Thesis_2.doc

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Chapter 2

In-Plant Testing of HydroFloat Separator in Phosphate Industry

2.1 Introduction

2.1.1 General

Teeter bed technologies can only be applied to mineral systems that have a particle size range

and density differences are within acceptable limits. The CrossFlow separator requires a

moderately large difference in particle densities. The unit inherently accumulates low density

coarse particles at the top of the teeter bed, which are too light to penetrate the bed, but at the

same time, too heavy to be carried by the rising water into the overflow. As a result,

misplacement of low-density, coarse particles to the high-density underflow can occur. This

inefficiency can be partially corrected by increasing the elutriation water, to try to carry the low

density coarse particles into the overflow however this can sometimes cause the fine, high-

density particles to also report to the overflow instead of penetrating the teeter bed. !ndustry

representatives identified the need to develop an air assisted hydraulic concentrator that would

combine the fle"ibility of a flotation process with the high capacity of a density separator to

overcome the inefficiencies of the CrossFlow separator.

The limitations of the CrossFlow separator were recognized and overcome through the design of

the #ydroFloat separator. The #ydroFloat can theoretically be applied to any mineral

classification system where differences in apparent density can be created by the selective

attachment of air bubbles. !t incorporates a flotation process with the high capacity of a density

separator. Figure $.% is a schematic of the #ydroFloat separator.

%


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#igh &ensity

'ow &ensity

(ubbles

Teeter (ed

!nterface

Float

)roduct

*ater

Addition

Float

+e,ect

&ewatering

Cone

-eparation

Chamber

Feed

Circulation

'oop

.lutriation

/etwo r0

Figure 2.1. Schematic draing of HydroFloat separator

The device operates similar to a traditional CrossFlow separator with the feed settling against an

upward current of fluidization water. 1nli0e the CrossFlow, the #ydroFloat utilizes compressed

air and a small amount of frothing agent in the fluidization water to produce fine air bubbles.

+eagentized feed is introduced into the top of the separator where the feed particles are allowed

to settle based on their size and2or density. )reviously treated with a collector to ma0e one or

more of the minerals hydrophobic, the particles within the separation chamber attach to the small

bubbles, reducing their effective density. These lighter bubble-particle aggregates rise through

the separation chamber, through the teeter bed and overflow the top of the #ydroFloat separator

$


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into the product launder. The hydrophilic particles move down through the teeter bed and are

eventually discharged through the control valve at the bottom of the separator.

2.1.2 !d"antages of a Hydraulic separator o"er con"entional froth flotation cells

The use of a fluidized bed over conventional flotation significantly improves the recovery of

particles by 3i4 reducing turbulence, 3ii4 enhancing buoyancy, 3iii4 increasing particle retention

time, and 3iv4 improving bubble-particle contact.

The presence of the high-solids teeter bed reduces the turbulence commonly associated in

traditional flotation units and therefore enhances the buoyancy of the particles. The teetering

effect of the hindered-bed relinquishes the need for bubble-particle aggregates to have sufficient

buoyancy to rise to the top of the cell. The low density agglomerates can easily overflow into the

product launder, where as the hydrophilic particles move through the teeter bed and eventually

discharge through the control valve at the bottom of the separator.

5ther benefits of the #ydroFloat separator versus traditional froth flotation cells include

increases in particle retention time by producing a counter-current flow of particles settling in a

hindered state against an upward rising current of water, and the increased probability of bubble-

particle contacting in the teeter-bed due to the high-solids content. A higher production rate is

possible with the #ydroFloat separator than in traditional froth flotation cells due to the high

percent solids in the compact teeter bed.

6


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The #ydroFloat separator is ideally suited to recover coarse particles that traditional froth

flotation cells cannot efficiently recover for several reasons. 5ne reason for the improved

recovery of coarse particles is the upward flow of elutriation water in the #ydroFloat separator

helps lift the larger particles into the product launder. econd, the teeter bed produces ideal

conditions for bubble-particle interactions by maintaining high solids content and quiescent flow

conditions. !n addition, the high solids content within the teeter-bed separator ma0es it possible

to treat large tonnages in a very compact volume as compared to conventional flotation

separations which are conducted at very low solids contents using large volume cells.

