ХИМИЯ И ХИМИЧЕСКИЕ ТЕХНОЛОГИИ
Assistant-professor, philosophy doctor in technical
sciences Teymurova E.A., corresponding member of Azerbaijan National Academy of
Sciences, doctor in technical sciences, professor Ahmadov M.M.,
assistant-professor, philosophy doctor in technical sciences Melikova I.G.
INDIVIDUAL COMPLEX PROCESSING TECHNOLOGY OF
THE HIGH
PYRITOUS LEAD CONCENTRATES
Institute of Catalysis
and Inorganic Chemistry named after
Academician
M.Nagiyev of NAS
of Azerbaijan
E-mail:
iradam@rambler.ru
Introduction
The complex use of mineral raw material is significant reserve of
increase in material production efficiency. That has made it possible to
conserve mineral resources for the future generations and provides for
environmental protection. In lead industry the raw material are using
complexly, in the main.
To date the lead industry is one of leading branches
of the non-ferrous metallurgy. According to data of US
Geological Survey the world resources of lead exceed 2 billion tonnes [1]. Demand
for lead is constantly increasing. The method of lead blast furnace reducing
melting of the preliminarily agglomerated charge takes the predominate position
in the primary lead production technology. However, there is observed the
shortage of the lead concentrates on the modern lead world market. At the same
time, the imperfection of technological schemes of lead industry’s
metallurgical enterprises and difficulties connected with economic problems
requiring for the grate investmens are the significant factors hindering the development of lead metallurgy.
In consequence of the decrease of easily enrichable polymetallic ores
reserves there are drawn into processing the hard enrichable ores. For this
reason there are observed the increase of pyrites contents both in the ore and
the products of its enrichment. Development of lead industry provides for the
complex use of lead raw material with geological examination and drawing into
the production of a new sources – poor and hard enrichable ores.
The grate reserves of pyrites-polymetallic ores belong to Filizchay
deposite on the territory of Azerbaijan [2].
In 2007 there came into the force the agreement on the division of
production between the Azerbaijan Republic and group of the British investors
for study and prospecting with the following output of the non-ferrous and
noble metals industrial reserves of Filizchay polymetallic ores [3]. High
pyritous lead concentrates, used in our researches, have been obtained by means
of flotation of the hard enrichable high pyritous polymetallic ores of
Filizchay deposit. To present time the individual processing of high
ferriferous lead concentrates is carried out together with other lead
concentrates at the multiple pooring, that rather decreases the effiency and
complexity of the concentrates use. Elaboration and working out of rational
little-waste technology of individual processing of the high ferriferous lead concentrates promotes to drawing in
production of the new sources of raw materials - high pyritous ores and expansion of the ore base of
non-ferrous metallurgy.
In this connection rather actual is presented work, dedicated to
elaboration of the individual complex processing technology of high pyritous
lead concentrates by the method of lead blast furnace reducing melting.
Experimental part
Chemical, X-ray, microscopic, microprobe technique, polarographic,
atomic absorption and spectral analyses
methods of initial lead concentrate and products of its processing were carried
out to determine their material composition.
We have determined the following composition of Filizchay lead
concentrate, wt.%:
Pb = 40,36 ¸ 42,50; Fe = 17,55 ¸ 19,27; S(total) = 27,68 ¸ 28,39; S(sulphate) = 1,38 ¸ 1,42; Zn = 4,80 ¸ 5,44; Ag = 1100 ¸ 1200 g/t; Bi = 0,1; Cu = 1,50 ¸ 1,92; SiO2 = 1,3 ¸ 1,5; CaO = 0,01; Sb = 0,05 ¸ 0,06; Cd = 0,02 ¸ 0,04; As = 0,01 ¸ 0,05; Se = 0,009; Au - traces; Sn – from traces to
0,005; Te – traces, Tl – traces.
Characteristic features of the Filizchay lead concentrate are high content of sulphiden
sulphur in the form of pyrite and galena, and also minerals of silver and
bismuth.
The narrow and thinly mutual germination of ore minerals in the lead
concentrate as well as the small dimension of the grains and splices of galena
and pyrite with all of ore minerals of the
0,006÷0,1mm dimension are the reasons of the Filizchay ores hard
enrichability.
