KUCHERENKO MARIIA

      ♥ Faculty: Phisical-metallurgical

      ♥ Speciality: Ecology and Environmental protection

      ♥ Theme of master's work:

Increasing of ecological safety of converter steel production

      ♥ Scientific adviser: candidate of engineerings sciences Peristiy Michael

Materials on the theme of master's work:

Summary of research and developments

Introduction

History of converter steel production counts a few decades. In the development he passed the different stages, forcing out a martin method, difficult and nonviable methods.

A modern converter process is combination of the technology, modern facilities of technological process control and defence of environment. In combination with the aggregates of treatment out of stove this process allows to smelt steel for the production of hi-tech goods, answering the hardest requirements on a cleanness. A process possesses flexibility, the highest performance and can be in composition the most various technological chainlets.

The converter steel production as high technology will remain claimed in the nearest decades, because on modern enterprises developed and inculcated options of catching and use of outgoing gases and work of converters during utilization of converter gas as fuels characterized an economy and possibility to multiply a production became. Thus mode of taking of converter gas without dozhiganiya of monooxide of carbon With instrumental in cutting prime costs became to the improvement of ecological indexes at its smelting.

This theme is very actual abroad and especially in our country, because basic part of budgetary facilities of Ukraine is filled up exactly due to metallurgy. As is generally known, any metallurgical process leads the way formation of not only the required product but also far of liquid, hard and gaseous wastes.

To wastes of converter production non-metal resources belong except for metals: second heat-resistant materials, scorie, liquid wastes and dust, gaseous wastes. It is necessary to spare the special attention liquid wastes of converter production, which are explored less other second resources. It is besides difficult to utilize liquid wastes of converter production. Difficulties in utilization of liquid wastes arise up from the promoted maintenance in them of the coloured metals, especially zinc and lead, maintenance of which frequently exceeds in scarce zinc and leaden ores which on Ukraine practically are not present.

In my scientific researches attention is accented on the problems of the use of converter gas as the second power resource.

Scientific meaningfulness of work consists in systematization of all theoretical and practical information on the topic of preparation and use of converter gas. The analysis of the collected material and selection of the most perspective options, processes and aggregates will be made in future, and also the calculation of economic value of optimum project will be done. Some developments are taking interest enterprises, with the purpose of the practical use can take for further development and introduction on a production.

Doing the analysis of researches on this topic in works of students and teaching staff of DonNTU, it is possible to come to conclusion, that the problem of increase of ecological safety very interesting and actual. However, it should be noted that basic attention was spared development of methods of utilization of hard resources, the use of the second power resources is lighted up not in full. This fact also determines actuality and novelty of my researches and developments.

CREATION AND DEVELOPMENT OF PRODUCTION THE STEEL IN THE CONVERTER

The way of production the steel in the converter became an impulse for development of competing technologies which comprised all initial elements of the process introduced in Austria, but were too difficult from the technical point of view.

The important event which could affect the further development the way of production a steel in the converter, became occurrence of a ground purge by oxygen (process had some names — ОВМ, Q-BOP, LWS, QEK). In 1968 the problem of inflation of oxygen through the bottom dared at the expense of giving of streams of oxygen in a protective hydrocarbonic cover. The way intended for repartition the melall with the low and high maintenance of phosphorus. In 1970th with increase in capacity of converters this way progressed. Development of a ground purge became a call for the factories working on traditional technology. Introduction of the combined processes combining advantages of both methods has begun.

In 1980th ways with the combined purge became priority. Today in 85% of converters the top purge by oxygen and ground hashing by inert gas, and in 15% of converters the top and bottom purge oxygen is used [1].

1 Perfection of equipment of the converter

The initial variant of production of a steel in the converter considerably was transformed at the expense of so-called complete sets of modernisation. Hashing systems concern them inert gas, scorie removals, auxiliary nozzles and systems of prevention of emissions. At a development stage there are such control facilities technological process, as the continuous analysis of departing gases, continuous gauging of temperature of a bath and definition of its weight during a purge.

Throughout many years the problem of ablation of scorie in a ladle did not find the satisfactory decision. However high quality became impossible without its cleanliness and the low maintenance in it of phosphorus and the sulphur, scorie reached at the expense of removal. Scorie removal allows to reduce the expense of deoxidants and to reduce return of phosphorus to metal. The expense огнеупоров for ladles thanks to reduction of weight of scorie and decrease in maintenance FeO and МnО is reduced also. Now various systems of its removal are used.

Work of system of prevention of emissions of scorie is based on an ultrasonic method of an estimation of processes in the converter during a purge. Frequencies of a sound correspond with character of process of formation of scorie, in particular with formation of foamy scorie. The spectrum analysis allows to define probability of emissions and to operate them. Management is possible at the expense of moving snuffled or changes of speed of giving of oxygen.