2.1.# Pro$ect %ustification

5ne of the driving forces behind the #ydroFloat separator is the phosphate industry7s need to

recover coarse particle phosphate 38$9 " 6:; size fraction4 from the feed matri". !t is estimated

that %?.:-%: million of

revenues.

As in the coal industry, the energy benefits of the #ydroFloat over conventional equipment are

related to the reduction in pumping requirements and water usage which is a direct result of the

higher feed ton rate. The lower operating and maintenance cost per ton of product is

significantly reduced with the #ydroFloat versus conventional equipment. 5verall, the

implementation of the #ydroFloat separator will allow operations to become more profitable and

@


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more competitive by utilizing reserves more effectively, reducing waste and increasing

productivity.

:


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2.2 &iterature 'e"ie

2.2.1 General

The recovery of minerals by flotation is one of the most versatile mineral-processing techniques

used in industry today. Flotation methods are utilized throughout the mining industry to treat

sulfide ores such as copper, lead and zinc, o"ide ores such as hematite and cassiterite and non-

metallic ores such as phosphate and coal 3*ills, %$4. ince its inception in the early %


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reduction in the flotation rate of the particles 3Bameson, %??4. !t can be seen that the efficiency

of the froth flotation process deteriorates rapidly when operating in the e"tremely fine or coarse

particle size ranges, which is considered between %


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The variety of flotation machines available on the mar0et today can be classified into two

distinct groupsG pneumatic and mechanical machines 3*ills, %$4. )neumatic machines

commonly utilize air that is blown in or induced, where it must be dissipated through a series of

baffles or some form of permeable base within the cell. ince air is used not only to produce the

froth and create aeration but also to maintain the suspension and to circulate it, an e"cessive

amount is usually introduced 3*ills, %$4. Complications directly related to the e"cessive

amount of air limited the use of pneumatic machines until the development of the flotation

column.

;echanical flotation machines are the most common and widely used flotation machine on the

mar0et today. The units are characterized by a mechanically driven impeller which agitates the

slurry and disperses the incoming air into small bubbles 3*ills, %$4. Air addition into the cell

can either be forced through an e"ternal blower, or self-aerating. Typically most mechanical

flotation cells are set up in a series of Jban0sK, where several cells will allow free flow from one

cell to the ne"t down the ban0.

)erformance is generally based on three factors includingG 3i4 ;etallurgical performance, i.e.,

product recovery and grade, 3ii4 Capacity, and 3iii4 5perating and maintenance costs 3*ills,

%$4. An analysis of the effectiveness of the various types of flotation machines was made by

Loung 3%9$4, who discusses performance with regard to the basic obectives of flotation, which

are the recovery of the hydrophobic species into the froth product, while still achieving a high

selectivity by retaining as much as the hydrophilic species as possible in the slurry. +ecovery is

directly related to particle-bubble attachment and requires quiescent conditions, which is not

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found in conventional mechanical flotation devices. The mechanical impellers found in typical

flotation cells are not ideal for particle-bubble contact, which has led the industry to utilize

column cells for a variety of mineral applications that, up until the past decade or two, was

unheard of.

Column cells are considered to be ideal displacement machines, where as mechanical cells are

ideal mi"ers 3*ills, %$4. A column cells improves recoveries by minimizing turbulence within

the cell and froth washing. !n %%@, .;. Callow patented the first apparatus with air sparging

through a porous false bottom, 3+ubinstein, %:4, which would become the basis for future

column cell designs. (y %%, ;. Town and . Flynn had developed the first design involving a

countercurrent of slurry and air within a column. And while pneumatic Callow apparatuses were

very popular in the early %$


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2.2.# Phosphate Flotation

)hosphate beneficiation plants are designed to process run-of-mine ore, typically called the ore

matri", into a sellable product for use in either the fertilizer mar0et or as an integral part or the

production of phosphoric acid. The ore matri" is upgraded by separating the phosphate grains

from other impurities such as clay and silica. (eneficiation plants in the outheastern 1nited

tates 3Florida and /orth Carolina4 generally use sizing and classification processes to

concentrate the phosphate roc0 and separate it from impurities.

