1070-4272/05/7811-1876C2005 Pleiades Publishing, Inc.
Russian Journal of Applied Chemistry, Vol. 78, No. 11, 2005, pp. 1876!1879. Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 11,
2005, pp. 1907!1911.
Original Russian Text Copyright C 2005 by Zarochentsev, Shvydko, Voropanova.
OF CHEMISTRY AND TECHNOLOGY
Treatment of Spent Oil-Based Cutting Fluid
V. M. Zarochentsev, A. S. Shvydko, and L. A. Voropanova
North-Caucasian Mining and Metallurgical Institute, Vladikavkaz, North Ossetia, Russia
Received June 16, 2005
Abstract-Treatment of spent oil-based cutting fluid was studied and simulated to identify the optimal
Units manufactured from very hard and wear-
resistant materials prepared from technical stone, e.g.,
agate, find wide technical application, in particular, in
instrument making. The flowsheet for manufacturing
such articles includes cutting and abrading. Virtually
all the flowsheet operations involve the use of oil-
based cutting fluids (CFs). When the radius of the par-
ticles based on SiO
is small, their gravity sedimenta-
tion is very slow. For example, in the system under
study, the time of sedimentation of the particle by
1 cm was 3 days. By taking this into account and
using the Stockes’ law for spherical particles in the
v = ÄÄÄÄÄÄÄÄÄÄ, (1)
it was possible to estimate the sedimentation rate v
at 3.858 010
. Here, v is the particle sedi-
mentation rate; r and r
, density of the particle and
medium, respectively; r, particle radius; h, viscosity
of the medium; and g, acceleration of gravity.
The known procedures for treatment of spent oils,
involving sedimentation, filtration, adsorption, treat-
ment with chemicals, distillation of the combustible,
centrifugation, pressure variation, etc., involve many
operations and are inefficient.
Earlier experiments  allowed development of a
procedure for treatment of spent oil-based CF, consist-
ing in the following. The pulp is treated with 2310%
aqueous NaOH in amount of 3317% of the pulp
volume under continuous stirring and heating to 3133
338 K, which is followed by keeping the warm mix-
ture until degradation of the colloid structure of the
gel. Next, phases are separated in accordance with
the specific weight, without heating, under intermit-
tent slow stirring of the bottom phase of the silica
residue, and the CF after sedimentation is decanted.
Technical and economic calculations showed the
promise of a change from alkali to sodium carbonate,
which enhances foaming during the pulp aeration.
Sodium carbonate is a less expensive chemical; it is
widely used in various processes and is less reactive.
The use of sodium carbonate in the process of interest
is beneficial from both economic and environmental
viewpoints and also affords a slightly greater tech-
According to the procedure proposed in , the
pulp is treated at 40370oC with an aqueous solution
containing 0.1317.7 wt % Na
in the amount cor-
responding to 3.3323.3% of the volume of the initial
oil-based CF and kept at room temperature, while the
oil phase is removed as it separates out.
The table presents the main process parameters of
the tests on treatment of the CF. The experiments
were run under the following conditions: heating over
a period of 1 h and keeping at 2933363 K for 0.53
5.0 h. The spent pulp of the CF was treated with alka-
line chemicals NaOH and Na
to remove impuri-
ties, and I-20A grade oil served as the initial CF.
Tests of the treated CF in cutting technical stone
did not reveal any departures from the ordinary run of
The experimental data were processed using the
MathCAD program . The experimental conditions
(see table) were set in the form of the x
and the degrees of recovery, in the form of the y
matrix. Block 1 of the program transforms the mat-
rices, taking account of the time of the experiment
(0.5, 1.0, 1.1, 3.0, and 5.0 h), and yields matrices
of experimental conditions X
We developed a mathematical model describing the
recovery of oil from CF as a function of a set of in-