants on the environment.

Prioritising objectives for waste reprocessing: a case study in secondary lead refining

Secondary lead refining produces a sulphidic slag that also contains varying quantities of lead. Initially, the objectives of this project were to treat the slag in order to recover the valuable lead as well as to render the slag environmentally benign. However, in keeping with the principles of clean technology and, specifically, the approach of clean production, the project was redefined with the following priorities: waste characterisation; waste minimisation through process improvement; waste modification; identification of slag treatment methods. Characterisation of the waste facilitated an overall process understanding and aided in identifying process deficiencies. Process improvement was aimed at reducing both the quantity of slag produced as well as the lead loss to the slag. Waste characterisation combined with local hazardous waste regulations enabled desirable waste modifications to be identified. These waste adaptations were implemented through process modification. Lastly, treatment methods for the slag were identified.

The Heating Characteristics of CaO-SiO2-FetO System Slags under Microwave Irradiation.

In order to develop an efficient heating process for the waste slag treatment, the heating behavior of the synthetic CaO-SiO 2 -Fe 1 O slag under microwave irradiation was investigated. The heating rate of the slags was found to vary with the ratio of Fe 3+ /(Fe 2+ +Fe 3+ ) in the slags and the microwave energy was most efficiently absorbed when the value of Fe 3+ /(Fe 2+ +Fe 3+ ) was around 0.16 with the largest dielectric loss of the slag. Also the heating rate was benefited considerably from the presence of CaFe 3 O 5 and magnetite phases in slags that have high value of dielectric loss. When the graphite powder was added to the slags, heating rate was drastically increased and the larger amount of carbon addition brought the higher value of heating rate.

Products of steel slags an opportunity to save natural resources

In Germany, and in the most industrial countries, the use of blast furnace and steel slags as an aggregate for civil engineering, for metallurgical use and as fertiliser has a very long tradition. Since the introduction of the basic oxygen steel making furnace (BOF) process and the electric arc furnace (EAF) process the German steel industry started extensive research on the development of fields of application for BOF and EAF slags. These investigations have been mainly performed by Forschungsgemeinschaft Eisenhüttenschlacken e. V. (FEhS), the Research Association for blast furnace and steel slags. Today steel slags are well characterised and long-term experienced materials mainly used as aggregates for road construction (e.g. asphaltic or unbound layers), as armourstones for hydraulic engineering constructions (e.g. stabilisation of shores), and as fertiliser for agriculture purposes. These multifarious fields of application could only be achieved because the steelworks influence the quality of slags by a careful selection of raw materials and a suitable process route. Furthermore, subsequent procedures like a treatment of the liquid slag, an appropriate heat treatment and a suitable processing have been developed to ensure that the quality of steel slags is always adequate for the end use. Depending on the respective field of application, the suitability of steel slags has to be proven by determining the technical properties, as well as the environmental compatibility. For this reason test methods have been developed to evaluate the technical properties especially the volume stability and the environmental behaviour. To evaluate the volume stability a suitable test (steam test) has been developed and the results from laboratory tests were compared with the behaviour of steel slags under practical conditions, e.g. in a road. To determine the environmental behaviour leaching tests have been developed. In the meanwhile most of these test methods are drafted or already accepted as a CEN standard and are used for a continuous quality control. Usually the suitability of steel slags is stated by fulfilling the requirements of national and/or international standards and regulations. Based on these standards and regulations in Germany in 1998 about 97% of the produced steel slags have been used as aggregates for road construction (e.g. as surface layer, road base and sub base for high trafficked roads), ways, earthworks, and armourstones for hydraulic structures. Consistent to the successful long-term experience not only products of steel slags but also products of blast furnace slags have been eliminated from the European Waste Catalogue and the European Shipment of Waste Regulation of the European Community, as well as from the lists of OECD for transfrontier movements by the decision of the OECD-Council from 21 September, 1995.

Characterisation and Treatment of Soda Ash Smelting Slag from the Recycling of Lead Acid Batteries

Soda ash smelting slag from recycling lead acid battery residues can result in serious environmental effects. The slag is very reactive and can cause fires through ‘overheating’ especially of large pieces of slag; it is also highly alkaline and therefore corrosive. This paper describes a systematic study of the characteristics of slag samples from a lead acid battery recycling plant, particularly the heat generation and alkalinity. Methods for the measurement of ‘reaction enthalpy with water’ (calorimetry) and soluble alkalinity (potentiometric titration) of the slag have been developed successfully, with both methods having good reproducibility. The chemical composition (XRF) and the chemical/mineralogical phases (XRD) of the slag were also obtained. Experiments suggest that the ‘overheating’ problem of slag is caused mainly by its reactions with water. A laboratory-scale treatment procedure for the slag is proposed where, through a relatively simple and safe procedure, a slag can be processed into a relatively non-hazardous form. Moreover, the waste water produced from the slag treatment can be used to neutralise the free waste acid from spent lead acid batteries to produce sodium sulphate, a useful chemical by-product.