Florida beneficiation plants typically wash and deslime the ore matri" at %:< mesh. The material

finer than %:< mesh is considered tailings and is pumped to settling ponds. Appro"imately 6


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The industry, however, has ta0en other approaches to circumvent the problem of low floatability

of coarse particles. For instance, such approaches are e"emplified by the use of gravitational

devices such as spirals, tables, launders, sluices and belt conveyors modified to perform a Ns0in

flotationN of the reagentized pulp. Although a variable degree of success is obtained with these

methods, they have to be normally supplemented by scavenger flotation. !n addition, some of

them require e"cessive maintenance have low capacity or high operating costs. Their

performance is less than satisfactory and in certain cases their use has been discontinued.

)revious laboratory and pilot-scale testing of the #ydroFloat separator has proven its capabilities

as an effective flotation device for recovering fine and coarse phosphate. The unit has especially

proven successful in the 86: mesh fraction of the phosphate ore matri" in Florida. This size

fraction was previously discarded to the tailings when detachment and buoyancy limitations in

traditional flotation methods failed to recover the material.

%%


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2.# In-Plant Testing at Phosphate Plant ! (I)C*

The )hase ! field-testing of the #ydroFloat separator involved 3i4 equipment setup, 3ii4

sha0edown testing, and 3iii4 detailed testing at the )hosphate )lant A. The goal of this effort was

to compare the unit to e"isting conventional cells in several different areas of the plant by

analyzing the anticipated product grade and recovery, insol content, reagent consumption, and

feed capacity at, and above, design feed rates of the unit. The three areas of the plant where the

#ydroFloat separator was tested included the fine feed, amine flotation and coarse feed circuits.

The main obective of the fine and coarse phosphate testing was to demonstrate the potential of

the unit as a candidate for the process equipment in a proposed plant design with both fine and

coarse circuits. The main obective of the amine flotation testing was to demonstrate the

feasibility of using the unit for silica flotation and to develop data to determine its potential

application for use in the amine flotation circuit at )hosphate )lant A. Appro"imately months

was allocated to this tas0.

!ndividuals from riez ;agnetics and Iirginia Tech participated in the testing at )hosphate )lant

A with cooperation from 0ey personnel at the processing plant. Additional tests were conducted

by )hosphate )lant A representatives to e"pand the data base for evaluating the potential of

incorporating the #ydroFloat separator into proposed circuit upgrades.

%$


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2.#.1 +,uipment Setup

2.#.1.1 Fine Circuit

This tas0 focuses on the installation of the pilot-scale unit in the fine feed circuit at )hosphate

)lant A. The separator was transported from the riez ;agnetics Central +esearch 'ab in rie,

)A to the processing plant. *ith cooperation from the operators and mechanics at the plant, the

%9-inch diameter, pilot-scale #ydroFloat separator was installed at the fine circuit at )hosphate

)lant A as shown in Figure $.$. +eagentized feed was supplied to the #ydroFloat separator

through a two-inch line connected to the e"isting plant conditioning tan0s. Concentrate and

tailings streams were discharged into floor sumps.

The unit was operated asa column flotation cell, utilizing the #ydroFloat separator air sparging

system. The test unit included 6 compartments that allowed more water and air to be added 3up

to < gpm water and %< cfm air4. There was no teeter-bed required in this system. )lant

compressed air and %%: volt electrical power were connected to the separator for the automated

control system. The separator was automatically controlled through the use of a simple )!&

control loop which includesa pressure sensor mounted on the side of the separator to measure

the relative pressure 3level4, a single loop )!& controller, and a pneumatic pinch valve to control

the underflow discharge to maintain a constant bed pressure 3level4.

