Research and development of technology of precious
metals’ extraction from quartzite using a closed water
cycle
N. Tyushkova
National Nano-Technological Research University (NITU), “Moscow Institute of Steel and
Alloys” Moscow, Russia.
email: cid_nofx@hotmail.com
Abstract
The results of process studies of ore showed that the most effective of the tested methods
appeared to be the direct cyanidation of crushed ore up to 95 % cl. –0,08 mm. In this
regard, the extraction of gold ranges from 91,7 % to 100 % , and silver – from 48 % to 68
% and with content of precious metals in dump cakes left the traces – 0,2 g/t on gold and
9,7-6,4 g/t on silver accordingly. A study of continuous process of countercurrent washing
out of the tails of desalinization with sedimentation of gold and silver from the discharge of
the 1-st densifier based on anion exchange resin АМ-2B allowed to make a conclusion
being very important from the point of view of the environmental protection, about an
opportunity of repeatable use of metal-free mixture in the course of desalinization and
washing out of dissolved precious metals without reduction of the technological
parameters.
Introduction
In the process of mining plants’ activity the huge amount of very small final tailings and ore
slime are being accumulated. It happens as during treatment of many types of ores all
extracted mined rock is being grinded up till the size of grains less than 0,1 mm and only
then the ore components are taken from it with assay value from 1 to 50 % for different
types of deposits. The remained 99-50 % of gangue are stored in as final tailings and
slimes, occupying thus the big ground areas and demanding substantial expenses for the
organization of the storage. Omissions and lacks of functioning of such pond tailings lead
to an intensive drift of the crushed rock by water and wind and to environmental
contamination.
Experimental Work
The subject of research appeared to be an ore sample represented with secondary
quartzites having the industrial value. As for material composition, the quartzites sample
being investigated refers to a type of gold-quartzy ore with small sulphide-content
mineralization. The main industrially valuable component is gold (2,3 g/t) and pari passu
silver (18,9 g/t). A certain value is represented by quartz as the raw material to produce
silicate walling materials, because nonmetallic minerals by 85,4% are represented with
San Luis Potosí, México
13-15 August, 2015
quartz with small content of barite. Clay minerals and sericite present with no more than
5,5% that opens an opportunity to wash out dissolved gold and silver as per a scheme of
continuous countercurrent decantation.
Results and Discussion
The analysis of obtained data shows that the ionic content of cycle water circulation in
crushing is almost no changed, excluding some accumulation of sulphates, iron,
potassium and natrium. It has to be noted that the quartzites to be processed are
characterized with relatively simple mineral content and as the obtained liquid phase as a
result of contact of water with ore is slightly mineralized. In a small amount there are
presented the ions of non-ferrous metals (lead, zinc, copper), potassium and chlorides.
From this point of view, the liquid phase to be formed as a result of processing of the goldcontaining quartzites is favorable in its use in the turns. Changes in the ionic content of
recirculation waters obtained after sedimentation of metals and used in washing out of
dissolved gold and silver are also insignificant.
Conclusions
The ionic content of the cycle water circulation is insignificantly changed and the liquid
phase obtained in processing of secondary quartzites may be used six times in the turn.
After additional extraction of silver (NITU "MISIS" know how) final tailings can be used at
manufacturing of building materials. As a result of the performed works on the process
study of the improvement tails it showed that they may be used as the main raw material
for production of silicate walling materials: silicate bricks, products of heavy and foamed
concretes, which on their mechanical-and-physical properties meet the requirements of the
existing standards.
A scope of processed ore, a study of all the factors at desalinisation of precious metals,
milling fineness of the ore, influence of the pulp density, concentration potassium cyanide
and lime as well as the kinetics of the process, allow insisting that the obtained results will
be fully reproduced at the industrial processing of quartzites of the field, but they are also
may be used for designing the mobile module unit to extract precious metals for the given
type of ores..
References
Austin and Luckie, 1972 .Estimation of non-normalized breakage distribution parameters
from batch grinding Powder Technology, 5 (5) , pp. 267–277
Austin L.G., Trimarchi, T. and Weymont, N.P.,1977 .An Analysis of some cases of NonFirst-Order Breakage Rates: Powder Technology, 17:109–113
Austin, L.G., 1982, Rate Equations for Non-Linear Breakage in Mills Due to Materials
Effects: Powder Technology, 31:127-133
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13-15 August, 2015
Austin, L.G., and Klimpel R.R., 1984a, Modeling for Scale up of Tumbling Ball Mills:
Control ´84, J.A. Herbst (eds.), p. 167-184, SME/AIME, NY
Austin, L.G., Klimpel, R.R., Luckie, P.T., 1984b, Process engineering of size reduction,
Chapter 9, Methods for Direct Experimental Determination of the Breakage Functions,
SME-AIME, New York, USA,.
NOTES:
Tables should bring their description on the top in the order of appearance, as
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Figures
Figure 1. The scheme of devices’ chain during the pilot testing of cyanidation and scheme
of the pulp’s countercurrent decantation in the thickeners’ system
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Tables
Table 1. Assay of precious metals and the main impurities in solutions of ore processing
Product name
Metals’ Assay
cobalt
copper
nickel
lead
zinc
of 1,08
6,12
14,0
<0,53
0,087
<0,001
<0,001
0,0012
First
thickener
owerflow going
0,46
on sorption
2,53
19,0
<0,38
0,003
<0,001
<0,001
0,0018
0,6
2,3
<0,12
<0,0007
<0,001
<0,005
0,0007
gold
cobalt
Mg/mL
silver
Mg/L
*
Solution
cyanidation
Degolded
solution(owerflo
w after sorption
on resin АМ-2B )
Not
detec
ted
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