製鋼 ダストおよびスラグ処理技術の開発（ＤＳＭの建設と操業）

製鋼 ダストおよびスラグ処理技術の開発（ＤＳＭの建設と操業）

Study on treatment of ammonia leaching slag in the metallurgical process of tungsten

The research of recovering WO3 from ammonia leaching slag in the extractive process of tungsten has been performed. The results show that the mechanically activated decomposition with Na2CO3 for ammonia leaching slag is feasible. After the treatment of ammonia leaching slag containing WO3 10%, the content of insoluble WO3 in residue is 1%–2% and the tungsten recovery is 81%–90% when the total amount of Na2CO3 and NaOH is 4 times of their theoretical value and the slag is kept for 2 hours at 190 C. The obtained Na2WO4 solution can satisfy the requirements of subsequent production process after purification.

The effect of injection parameters on slag fuming

Many slag treatment processes use injection of solid reductants into slag baths to recover metal values. In the present laboratory study, the effect of selected injection parameters such as lance diameter, gas flowrate. coal particle size and slag bath temperature have been investigated, and the behaviour of different types of reductant in slag fuming has also been considered. Coal laden gas discharge through a lance into a slag bath has been monitored by a pressure transducer. The pressure traces have revealed that the slag bath viscosity changes as fuming progresses. High momentum coal injection, a thin wall lance, intense bath agitation and increasing temperature all improve the fuming rates. Natural gas was found to be a better reductant than coal and brown coal char.

A New Approach To the Comprehensive Treatment of Waste Slag, Waste Gas and Wastewater At Sulfuric Acid Plants in China

The waste slag, waste gas and wastewater of the sulfuric acid plants seriously pollute the nearby water resources, air quality and surroundings. On the basis of the results of experimental research on making ferrous sulfate by utilizing the waste iron slag, removing sulfur dioxide from the waste gas by using an absorption solution containing ferrous sulfate and purifying the wastewater containing arsenic in high concentration by using the ferrous sulfate-neutralizing precipitation method, the research group has proposed a new method for comprehensive treatment and utilization of these three wastes in the sulfuric acid plants in China.

Growth and yield response of rice to selected amendments in an acid sulfate soil

Abstract A pot experiment was conducted in relation to the growth, yield, and nutrition of rice plants cultivated in an acid sulfate soil treated with chemical fertilizers, basic slag, lime (CaCO3), MnO2, and leaching. The soil showed a low pH (4.0–4.5: field), high ECe (0.7–1.6 S m-1) and consisted of a sulfuric horizon within the 1.2 m depth of the soil surface. Maximum growth and yield of rice cultivated in the soil were attained by the application of leaching plus basic slag treatment at the rate of 12.5 g kg-1. The other treatments also resulted in a significantly (p≤0.05) improved performance compared with the control treatment (where no amendment was applied). Leaching, basic slag, MnO2, and lime as single amendment brought about a grain yield increase of 500–900%, while leaching plus various doses of basic slag and lime resulted in an increase of grain yield of more than 1,500% over the control treatment. The highest N content of rice was obtained by the application of leaching plus basic slag (12...

New process of sewage sludge treatment and utilization of slag for construction materials : Iwai, S; Miura, Y; Kawakatsu, T Proc Symposium on Environmental Geotechnics and Problematic Soils and Rocks, Bangkok, December 1985P447–459. Publ Rotterdam: A A Balkema, 1988

New process of sewage sludge treatment and utilization of slag for construction materials : Iwai, S; Miura, Y; Kawakatsu, T Proc Symposium on Environmental Geotechnics and Problematic Soils and Rocks, Bangkok, December 1985P447–459. Publ Rotterdam: A A Balkema, 1988

4711662 Process for the simultaneous treatment of dust, sludge and steel slag : Akihisa Harada, Kitakyushu, Japan assigned to Nippon Jiryoku Senko Co Ltd

4711662 Process for the simultaneous treatment of dust, sludge and steel slag : Akihisa Harada, Kitakyushu, Japan assigned to Nippon Jiryoku Senko Co Ltd

