The working parameters of the slips are as follows: Fineness of milling (Lisenko method), I0 ml ........ 7-8 Bulk density, g/cm" ................................ 1.71-1.73 Covering capacity (cylinder method), g/dm 2 .......... 5-6 In these compositions an increase in the MnO concentration leads to an expansion in the firing range (due to the reduction of its lower temperature limit) and an increase in the flowability of the coating. Moreover, replacing the sand by KR causes an increase in the alkali resistance of the coating. Replacing the SiO2 by Zr02 leads to a similar effect. Using KR for synthesizing enamels leads to a reduction in the content of scarce clay from 5 to 2.5% because of the capacity of the particles of manganese-containing frit to form a suspension. The chemical compositions and the properties of the newly developed fluorine-free protective coatings are shown in Tables 1 and 2. From Table 2 it is clear that the properties of the acid- and alkali-resistant enamels made with the Chiatursk carbonate ores, containing small amounts of manganese, correspond to the requirements of OST 26-01-1-79 specified for coatings applied to chemical apparatus of the first class. Compared with regular production enamels, these enamels are characterized by a reduced firing temperature (760-860~ a wider range for coating formation (80-100~ and the necessary thermal coefficient of expansion values (103.3-107.0) • i0-" ~ Moreover, they are economical and use less material since the batches are compiled from 5-6 components. The MES-I, MES-2-1 and MES-3 enamels have passed industrial testing at the Poltav enamel machine production association. The proposed savings from their use at the Poltavsk Khimmmsh factory is 85,000 rubles a year.
~SE OF SOLUTIONS FROM THE WET-CLEANING OF FLUE GAS OF A GLASS MELTING FURNACE V. A. Vavilov, V. T. Chernetskii, A. A. Tsymbal, A. M. Petrova, and T. M. Nechaeva
UDC 666.004.8:662.613.5:666.826
In order to clean the flue gas from lead-containing dust, several glass plants now commonly use the method of wet cleaning using the foam apparatus designed by the Scientific Research and Planning Institute of Technical Cleaning, which works in a sprinkling regime [i]. The used solutions formed during the gas purification contain significant amounts of water-soluble lead salts and require special reagent purification. Characteristics of the SolUtions from Wet Gas Cleaning of a Glass-Melting Furnace with a Productivity of i0 ton/day Volume of waste liquid m'/h ................ Temperature, ~ ............................ pH ........................................ Concentration of components, mg/liter: Na+ ....................................... K + ....................................... Pb 2+ .....................................
2.5 60 8.1 24 224 i0
The Institute and the Kiev Artistic Glass Plant have studied the possibilities of replacing water by these solutions at 50-60~ to wash crystal ware after acid treatment. Scientific Research and Planning Institutes of Technical Cleaning; Kiev Artistic Glass Plant. Translated from Steklo i Keramika, No. 8, p. 7, August, 1987.
0361-7610/87/0708-0325512.50
9 1988 Plenum Publishing Corporation
325
TABLE. i Parameters of washing water at 50~ current variant
Test
new variant
coneen-
trati~
pH | o f Pb~ , , Img/liter
pH
concentration
of Pb2+' m~/liter
I
1
2,50 ]
3
2.54
2
2,45 I
Average2
value t
7,5
3,7
8.4
2.8
s,o
2.9
56+ J
3,45•
2,12
5,20
6.12
4,~•
*Average values were obtained by the statistical treatment of a variation series with a confidence level P -- 0.95.
~
\
~
O Process water
~
O
"7
. ,F
cleaninE 5
TO neutralization\y/ Fig. i. Production system for the wet gas-cleaning plant. The proposedproduction system for using the used solutions for the preliminary washing of glassware is shown in Fig. i. According to this system the dusty gas is passed from the flue of the glass-melting furnace to the gas-cleaning apparatus (I) where it is given a twostage treatment in a high-turbulence foam layer of the washing liquid formed on the gas-distribution grids of collapsible and immersion types. The cleaned gas is dispersed in the atmosphere and the used solution at a temperature of 50-60~ arrives at the special settling tank (2). After the solid impurities have been separated, the solution from the settling tank is fed to the storage tank from which it goes via the nozzle (3) to the washing bath (4) of the equipment for the chemical washing of the crystal. It then goes from the washing baths to the averaging sumps (5) where the acid effluent water is diluted and then to the neutralization stage. This process has been used in the No. i High-Quality Hollowware shop at the Kiev Artistic Glass Plant. Plant tests on the system were carried out during the normal working regime of the glassmelting furnaces and chemical-polishing equipment. The tests were intended for comparing the washing parameters of the glassware using the current process with those of the proposed process. The quality of the washing of the glassware was also evaluated. Table i gives the comparative data for the washing of glassware using the current and new variants. For such fundamental parameters as the volume and temperature of the washing liquid, values were achieved which correspond to process specifications. Moreover, there was a slight reduction in the concentration of water-soluble PB 2+ in the treated liquid due to the increased value of pH of the solution reaching the glass-washing from the wet gascleaning equipment. This can be explained by the fact that at a pH > 7 the washing solution contains, in addition to the carbonates, hydroxyl ions which form the insoluble basic salt
326
Pbz(OH)2C03 [2, 3] which reduces the consumption of lime in the neutralization process. An expert evaluation of the quality of the glassware over a period of 20 days showed that it would be possible to make use of the used solutions for washing crystal ware. In this case the good quality of the articles produced was not degraded. Moreover, annual savings in heat energy from the utilization of the heat from the flue gas of the glass furnace in an amount of 7913 GJ (1890 Gcal) were achieved for an annual output of 2152 tons of articles. The saving resulting from the introduction of this technological system at the Kiev Artistic Glass Plant was 30,000 rubles per year. LITERATURE CITED !.
2. 3.
A. N. Balabolkin, V. A. Vavilov, and A. A. Tsymbal, "A method of cleaning flue gas from a gas-flame crystal furnace," in: Proceedings of the Scientific Research and Planning Institute of Technical Cleaning [in Russian], No. 20 (1980), pp. 55-60. L. B. Milovanov, "Cleaning and the use of waste water from ferrous metal enterprises," [in Russian], Metallurgiya, Moscow (1971)o V. G. Solonetskii, T. I. Petrashina, and L. P. Kostyuchenko, "The dependence of the concentration of lead in neutralized waste water on the value of the pHi" in: Proceedings of the Scientific-Research Institute of Technical Cleaning [in Russian], No. 18(1979), pp. 87-90.
327
