Team Number : E41

ANALYSIS OF GANGUE MINERAL ON DEPOSITS METAL TOWARDS

INDUSTRIAL MINERAL AND MATERIAL PROCESSING

Imam Fuad Wahyudianto

Chemistry Department, Universitas Gadjah Mada, Yogyakarta, Indonesia.

Sekip Utara BLS 21, Yogyakarta 55281, Telp. ( 0274 ) 545188 Fax. ( 0274 ) 545188

Email : Imamfuad@rocketmail.com

ABSTRACT

Gangue minerals have many effect in ore metals and mining, the examples is in

kaolin and kuarsa in Bangka Belitung, effect in separation ore nickel and hydrophobic at

recovery gold using ores obtained from the active small scale gold mining sites in

southeast asia.The effects of silica gangue and high sulphide gangue on gold attachment

were examined including the effect of surface activators (potassium amyl xanthate) and

the possibility of depressing the effects of gangue using reagents. The results of

separation nickel showed an overall upgrade of Ni from 0.4 to 0.7% Ni in the flotation

feed sample, at a recovery of 87% and from recovery gold showed there was no change in

gold recoveries when the amount of oxide gangue (quartz) in the ore was increased,

indicating absence of competition between gold and quartz gangue. High sulphide

contents in the ore above 6% reduced gold recoveries considerably.

ESSAY

Some usefull metal usually banded on ore mineral together with the others

chemical elements. This mineral usually spreaded in rock and soil consists of framer

mineral rock that little contains metals. Usually this mineral mineral non metals called as

gangue. The alloy of ore mineral and mineral gangue will become ore mineral. Some of

ore mineral have shine metal like kalkopirit, cuprit, and also there were have not shine

metals like malakhit, bauksit, sfalerit, and usually combine with other element such as

Al, Si, S, O . Because of that people can take 1 element from kind mineral the example

copper can taken from mineral kalkopirit, malakhit, cuprit and azurit.

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Ore Mineral can aslo classified be primer mineral ( hipogene ) defined as mineral

formed together with others mineral and not yet weathering and secunder mineral

( supergene ) defined as mineral from the results of weathering on rock

Gangue mineral is part of association mineral that forming rock and doesn’t ore

mineral on trapped rock. This showed kind of original mineral gangue :

Kind Name

Compositio

n Hipogene Supergene

Oxide Oxide SiO2 X X

  Others silica SiO2 X X

  Baucsit Al2O3.2H2O - X

Carbonat Kalsit CaCO3 X X

  Dolomit CaMgCO3 X X

  Siderit FeCO3 X X

  Rodokhrosit MnCO3 X -

Sulphat Barit BaSO4 X -

  Gips CaSO42H2O - X

Silicate Felspar * X -

  Garnet * X -

  Rodonit MnSiO3 X -

  Chlorit * X -

  Mineral Clay * X X

Others Rock * X X

  Fluorit CaF2 X -

  Apatit

CaF( CaP

O4)3 X -

  Pirit FeS2 X X

  Markasit FeS2 X X

  Pyrrhortit Fe1-xS X -

  Arsenophirit FeAsS X -

Note :*Complex Composition or easy to change x available

As produsen of metals, that mineral is useless but for other necessity will have

specific value, the example in mining lead ore in Bangka Belitung that mineral gangue in

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form kaolin and kuarsa. Ore mineral in that table can be called as the mixture of ore

mineral and mineral gangue that can be mined and profit. The example is pirit contains

Au can’t called as ore mineral because that precentage is slow and the cost is very

expensive to release the gold. Although high precentage gold, but cost of mining and

separating that gold is not balanced with disposal cost, mineral pirit can not be callled as

ore.

The Development of technology maybe will change the status from not ore be

ore. The example of gangue ore mineral before world war II spodumen is costless but

with the improvement of technology of rcoket, spodumen is usefull because that mineral

can be used for porcelain resistance with high temperature. The collection of mineral that

mined as ore depends on mineral gangue or the others mineral although on a few number,

because they have possibility can be used, the example is ore timbel, lead or copper be

valueless because contains of bismuth ( Bi), Arsen ( As ), or cadmium. Bi, As, Cd

although in a few amount is very hard to separated.

Gangue Minerals very usefull to industrial mineral and material processing one

the example in Separation of low grade nickel ore. Density separation is widely used to

pre-concentrate ore minerals and reject unwanted gangue prior to the main processing

stage of an ore (e.g. flotation). For base metal sulfide ores, dense medium separation

(DMS) is used to separate the sulfide minerals, which are relatively dense, from the less

dense silicate gangue minerals. With pre-concentration it is possible to reject a large

portion of the run-of-mine (ROM) mass, with a metal grade that is equal to or less than

the tailings grade that would have been achieved by the main processing stage, in this

case, flotation (Creswell, 2001).