Agglomeration charge consist of calculated quantities of high
ferriferous sulphide lead concentrate, circulating agglomerate, and only two
fluxes – quartzite and limestone added
to the concentrate in calculated quantities in the capacity of the fluxes.
Added masses are important in determining the properties of the slag produced.
The CaO/SiO2 ratio and the total iron content appear to be most
important factors in determining the lead content in the slag.
The calculated average
composition of ferriferous slag is as follows, wt.%:
ZnO=10; FeO*=38¸42; SiO2=21; CaO=16.
On using the results of laboratory investigations we recommend for high
ferriferous sulphide lead concentrates plant processing the following average
composition of damp agglomeration
charge, wt.%:
Pb=33,8; Fe=15,10; SiO2=8,7; CaO=6,6;
S=9,3; Cu=1,08; Zn=4,16.
Agglomeration charge was pounded and granulated. Before the nodulizing
the average optimum content of the charge moisture was equal to 6.5%.
There has been elaborated the technology and carried out the nodulizing
of the high pyrite containing lead charge in large scale laboratory conditions
(in the sinter pot) by using of the air sweeping method [4]. We have obtained
the qualitative high ferriferous lead sinter, that satisfied the requirements
of its next processing by using of the lead blast furnace melting method. The
lead sinter is characterized by average porousity – 45 ÷ 47% and relatively
high solidity – 86,0÷87,0 wt.%.
The average chemical composition of the obtained
lead sinter is as follows, wt. %: Pb=36,4;
Fe=16,3; Zn=4,3; Cu=1,1; Ag=1200 g/t, Bi=0,11; SiO2=10,65;
CaO=5.2 S(total) = 3,2; S(sulphiden) =1,4.
In consequence of the high content of sulphiden sulphur in the form of
pyrite the processing of the lead agglomeration charge, promotes to obtaining
of the rich sulphuric dioxide containing burning gases (>7÷10%), used for sulphuric acid production.
Silver and bismuth containing phases are concentrated, on the whole, in
the lead minerals of agglomerate.
There have been established
the following distribution of the lead forms in the lead sinter, wt.%: Pb(total)=34,0÷38,8;
Pb(oxidic) =2,30÷2,30; Pb(metallic)
=1,5÷1,8; Pb(silicate) = 20,10 ÷ 22.50; Pb(ferritic)=7,0÷7,8;
Pb(sulphiden) = 3,1÷3,8.
The reducing melting of the
obtained high ferriferous lead sinter
has been carried out in laboratory conditions by use of conversed natural gas
[5] or mixture of natural gas and water vapors as a reducer [6]. Active
conversion of natural gas in mix with water vapors takes place at the
high reducing melting temperature (1100÷12000C). Slags, obtained under optimum conditions of
reducing melting of high ferriferous lead sinter with use as a
reducer of conversed natural gas and mixture of
natural gas and water vapour have analogous substantial composition
(Table).
The higher containig of the easily reduced ferritic
lead (7,0÷7,8%) composition in lead sinter promotes to increasing of the
lead extraction into the lead bullion in optimum conditions of reducing meltig.
The lead bullion is collector of silver and
bismuth. That is why reduced to metal silver and bismuth are concentrated into
the lead bullion at the lead reducing melting process. Their extraction into
the lead bullion increases too.
Possibility of the effective processing of
Filizchay lead concentrates according to proposed technology has been confirmed
by the results of industrial trials of high ferriferrous sulphide lead
concentrates processing by lead blast furnace reducing melting at Chimkent Lead
Plant (now Shimkent Lead Plant, Kazakh Republic) [5].
Typical assays composition of the high ferriferous lead sinter obtained
at Chimkent Lead Plant (ChLP) is as
follows, wt.%: Pb=36,1÷42,0; S(total)=2,05÷3,27; S(sulphiden)
= 0,78÷1,27; Cu=2,0÷2,8; Fe=17,3; Zn=6,0: SiO2=10,0÷12,0;
CaO=6,5÷7,5.
