Mindanao State University – Iligan Institute of Technology College of Engineering Department of Ceramics, Metallurgical and Mining Engineering
Flotation John Logos N. Guiang, Guiang, Junnile L. Romero, Romero, LovelleRhoy C. Manpatilan, Juvan G. Navidad, Kristine Mae M. Pazo, Franes Liane C. Matildo , Nino !onn ". #nino M$%$ &'() M*N$R#L PR+C$*NG L#!+R#%+R-
#!%R#C% Flotation after eing studied, has een performed in the laoratory using Denver Flotation Cell! The students "ere ale to operate the said process and "ere ale t o recover concentrates! #uantities in creating pulp at a certain percent solids "ere also calculated! Factors affecting flotation such as flotation time, feed si$e, p%, pulp density, conditioning time and reagents dosages "ere also revie"ed! Keywords Keywords&& Flotation' Collector' Froth
&. *N%R+/C%*+N Flotat Flotation ion is a physic physico(c o(chem hemica icall separa separatio tion n process that utili$es the difference in surface properties of the valuale minerals and the un"anted un"anted gangue gangue minerals minerals )*ills, )*ills, +-, p!+-./! p!+-./! There are three mechanisms that a material eing recovered y flotation from the pulp undergoes! )0/ The selective attachment of valuale minerals to air ules or 1true flotation2 is the most important mechanism and represents the ma3ority of particles that are recovered to the concentrate! The other t"o mechanisms are )+/ entrainment in the "ater "hich passes through the froth and )4/ physical entrapment et"een particles in the froth attached to air air u ule less or aggr aggreg egat atio ion! n! The The degr degree ee of entrainment and physical entrapment also controls the separa separatio tion n effic efficien iency cy et"e et"een en the valua valuale le mineral and gangue! In the flotation process, ore is ground to a si$e sufficien sufficientt to ade5uately ade5uately lierate lierate desired desired minerals minerals from "aste roc6 or gangue! It is conditioned as slur slurry ry usin using g spec specif ific ic reag reagen ents ts refe referr rred ed to as 7colle 7collecto ctors rs88 "hich "hich are organ organic ic compou compounds nds that that adsor to the surfaces of the desired minerals! They form form a monolay monolayer er on the partic particle le surfac surfacee that that esse essent ntia iall lly y ma6e ma6ess a thin thin film film of non( non(po pola lar r hydrophoic hydrocarons! The collectors greatly increa increase se the contac contactt angle angle so that that ule uless "ill "ill adhere to the surface! The greater the contact angle, the greater is the "or6 of adhesion et"een particle and ule and the more resilient the system is to disruptive disruptive forces! The particle particle and ule must remain attached "hile they move up into the froth
layer at the top of the cell! 9nce at the top, the froth layer must persist long enough to either flo" over the discharge lip of the cell or to e removed y mecha chanica nicall froth oth scr scraper aperss! If the the froth oth is insuffic insufficiently iently stale, the ules ules "ill rea6 and drop the hydrophoic particles ac6 into the slurry prematurely! prematurely! To remedy this, another reagent, the frothers are added to staili$e air ules so that they "ill remain "ell(dispersed in the slurry and "ill form a stale mineral(loaded froth layer that can e scraped off efore the ules urst! The rema remain inin ing g unfl unfloa oate ted d miner ineral al slur slurry ry "ill "ill e discharged as tailings! This is usually applied for the concentration of metallic sulfide minerals such as copper sulfides, lead lead sulf sulfid ides es,, etc! etc! at pres presen ent' t' ho"e ho"eve verr, it has has ecome highly effective in the treatment of a great variety of o:ide ores, native ores, and even non( metallic minerals! 0!0 93ective This e:pe :periment mainly aims to familiari$e the student "ith the concentration of minerals minerals using froth froth flotation! flotation! Specifica Specifically lly,, this study study aims aims to deter determi mine ne ho" ho" fact factor orss such such as flot flotat atio ion n time time,, feed feed si$e si$e,, p%, p%, pulp pulp dens densit ity y, conditionin conditioning g time and reagent reagent dosages dosages control the "ettaility of minerals and conse5uently, its aility to float!! 0!+ Significance of the Study In ;hilippines, numerous mining and mineral processing such as 9ceana
Leaniel C. Silva, Instructor. ;age & of 0 Flotation ! Submitted to Engr. Leaniel
in concentration of valuale metals! >no"ledge and familiari$ation of flotation process and techni5ues are given important consideration for the enefit of the students!
