STUDY OF AN ELECTRIC FURNACE PHYSICAL MODEL
FOR FIRING VERMICULITE WITH A “ZERO” MODULE
A. I. Nizhegorodov
and A. V. Zvezdin
Translated from Novye Ogneupory, No. 6, pp. 13 – 18, June, 2016.
Original article submitted March 16, 2016.
Results are considered for experimental research carried out in a test furnace for checking the possibility of
completing heat assimilation by vermiculite grains and structure formation within them due to transfer of ver
miculite exergy into mechanical transformation energy in a so-called “zero” module with reduced energy re
quirement. A relationship is established by experiment for vermiculite product density at the inlet to the “zero”
module and at the outlet from it on temperature of the heater surfaces in the furnace electric modules. Time is
determined for passage of a vermiculite grain through the “zero” module, and a value of complete heat assimi
lation factor is established correcting the analytical model of the process. An analytical expression is provided
describing vermiculite heat assimilation taking account of the correcting completeness factor. It is shown that
use of a “zero” module may reduce the energy requirement and firing power requirement by 10 – 20% in rela-
tion to “zero” module installation location.
Keywords: expanded product, electric furnace, heat assimilation, exergy, firing module, “zero” module,
Results have been given in an article  for a study of
analytical models of vermiculite heat assimilation and ther
mal conductivity of its grains taking account of completion
of structure formation in an additional nonelectric “zero”
module. On the example of vermiculite concentrate KVK-4
of the Kovdorsk deposit a coefficient was determined for
completeness of heat assimilation and time of temperature
equalization, equal to the additional time of vermiculite
within a furnace “zero” module. Theoretically the problem
was resolved of reducing the power requirement for firing
due to saving electrical energy with a reduction in furnace
power and a firing regime with reduced temperatures.
The new technical solution using a nonelectric or
so-called “zero” module installed successively in a chain of
standard electric modules , makes it possible to utilize
thermal exergy accumulated by vermiculite and radiated heat
from fine vermiculite factions and inert material for complet
ing vermiculite mechanical transformation (structure forma-
tion) in the absence of an external heat source.
FURNACE UNIT WITH A NONLETCRIC
An electric furnace is shown in Fig. 1 with an additional
module fitted with a system for inert material separation after
firing, present within vermiculite concentrate. The furnace
contains a dispenser 1, chute 2, and body 3 in which at an an
gle to each other electric modules 4 are arranged with a ther
mal energy recuperator 5 connected with pipelines 6, insu
lated with heat-resistant material (it is shown by thin lines).
An additional nonelectric module with a collector 7, heating
chambers 8, and firing space 9 is located beneath the lower
electric module 4 and fitted a pipeline 10 connecting it with
an extractor fan. At the lower end of the “zero” module there
is heat screen 11 connected with an outlet pipe 12 of the ex
traction fan. The furnace is equipped with a bunker 13 for ex
panded vermiculite and a bunker 14 for inert material and
also a fan 15.
A drum dispenser feeds concentrate into the upper mod
ule 4, pouring from one module to another the concentrate
subjected to action of heat radiation from electric heaters and
Refractories and Industrial Ceramics Vol. 57, No. 3, September, 2016
1083-4877/16/05703-0246 © 2016 Springer Science+Business Media New York
FGBOU VO Irkutsk National Research Technical Institute
(IRNITU), Irkutsk, Russia.