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Section 17. Chemistry
Table 4 shows the density of the slurry. It can be seen that with increasing concentrations of soda solutions under the same conditions (temperature and sodium bicarbonate content) increases the slurry density.
Table 4. - Density and viscosity of suspension
H2o Na2CO3 NaHCO3 Density, g/cm 3 Comment
20 °C 40 °C 60 °C 80 °C
74 26 5 1,290 1,287 1,283 1,279 jellification
10 1,300 1,296 1,292 1,289 jellification
15 1,319 1,313 1,310 1,307 jellification
76 24 5 1,270 1,265 1,261 1,259
10 1,280 1,270 1,650 1,630 jellification
15 1,301 1,290 1,280 1,276 jellification
80 20 5 1,232 1,225 1,224 1,222
10 1,245 1,23 1,227 1,231
15 1,262 1,260 1,252 1,244
82 18 5 1,216 1,210 1,201 1,194
10 1,220 1,214 1,212 1,217
15 1,230 1,220 1,225 1,230
For example, with increasing concentrations of soda becomes thick. Thus, on the basis of the above, we can
solutions from 18 to 24%, 5% sodium bicarbonate at 20 °C, conclude that for pure trones with high output is necessary
the system density increases from 1.216 to 1.270 g/cm 3. to maintain the content of sodium bicarbonate in 18-24%
With increasing content of sodium bicarbonate and a 10% strength soda solution is not more than 15%.
solution of soda concentration of more than 20%, the system
References:
1. US patents № 7.638.109, William C. Copenhafer. 2009 - P. 23.
2. Справочник по растворимости солевых систем. Том I, М.: Гос. Хим издат. 1953 г. - 671 с.
3. Справочник по растворимости солевых систем. Том II, М.: Гос. Хим издат. 1961 г. - 2221 с.
4. Миркин Л. И. Справочник по рентгеноструктурному анализу поликристаллов. М.: Гос.издат. Физико-математической литературы, 1961. - 862 с.
5. Sibel Örgül. Evaluation of soda ash production parameters from Beypazari trona ore. Turkey, 2003. - 170 c.
Khentov Victor Yakovlevich, South-Russian State Potechnical University, Professor, Doctor of Chemical Sciences E-mail: [email protected] Hussain Hanaa Hassan, South-Russian State Potechnical University,
Graduate student Semchenko Vladimir Vladimirovich, South-Russian State Potechnical University, Associate Professor, Candidate of Science.
Copper surface etching in the donor-acceptor systems
Abstract: Etching solutions based on the donor-acceptor systems containing aprotic solvent and organic ligands — Shiff bases - have been developed to remove scale and corrosion products from copper and its alloys. To increase the rate of dimensional etching a surfactant (tetra-n-butylammonium iodide) was introduced in the ligand non-aqueous solution at concentrations exceeding the critical concentration of micelles (CMC).
Keywords: non-aqueous solvent, a surfactant, a micelle, a ligand, etching thickness.
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Copper surface etching in the donor-acceptor systems
Introduction
Etching is of dimensional etching of the surface of transition metals in donor-acceptor systems has been a process which has found wide use in various industries. Etching is often used to remove products of scale and corrosion. This is a requirement before committing a number of technological processes. At etching with sulfuric or hydrochloric acid there occurs a partial dissolution of the iron surface layers. Accumulation of divalent iron (ferrous iron) in the pickling salt solution leads to a decrease of etching rate.
Out-etching of metal and increased roughness should be considered in terms of disadvantages of this method. Sorption of hydrogen on metal at acid pickling seriously
worsen its strength characteristics. To reduce the etching rate organic inhibitors are used. Etching of copper and copper alloys is carried out in two stages. The disadvantages of etching copper should include elevated temperatures (50-80 °C) and the use of nitric acid. To exclude these shortcomings the process of dimensional etching of the surface of transition metals in donor-acceptor systems has been developed.
The experimental part
In this study, dimethylformamide which was proved in the development of technologies for the extraction of transition metals from industrial waste was used as a aprotic solvent [1, 1418-1423]. The structure of the ligands used in this study is shown in Fig. 1.
Fig. 1. The structure of the ligands used for the preparation of pickling solutions
Salitsilalanilin (CA) was successfully used earlier. The process of etching a copper plate (30x20x1 mm).was carried out in ligand solutions at temperature of 25 °C and at stirring of 600 rp-h-1. After processing in the ligand solution the samples were washed in ethanol and dried. After that they were weighed. Etching thickness calculations were performed according to the formula:
H = Am/Sd,
where Am — weight loss of the copper plate in the etching process; S — area of the plate surface; d — copper density.
The etching process was carried in air, because the
of the etching solution without with oxygen. Surfactant was introduced in the ligand non-aqueous solution at concentrations over CMC in order to increase the etching process rate. Under these conditions the micelles accumulate ligand then they are adsorbed by metal surface and destroyed afterwards. This ensures delivery of ligands in high concentrations onto the metal surface, thereby increasing the rate of donor-acceptor interaction [2, 55-56].
Result
Fig. 2 shows the etching thickness change of the copper surface as a time for dimethylformamide solution containing
Fig. 2. Dependence of the etching layer thickness h on the processing time
Ligands and the correlation coefficients R: etching rate. Table 1 shows the etching thickness change of the
1 - L2, R = 0,975; 2 - CA, R = 0,986; 3 - L1, R = 0,970 copper surface related to the time of sustaining in the etching Surfactant tetra-n-butyl ammonium iodide solution.
was introduced into the dimethylformamide to increase the
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Section 17. Chemistry
Table 1. - Changing of the etching layer thickness by10-6 cm
Etching time, min
30 60 90 120 150
without surfactant
1,79 5,39 7,19 14,30 16,10
Surfactant concentration of 0,02%
8,98 12,50 14,30 16,17 21,50
Surfactant concentration of 0,05%
3,59 10,70 16,10 19,70 28,70
Surfactant concentration of 0,10%
3,59 16,10 19,77 28,76 41,34
Surfactant concentration of 0,20%
7,19 14,30 21,50 26,90 28,70
Surfactant concentration of 0,30%
12,50 19,70 28,00 35,00 41,00
Surfactant concentration of 0,40%
12,50 19,70 26,00 34,00 41,00
The critical concentration of micelles being reached, a noticeable increase of donor-acceptor interaction rate is observed in the aprotic solvent. The high quality of the surface can be determined by measuring wetting interfacial angle of the processed surface which remains constant at different points of the copper plate surface. The etching
process proceeds at a constant rate, being testified by the linear character of dependences presented in Fig. 2.
Conclusions
The decision of dimensional copper etching of copper in donor-acceptor systems eliminating the shortcomings of traditional etching methods is provided.
References:
1. Великанова Л. Н., Семченко В. В., Хентов В. Я.//Журнал прикладной химии, 2011. - Т. 84. - № 9. - С. 1418-1423.
2. Хентов В. Я., Гасанов В. М., Карибов М. Р., Хуссейн Х. Х. Микрореакторы. Теория и практика. Махачкала: АЛЕФ, 2014. 72 с.
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