'. M$%"++L+G+!0 Materials The materials and e5uipment used in this e:periment "ere Denver Flotation Cell, 0 m? graduated cylinder, 0 m? graduated cylinder, 0 m? syringe, @ASF=9T% 40, @ASC9? 4B)SE/, "ash ottle, analytical alance, and Aluminum pan! +!+ E:perimental ;rocedure Sample ;reparation& The particle si$e analysis of the "hole sample "as otained using Sieve =otary Sha6er! After"ards, the sample ore "as made into a pulp of 0 solids y "eight! Conditioning ;eriod The pulp "as then poured into a 0 m? flotation cell then a !B grams of @ASC9? 4B)SE/ collector "as added! ?ime "as added in order to maintain the al6alinity of the pulp! For the first trial, the p% "as raised from to B!4 upon the addition of lime! For the second trial instead of using ?ime, the performer use Feldspar due to lac6 of supply! The pulp "as agitated "ithout aeration at ma:imum rpm for aout 0 minutes in the first trial and 0B! minutes in the second! Flotation ;roper After the conditioning period si: )-/ drops of frother through the syringe "as added to each trial, and "as appro:imated to e !- m?! After"ards, the pulp is su3ected to agitation at ma:imum rpm and "ith aeration! The initial recovery of concentrate "as that, the system "as su3ected to agitation and aeration "ithout scraping the floated material until such time "here scraping is necessary! The scraping period "as done every minute! Every scraping period is consisting of 0 scrapes and due to losses of "ater there is a need for additional "ater in order for the float to reach the e:it of the cell "hich called 1hutch "ater2 and the amount of hutch "ater use "as 0.- m?! The flotation time "as minutes per trial! The concentrate and tailings "as decanted and dried and measured its specific gravity in order to confirm the results!
PSPC auae rl t i c l CFmC l oo o p n eADpl l a S i z e ntlc e a ed t ni AntPP a rr n a l y s titP o ir r o ane t iaGee s pp ( O r e nPep ria n r Slaa trra m p l goAa ptn i a eyhaa )tte ii Pelo y enr s r i i srooo i nndn sig s Figure &. ;rocess Flo" Chart for Gond *or6 Inde:!
1. R $/L%
#N *C/*+N
4!0 Specific
Mass empty pycno )M0/ Mass pycno H ore )M+/ Mass pycnomenter H "ater H ore )M4/ Mass pycnomenter H "ater )MB/ Specific gravity )
0! 4!. 4!.0 B! '.12
The tale sho"s the ore density "hich is +!4Bgm?! This density is essential for the calculation of the amount of solids and "ater needed in reaching a specific pulp density and percent solid! 4!+ ;ulp Composition ;ulp density at 0 solids is calculated using the formula&
Flotation ! Submitted to Engr. Leaniel C. Silva, Instructor. ;age ' of 0
*i+!.. $4uation 5&6 "here is the solids fraction of the slurry )state y mass/
+ *i+!.
Tails
+!N-
B0!4+
Concentrate s Tails
0++!B
-!N-
.!4
4N!B
%a3le '. *eights of the Concentrates and Tails
is the solids density is the slurry density
In the e:periment, the "eights of the tailings "ere not ta6en, and "ere 3ust simply sutracted from the otained "eight of concentrates! From Tale +, it can e oserved that the concentrates "eighed higher than the tails thus high percentage of concentrate has een recovered! This is ecause the ore eing utili$ed have already undergone flotation! In a asic flotation circuit, this portion is considered 1cleaning2 stage "here the level of pulp is 6ept lo" to maintain a deep froth and a high grade concentrate!
is the li5uid density
Inputting the data, "e have& 18 100
=
(−1 ) ( 2.34 −1) 2.34
¿ 1.115 g / mL Sho"n elo" is the calculation for getting the specific amount of pulp composition for 0m? solution!
Ms + Mw = Mp
$4uation 5'6
Vs + Vw=Vp =1000 mL
$4uation516
*here Ms is the mass of dry solids, M" is the mass of "ater and Mp is the mass of pulp! Js is the volume of solids, J" is the volume of "ater and Jp is the pulp volume "hich is at 0m? solution! =elating it "ith density, "e have&
ρ=
Mass o Mass= ρV Volume
$4uation 526
4!B Advantage and disadvantage of flotation over mineral dressing or concentration process! Gased on the e:periment done, it can e seen that flotation utili$es the difference in surface properties of the valuale minerals and the un"anted gangue! It "as ale to clean the concentrates of ores! It is therefore advantageous for lo" grade and comple: ore odies, especially the sulphides! The flotation performance can also e controlled and altered y the flotation reagent! %o"ever, the offset is that the process e:pensive and 5uite comple: ecause it re5uires specific 5uantities for the operation to proceed efficiently! Flotation is also disadvantageous in dealing "ith ore having e:cessive slimes! 4! Gasic principles flotation!