The consequent metal upgrade of the feed can result in the exploitation of

deposits previously considered to be uneconomic. The Tati Nickel Mine in Southeast

Asia is an example of where Ni ore is successfully pre-concentrated using DMS before

being fed into a flotation plant. Other benefits include the energy and cost savings due to

the reduction of silicate gangue fed to the milling and flotation plant, as well as the

improved feed grades that potentially result in improved metal recovery and concentrate

grade. A reduction in the amount of silicate gangue introduced into the circuit will also

lower the reagent costs associated with depressant addition (Creswell, 2001).

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Results:Dense Medium Separation

A summary of the DMS results is given in Table 1. The mass recovery to the sinks was

48% at a density cut point of 3.0 g/cm3, which is in agreement with preliminary HLS

testwork conducted on the feed sample. The Ni was upgraded from 0.39% to 0.67% at a

recovery of 83%. No significant Cu upgrade was achieved.

Table Summary of DMS testwork at a cut point of 3.0 g/cm

The Ni grades and recoveries, as well as mass distribution of the bulk sample, were

calculated. for different streams of the flowsheet, from the ROM material to the

calculated flotation feed sample. The data have been mass-balanced with variability in the

measured and smoothed grades less than 5%.

Overall the Ni showed a 54% upgrade from 0.4% in the ROM to 0.7% in the flotation

feed, with an 87% Ni recovery to the flotation plant. Approximately 44% of the ROM

mass was rejected in the DMC overflow, with the Ni grade of the overflow at 0.1%.

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Flowsheet for the testwork showing different streams

Beside the effect on gangue mineral in separation nickel ore, there were also the

effect on gangue minerals in hydrophobic at recovery gold. using ores obtained from the

active small scale gold mining sites in southeast asia. Gold ores of different gangue

contents were tested. The effects of silica gangue and high sulphide gangue on gold

attachment were examined including the effect of surface activators (potassium amyl

xanthate) and the possibility of depressing the effects of gangue using reagents. The

presence of gangue minerals in gold ores is among the main reasons for the selection of

appropriate gold recovery method. The common gangue minerals which are normally

associated with gold ores include quartz, fluorite, calcite, pyrites, chalcopyrites, galena

and many others in small amounts e.g. arsenopyrites, fluorites, carbonates and chlorites

The hydrophobic recovery of gold is dependent on greater oleophilicity and

hydrophobicity of gold com- pared to many other minerals. However it is known that

some of the gangue minerals that are associated with gold have oleophilic and

hydrophobic properties and the presence of such mineral gangue in the ore may be a

source of competition during the attachment to agglom- erates. Such minerals include

mainly the metallic sul- phides gangue. The presence of low amounts of sulphides in the

ore up to 5% chalcopyrite is reported to have little effect on gold recoveries.

This work is focused on the effects of high sulphides and other gangue on gold

recoveries using the hydropho- bic recovery of gold. Potassium amyl xanthate was the

reagent used as surface activator in the tests. This work was done as a contribution to the

ongoing research on the application of the hydrophobic recovery of gold as an alternative

to the hazardous use of mercury in small scale gold mining

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The results were evaluated in terms of gold recovery, volumes and grade of

concentrates formed. There was no change in gold recoveries when the amount of oxide

gangue (quartz) in the ore was increased, indicating absence of competition between gold

and quartz gangue. High sulphide contents in the ore above 6% reduced gold recoveries

considerably. It was noted that potassium amyl xanthate surfactants increased the

attachment of both gold and the sulphide gangue. Using lime at pH 10 it was possible to

depress the sulphide gangue which is mainly pyrite and hence increased gold recoveries

considerably

Concentrate weights attained due to gangue recovery (with surfactant).

There was no change in gold recoveries when the amount of quartz gangue in the

ore was increased, suggesting the existence of quartz particle hydrophilicity due to

reaction between the polar surface and the water dipoles.

References :

B. A. Wills and N. M. Tim, “Mineral Processing Technology; An Introduction to the

Practical Aspects of Ore Treatment and Mineral Recovery,” 7th Edition, Elsevier Science

& Technology Books, 2006, p. 269.

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Cresswell, G.M., 2001 Pre-concentration of base metal ores by dense medium separation.

SAIMM Copper, Cobalt, Nickel and Zinc Recovery Conference, 10 pp.

J. P. Calvez, M. J. Kim, P. L. Wong and T. Tran, “Use of Coal-Oil Agglomerates For

Particulate Gold Recovery,” Minerals Engineering, Vol. 11, No. 9, 1998, pp. 803-812.

Sukandarrumidi, 2007, Geologi Mineral Logam explorer muda, Gadjah Mada University

Press, Yogyakarta, p. 3-20.

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