Process for the simultaneous treatment of dust, sludge and steel slag : Akihisa Harada, Kitakyushu, Japan assigned to Nippon Jiryoku Senko Co Ltd

Process for the simultaneous treatment of dust, sludge and steel slag : Akihisa Harada, Kitakyushu, Japan assigned to Nippon Jiryoku Senko Co Ltd

Anlagen zur Sondermüllverbrennung

AbstractPlant for incineration of hazardous waste. Owing to the growth in world population and increasing industrialization, a constant rise in the production of industrial waste is to be anticipated. Thermal conversion of the pollutants leads to products which meet the requirements of “T́ Luft” (German technical regulation for air). The conditions required therefore, such as combustion temperature, excess air ratio, retention time, layout of the plant, are explained on the basis of examples. The individual components such as rotary kiln, burners, lances, container feed system, etc. are dealt with, as well as the gas cleaning, slag treatment, and heat recovery systems.

Peat ash and basic slag as substitutes for lime with reference to phosphorus uptake by turnip rape

The effect of peat ash and basic slag on the P supply to turnip rape was compared with that of calcitic and dolomitic limestone in a pot experiment performed with two acid mineral soils of pH 4.8 (CaCl2). Changes in soil properties induced by various liming agents were investigated in an analogous incubation test, and the results served to interpret the observations made in the pot experiment. When the liming materials were added in equal quantities, their ability to reduce soil acidity decreased in the sequence: calcite > dolomite > basic slag > peat ash. However, their growth-promoting effect appeared only in the second year and was not related to the neutralizing ability. In the muddy fine sand soil (3.0 % of org. C) poor in water-soluble P, the peat ash and basic slag were equally effective as calcite in increasing the dry matter yields. In the fine sand soil (6.4 % of org. C), the basic slag and dolomite significantly increased the second yield. The efficiency of peat ash and basic slag seemed to be attributable to their positive impact on P resources. In fact, peat ash served as a slowly acting P-fertilizer rather than as a liming agent. In the basic slag treatment, an increased silicate concentration obviously resulted in desorption of P. In the P-deficient muddy fine sand, the peat ash was equivalent to calcite in intensifying the P uptake. On the other hand, in the fine sand soil where the polymerization of Al due to an increased pH obviously resulted in enhanced P retention, the P uptake was higher in the soils treated with peat ash and basic slag than in those amended with conventional liming agents.

A study of the phase composition of the slag from ferrotitanium production

Today, in accordance with the plan for Soviet economic and social development, attention is being paid to the development of no-waste and low-waste technologies for the treatment of mineral raw materials and, in particular, to the problems of utilizing the waste from the metallurgical industry. From this point of view there is significant interest in the treatment of slag from ferrotitanium production whose output from the Novolipetsk Metallurgical Combine alone is many thousands of tons per year. This paper reports some results of a study of the phase composition of these slags using petrographic and x-ray phase methods with the aim of establishing possible ways of treating and utilizing these slags. The chemical composition (%) of the slags is as follows: SiO/sub 2/, 0/08-1.6; CaO, 10-17; Al/sub 2/O/sub 3/, 62-75; MgO, 1.0-3.5; FeO, 0.1-2.5; and TiO/sub 2/, 15-21. The data on the chemical composition are averaged for single types of slags from ferrotitanium production at the Aktyubinsk and Kuznets Ferro-Alloy Plants and the Novolipetsk Metallurgical Combine.

ステンレス溶鋼の還元脱りん及びスラグの処理方法

ステンレス溶鋼の還元脱りん及びスラグの処理方法

Decontamination of transuranic contaminated metals by melt refining

Melt refining of transuranic contaminated metals is a possible decontamination process with the potential advantages of producing metal for reuse and of simplifying chemical analyses. By routinely achieving the 10 nCi/g (∼0.1 ppm) level by melt refining, scrap metal can be removed from the transuranic waste category. To demonstrate the effectiveness of this melt refining process, mild steel, stainless steel, nickel, and copper were contaminated with 500 ppm (μg/g) PuO 2 and melted with various fluxes. The solidified slags and metals were analyzed for their plutonium contents, and corresponding partition ratios for plutonium were calculated. Some metals were double refined in order to study the effect of secondary slag treatment. The initial weight of the slags was also varied to investigate the effect of slag weight on the degree of plutonium removal. In general, all four metals could be decontaminated below 1 ppm (μg/g) Pu (∼100 nCi/g) by a single slag treatment. Doubling the slag weight did not improve decontamination significantly; however, double slag treatment using 5 wt.% slag did decontaminate the metals to below 0.1 ppm (μg/g) Pu (10 nCi/g).