Research
of influence of a basic capacity laddle slag on its sulphidic capacity
Introduction
One of
the primary goals secondary steelmaking is the sulphur elimination of liquid metal. Effective removal of sulphur from metal was possiblly
only at enough prompting high-basicity slag that
leads to necessity of addition big mass of lime in laddle. It is accompanied by
the additional charge of the electric power and a time for sulphur
elimination conducting. For efficiency of secondary
steelmaking and decrease in its duration the minimum quantity, necessary for
reception of the set maintenance of sulphur in ready
metal. It can be possible only in the presence of adequate methods of
calculation desulphurize
abilities of steel-smelting slags of various
composition.
Substantive
provisions
For the
characteristic of desulphurize abilities of slag
usually use concept of sulphidic capacity. To define
its value it is possible from the equation for a constant of reaction of
"restoration" of sulphur from a solution:
,
,
Where - 
sulphidic capacity of slag.
The sulphidic capacity of slag varies in very wide limits at
change of composition of slag, thus to the greatest degree correlates with the
maintenance of the basic oxides in slag, to be exact with a so-called basic
capacity of slag
. For the account of other components of slag in the
literature the considerable quantity of alternatives is offered, however most
the general and formal way consists in use of concept of an optical basic
capacity:
, 
,Where - 
a basic capacity of a component of system, - 
an equivalent share of the anions which are brought in by the
given component, for example, for system CaO-Al2O3-SiO2
, 
, 
.
In the
given work the similar equation is offered for which, however, gives «integral» a dependence aspect (unlike the straight
line equation in the formula):
Where - 
an atomic fraction of a component of slag (components
elements of periodic system are considered); – 
the empirical parametres characterising each component of slag, defined from a file
of experimental data.
The conclusion
The
analysis of results has shown, that in the field of high sulphidic capacity of slags
calculation by formula gives the
overestimated value of capacity in comparison with the actual. At the same time
calculation by formula gives more adequate description of the
fact sheet. Besides, calculation by formula gives smaller value of a root-mean-square
deviation (0.25 against 0.34 by formula) at practically same quantity of
selected parametres.
Thus,
the carried out calculations allow to draw a
leading-out on preference of use of the equation for calculation of dependence of sulphidic capacity of slag from its composition. In case of
equation application it is desirable to use offered values of parametres of an optical basic capacity of components of
slag. It will allow to select more precisely necessary
composition of slag and the lime expense for achievement optimal sulphur elimination in metal.
Literature by theme
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