Clearing of the top part of the converter by means of a reburning nozzle. In converters with a ground purge because of small degree of reburning the temperature of departing gases is rather insignificant. It leads to formation of outgrowths on the top part of the converter that complicates loading of a metal breakage, therefore from time to time it is necessary to make clearing of the top part of the converter. The possible decision of this problem is the special nozzle which increases degree of reburning CO in the converter and elimination of outgrowths on the top part of the converter. Besides, at use of the similar snuffled the iron expense is reduced.

Essential progress has been reached in sphere of automation of a way of production of a steel in the converter. Already in 1980th it was possible to define precisely the moment of the termination of a purge by means of the auxiliary snuffled. High reliability of results is reached at the expense of exact measurement of entrance and target parametres, and also application of advanced models of technological process.

2 Perfection of technological process

On the basis of a classical way of production of a steel in the converter a number of its variants, called to solve specific problems has been developed. We will stop on some of them.

Repartition of pig-iron with the big maintenance of phosphorus. In 1950th development of technological process has been connected with manufacture of a steel on the basis of iron with the big maintenance of phosphorus. Attempts to modernise this process were successful only partly. The problem managed to be solved only application of a way of melt of a steel in the converter. In Luxembourg and France two-level technologies into which simultaneously with oxygen in the converter blew small additives have been developed (LD-AC and OLP).

In Japan processes without scorie are actively used. After removal of phosphorus, silicon and sulphur iron is filled in in the converter basically only for carbon removal. In this case it is necessary to use the combined purge. Silicon removals allows to load into the converter less than a metal breakage, but at the existing prices for a metal breakage this way in Europe is not applied.

Increase in a share of a metal breakage. Overcoming of restrictions on weight of the metal breakage loaded into the converter, became a theme of numerous researches. The considerable quantity of attempts has been undertaken to adapt the converter for processing of materials with the raised maintenance of a metal breakage (over 30%) and even the materials consisting only from a metal breakage (100%). It was important for the enterprises lacking liquid iron. Methods of additional inflation have been developed for increase of a share of a metal breakage and the general productivity of this or that enterprise simultaneously with a purge oxygen. This working out has shown that physical and chemical properties of blown gas render a great influence on quantity of the metal breakage loaded into the converter. Nevertheless, in this sphere more perspective is use of electric furnaces.

Melt of a high-quality steel. In the aspiration expand a scope of converters metallurgists could not to ignore and steels with the high maintenance of chrome. In the late fifties and the beginning of 1960th years in this direction corresponding workings out (in Germany and Japan) were conducted.

As at the raised maintenance of carbon (more than 1%) in liquid metal probably small refinement by manufacture of a high-quality steel the converter is used as a preliminary step of processing of metal (processes KCB-S, K-BOP, KMS-S, VODK, etc.). Actually carbon removals it should be carried out at the subsequent stage at the lowered pressure СО. An example of the combined process of melt of a high-quality steel is process LD-RH-OB developed in 1970th by the Japanese scientists [2, 3].

Conclusions

It is known that the ferrous metallurgy enterprises are one of the greatest consumers electric and thermal energy in the industry. Thus the specific expense of electric energy for the last 30 years essentially has not changed.

Increase last years the prices for coal, energy carriers, water and other making manufactures was resulted by the cost price of coke and products of catching to such size above which coke manufacture becomes unprofitable, and purchase of natural fuel sharply increases the steel cost price.

As a result of industrial activity of the metallurgical enterprises the considerable quantity of the secondary power resources which caloric content fluctuates from 800 to 4000 kcal/m³ is allocated.

Physical heat and warmth of combustion of a part from them as fuel can be used with success in metallurgical cycles. In particular, for development electric and thermal energy. Use of secondary power resources can give the big economy of fuel. For the metallurgical enterprises with characteristic for them big power consumption decrease in costs on metal products manufacture will allow to raise its competitiveness in the Ukrainian and European market.

The maximum use of secondary power resources and introduction of power saving up actions solves simultaneously environmental problems at the enterprises and allows to reduce quantity of harmful emissions in atmosphere, to lower thermal pollution which is more essential at burning of gases "in a candle", than at their use in utilising coppers. Reduction of consumption of minerals combustible at the expense of use of secondary power resources will allow to lower emissions in atmosphere of toxic oxides of nitrogen, sulphur, heavy metals.

The important remark

At a writing of the given author's abstract work of the master is not finished yet. Definitive end: December, 2009 the Full text of work and materials on a theme can be received at the author or its head after the named date.

References

1. Колпаков С.В., Шахпазов Е. Х., Югов П. И. Создание и развитие кислородно-конвертерного производства в мире. [Текст] // Сталь. — 8, 2006. — С. 31 — 34
2. Алексашин А. Л., Шнальцгер Й., Холляйс Г. Создание и развитие кислородно–конвертерного производства. [Текст] // Металлург. — 1, 2007. — С. 64 — 67
3. Iron and Steel Making. http://www.stahl-online.de/english/research_and_technology/manufacturing_processes/iron_and_steel_making.asp