The data of the trials series of high
ferriferous lead sinter´s
reducing melting with the operating blast furnace have indicated, that in
optimum conditions low lead losses with the slag (1,4¸1,8 wt.%.) and its high extraction into the lead
bullion can be achieved with good
performance: the moderate sinter throughput – 55¸60 tonnes/m2·day, with a ratio CaO/SiO2=0.70–0.74
and FeO concentration in the slag in the ranges of 38.4¸41.0 wt.% (Table). The concentrations of CaO and SiO2
in the lead sinter are above of 6.5–7.5 and 10.0¸12.0 wt.% respectively.
Table. Optimum slags compositions of the high ferriferous lead sinter reducing
meltings
|
Slags |
Pb, wt.% |
ZnO, wt.% |
FeO, wt.% |
CaO, wt.% |
SiO2, wt.% |
CaO/SiO2 |
|
1 |
1.4÷1.8 |
10.6÷12.0 |
38.4÷41.0 |
14.2÷15.0 |
20.4÷24.1 |
0.70÷0.74 |
|
2 |
1.67÷1.78 |
10.02÷10.70 |
37.7÷40.5 |
15.56÷16.47 |
19.7÷21.3 |
0.79÷0.84 |
|
3 |
1.1÷1.3 |
9.9÷10.15 |
37.7÷40.5 |
15.56÷16.47 |
19.7÷21.2 |
0.75÷0.84 |
1– slags of
ChLP; 2 – slags of laboratory investigations with use of conversed natural gas as a reducer; 3 –
slags of laboratory investigations with use of mixture of natural gas and water vapors as a reducer.
The liquids temperature is estimated to be ~11700C for plant´s slags and
~11900C for slags of laboratory
investigations.
The choice of natural gas conversion method must be determined by
peculiarities of the processing technology and economical consideration at the
industrial installation of proposed
technology with use of conversed natural gas or mixture of natural gas and
water vapors as a reducer.
Conclusions
The technology of the individual complex processing of high ferriferous
shulphide lead concentrates by the way of the blast furnace reducing melting is
developed.
The series of trials with
the operating blast furnace within two years period was confirmed the results
of proposed technology.
The high technology
performance characteristics of complex processing of high ferriferous lead
sinter at operating blast furnace(ChLP) and similarity of compositions of
agglomeration charges and sinters, obtained in laboratory conditions and also
at operating trials of lead blast furnace melting at ChLP have testified to the
possibility of high effective plant processing
of Filizchay high pyrite containing lead concentrates working out at the
plant with use of the results of our large-scale laboratory investigations.
Scientifically
substantiated, advanced and calculated optimum composition of the high pyritous leaden agglomeration charge
have been installated into the industrial production.
The individual complex processing of the high ferriferous sulphide lead
concentrates by the way of lead blast furnace reducing melting is of a great
economic importance. The obtained data testify to that using Filizchay lead
concentrate in exchange for pyrite, added to agglomeration charge, will provide
with getting “rich” SO2-containing burning gases, an increase of
lead, silver and bismuth extraction into the lead bullion, and the low content
of the lead in slag, an output of additional volume of commodity product at the
expense of high composition of noble metals and bismuth.
The results of carried out investigations may be used
as the basis of processing technology of other high pyritous polymetallic ore
deposits of analogous to Filizchay ore deposit, such as Ozernoye,
Kholodninskoye(Russia), Jayrem(Kazakhstan), Rammelsberg, Meggen(Germany),
Maunt-Isa (Australia), as well for the improvement and intensification of plant
technology of lead concentrates processing.
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Teymurova Emma Abasovna – assistant-professor,
philosophy doctor in technical sciences, leading researcher of Institute of
Catalysis and Inorganic Chemistry named after Academician M.Nagiyev of Azerbaijan National Academy of Sciences;
Ahmadov Mubariz Medjid – corresponding member of
Azerbaijan National Academy of Sciences, doctor in technical sciences,
professor, head of department of Institute of Catalysis and Inorganic Chemistry
named after Academician M.Nagiyev of Azerbaijan National Academy of Sciences;
Melikova Irada Gasan – assistant-professor, philosophy doctor in technical
sciences, leading researcher of Institute of Catalysis and Inorganic Chemistry named
after Academician M.Nagiyev of Azerbaijan National Academy of Sciences.