Education of the republic of uzbekistan tashkent state technical university named after islam karimov

Table 1 (a). Chemical composition of dump slags of JSC "Almalyk MMC", in%. 
SiO
2
Fe 
Al
2
O
3
Cu 
CaO 
S 
Mg 
Mo 
Au
, g/t
Ag
, g/t
40,2 25,6 
5,82 
1,63 
1,82 
1,4 1,05 0,07 
1,4 
9,5 
Table 1 (b). Chemical composition of dump slags of JSC "Almalyk MMC", in%. 
SiO
2
Fe
2
O
3
FeO TiO
2
MnO Al
2
O
3
CaO MgO Na
2
O K
2
O 
29,8 
12,2 
41,4 0,23 
0,2 
4,17 
2,58 
1,3 
0,22 
1,43 
As can be seen from the data in Table 1, the basis of the dump slag is silicon dioxide SiO
2
and iron oxides, which together account for more than 80%. In the experiments, precisely these 
macrocomponents of the slag were initially removed to obtain the remaining valuable 
components in the remainder of the concentrate. To remove SiO
2
from the slag, ammonium 
fluoride (or bifluoride) was used [17], and iron, after removing SiO
2
, was separated by magnetic 
separation [18]. A sieve analysis of crushed slags from the copper-smelting production of the 
Almalyk MMC was carried out, the results of which are presented in Table 2. 
Table 2. Sieve analysis of crushed slag 
Class, mm 
Private 
total 
+ 20 
3,6 
10,6 
-20 +16 
7,0 
48,2 

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Chemistry and chemical technology 
27 
-16 +12 
37,0 
54,3 
-12 +10 
6,1 
72,3 
-10 +6 
18,0 
87,0 
-6 +2 
14.7 
92,2 
-2 +0.59 
5,2 
94.48 
-0,59 + 0,30 
2.28 
95,66 
-0,30+ 0.21 
1,18 
97,21 
-0.21 + 0,10 
1,55 
97,57 
- 0,10 +0.071 
0,36 
100 
- 0,071 
2,43 
total 
The experimental setup is a furnace-reactor in the form of a cylinder with a diameter of 220 mm 
and a height of 520 mm and is equipped with thermoelements for heating the samples. It has 
three compartments; in the lower part of the installation there is a test sample (slag), previously 
homogenized with ammonium fluoride or bifluoride in a stoichiometric ratio to the content of 
silicon dioxide. The two upper parts are designed to collect ammonium hexafluorosilicate (NH
4
) 
2SiF
6
, which is formed in the sublimation compartment from the sample base. The installation 
included a system of traps - condensers. The condenser for collecting (NH
4
) 2SiF
6
is equipped 
with a special baffle to prevent the (NH
4
) 2SiF
6
from falling into the starting material. The 
installation is also equipped with a system for capturing ammonia gas, which is formed during 
the reaction: 
NH
4
F + 6SiO
2 
= (NH
4
)
2
SiF
6 
+ 4NH3 + 2H
2
O
(1) 
A weighed portion of copper slag in the amount of 100 g, which passed the stage of charge 
preparation, was mixed with ammonium fluoride taken in a stoichiometric ratio with respect to 
SiO
2
and placed in the lower segment of the installation intended for sublimation sublimation of 
(NH
4
) 2SiF
6
. 
The temperature in the furnace was raised to 140 ° -150 ° C and held for 1 hour, then the 
temperature was brought to 350 ° -370 ° C and the samples were heat-treated for 1.5 hours. The 
temperature was measured with a thermocouple. After removing SiO
2
from the slag base, iron 
was separated by magnetic separation. The remainder after processing was a collective 
concentrate containing such valuable components as copper, zinc, noble and light non-ferrous 
metals. Processing of concentrates for the recovery of these metals is carried out by standard 
pyro and hydrometallurgical methods. 
For the regeneration of ammonium fluoride, the formed (NH
4
) 2SiF
6
was placed in a flask and 
dissolved in a 10% ammonia solution with a 20% excess of the required stoichiometric amount 
according to the reaction: 
(NH
4
)
2
SiF
6
+ 4NH
4
OH = 6NH
4
F + SiO
2
+ 2H
2
O. (2) 
The resulting mixture was stirred for 1 hour at room temperature, after which the precipitate was 
separated from the filtrate, washed three times and dried at 110 ° C. The result is a highly 
dispersed silicon oxide of high purity. The ammonium hexafluorosilicate wash solution had a 
blue tint, characteristic of copper compounds. Before evaporation, the solution was purified with 
a group precipitator (NH
4
)
2
S. 
Based on the data obtained, the material balance of desiliconization of the dump slag of the 
copper-smelting production was compiled, which is shown in Figure 1.

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