Comining + K B "e have& $4uation 576 LsJs H L"J" L pJ p +!4B)Js/ H 0)J"/ 0!00)0/ Using 4 to sustitute for J"& +!4B)Js/ H 0)0(Js/ 0!00)0/ $4uation 506 Js !+ m? Ms 8 '99.(' grams :; 8 <&2.&( mL These are the needed components to ma6e a pulp of 0 solids y "eight!
The overall principle of flotation is to select the fine particles y attaching it to air ules, and the heavy particles are left elo"! This is done y aeration and adding chemicals )collectors and frothers/ to the slurry in order to impart the mineral8s hydrophoicity )minerals attach to the ules/ and to ensure the staility of the froth! 9ne of the chemicals used in this e:periment is @ASC9? 4B)SE/, a collector! *hen all the collected minerals are in the froth at the surface, it is then retrieved y scraping! 4!- Difference et"een sulfide and o:ide flotation
4!4 Flotation Tests =esult Trial
;roduct
0
Concentrate s
*eight )g/ 00.!0
*eight !-
In sulfide flotation processes, there are t"o mechanisms y "hich particles are transferred from the flotation pulp to the concentrate& adhesion to air ules and natural flotation, and entrainment in froth! The entrainment mechanism is particularly
Flotation ! Submitted to Engr. Leaniel C. Silva, Instructor. ;age 1 of 0
important for particles of non–sulfide gangue, "hich do not adsor collector! The importance of controlling the recovery rate of "ater "as illustrated in plat test "or6 in "hich selectivity et"een valuale sulfides and sulfides gangue, and et"een valuale sulfides and non(sulfide gangue, "as altered y manipulating variales affecting the "ater recovery rate! Flotation of o:ide minerals on the other hand is controlled y numer o factors such as surface potential and soluility of the mineral, concentration and type of various inorganic, properties of the collector, p%, ionic strength and temperature! The role of these factors depends on the mechanisms of adsorption of the collector inorganic or polymer additives! The ma3or mechanisms include electrostatic interaction, chemical adsorption, chain to chain interaction et"een adsored collector species and modification of the surface y inorganic! 4!- Analy$ing ;arameters
The flotation time provides enough time to separate the concentrates from the tailings! Effect of flotation time actually depends on the si$e of particles and the specific gravity of the minerals! It also depends on the reagents used in the further procedure of the process! Mineral recovery increases significantly as the time increases! ?i6e any other processes of concentration in mineral processing, particle si$e largely affects the recovery of the concentrates! That is, the smaller the particles and the more uniform they are, the higher the recovery rates are! This is ecause larger surface areas of the particles are e:posed to the chemicals added in flotation' also, difference in densities is greater if the particles to e separated are of the same diameter! 9n the other hand, p% also affects the flotation process! Flotation, as mentioned aove, ma6es use of surface properties )charges/ difference of the minerals! And the chemicals added changes the surface properties of these minerals in order to retrieve them! Therefore, if the p% is B and aove, the electrical charges of the system is generally negative and it8ll affect greatly in the hydrophoicity imparted y the collectors in the system y interfering in the surface charges involved! Conditioning time also has a pronounced effect on the recovery of valuale minerals and on the grade of concentrate! Flotation rate, recovery, and grade of concentrates are directly proportional to the conditioning time! That is, flotation rate, recovery of valuale minerals, and grade of concentrates increase as conditioning time also increases until the limit is reached! Selection of reagents must also e done "ith careful consideration! It is essential that the
reagents are fed smoothly and uniformly to the slurry! Increase in collector dosage increases mineral recovery until e5uilirium is reached! Geyond "hich, further addition may either have no effect, or a slight reduction in recovery may occur! The gangue recovery also increases "ith collector addition!
2. C+NCL/*+N #N R $C+MM$N#%*+N The effect of flotation time, feed si$e, p%, pulp density, conditioning time and reagents dosages on the "ettaility of the particle "ere not determined due to unavailaility of material! @evertheless, the students "ere ale to 6no" the process of froth flotation and ho" the Denver flotation cell is operated! The students "ere also ale to determine the specific gravity of the ore and "ere ale to prepare the right amount of components to create a pulp of certain percent solid needed for flotation process! The principle of flotation "as studied and functions of reagents "ere determined! It is concluded that flotation time, feed si$e, p%, pulp density, conditioning time and reagents dosages on the "ettaility is an essential factor in operating flotation process thus it is strongly suggested for the laoratory to have ade5uate materials for it!
7. R $F$R$NC$ 0! Metso )+-/ Gasics in Minerals ;rocessing, th Edition, Section B – Separations, Metso Minerals! +! Mc>ay, O!D!, Foot, D!
Flotation ! Submitted to Engr. Leaniel C. Silva, Instructor. ;age 2 of 0
-! Phang, Oian(
Flotation ! Submitted to Engr. Leaniel C. Silva, Instructor. ;age 7 of 0
Cyanidation of