%6


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Figure 2.2. 1-inch iameter Pilot-Scale HydroFloat Separator Test Circuit

2.#.1.2 !mine Circuit

The same separator used in the fine circuit was also used in the amine flotation circuit. *ith

cooperation from the operators and mechanics at the plant, the %9-inch diameter, pilot-scale

#ydroFloat separator was installed in the amine circuit at )hosphate )lant A. +eagentized feed

was supplied to the #ydroFloat separator through a two-inch line connected to the e"isting plant

conditioning tan0s. Concentrate and tailings streams were discharged into floorsumps.

%@


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The unit was operated as acolumn flotation cell, utilizing the #ydroFloat separator air sparging

system. The test unit included 6 compartments that allowed more water and air to be added 3up

to < gpm water and %< cfm air4. There was no teeter-bed required in this system. )lant

compressed air and %%: volt electrical power were connected to the separator for the automated

control system. The separator was automatically controlled through the use of a simple )!&

control loop which includesa pressure sensor mounted on the side of the separator to measure

the relative pressure 3level4, a single loop )!& controller, and a pneumatic pinch valve to control

the underflow discharge to maintain a constant pressure 3level4.

2.#.1.# Coarse Circuit

The same separator used in the fine and amine flotation circuits was also used in the coarse

circuit, with one modification. The center compartment was removed from the unit, so as to

allow the unit to operate with a typical teeter-bed 3a total of $ compartments4. *ith cooperation

from the operators and mechanics at the plant, the %9-inch diameter, pilot-scale #ydroFloat

separator was installed in the coarse circuit at )hosphate )lant A. +eagentized feed was supplied

to the #ydroFloat through a two-inch line connected to e"isting plant conditioning tan0s.

Concentrate and tailings streams were discharged into floorsumps.

)lant compressed air and %%: volt electrical power were connected to the separator for the

automated control system. The separator was automatically controlled through the use of a

simple )!& control loop which includesa pressure sensor mounted on the side of the separator to

measure the relative pressure, a single loop )!& controller, and a pneumatic pinch valve to

control the underflow discharge to maintain a constant bed pressure.

%:


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2.#.2 Sha/edon Testing

After completing the installation of the test #ydroFloat unit, preliminary sha0edown testing was

conducted to resolve any une"pected operational problems that could arise. These tests are

normally necessary to resolve any problems that may have been overloo0ed in the initial

engineering and to confirm that feed capabilities, pipe sizes, electrical supplies, control systems,

etc., are adequate. An average of si" sha0edown tests per circuit was conducted with the unit.

2.#.# etailed Testing

Two series of detailed test programs were conducted using the pilot-scale test unit. The first

series of test were performed to investigate the effects of the 0ey design variables on separator

performance and to simultaneously define the overall grade and recovery curve.

The #ydroFloat separatoris designed for feed rates of $ tph2ft$and % tph2ft$rougher concentrate,

which allows the test unit to operate at @ tph feed and $ tph concentrate, respectively. The initial

testing in the fine and coarse circuit evaluated the unit at loading rates much higher than design

to establish the recovery fall-off. The design rates for the amine flotation circuit were not

precisely 0nown going into the testing, but were thought to be similar to those for rougher

flotation. )art of the amine testing program was devoted to determining the design rates and

evaluating the #ydroFloat separator performance across the board, both at the design rate and

above.

%


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*ith the recovery fall-offdetermined for each circuit and unit configuration, the subsequent

series of testing was used to investigate the effects of 0ey operating parameters. Tests were

conducted to establish reagent consumption 3fatty acid, surfactant, amine and diesel oil4, to

investigate the bed levels and sparger water required for the best unit operation and to investigate

the variability associated with the overall system. For each test, samples were ta0en from the

feed, concentrate and tailings streams after conditions were stabilized. The samples were

analyzed for ()', ;g5 and insol.

2.#.0 Process +"aluation

To ensure the test data was reliable and self-consistent, all as-received results were analyzed and

adusted using a commercially available mass-balance program. "perimental values that were

deemed by the mass balance routines to be unreliable were removed from the data set. The

participating mining company used the compiled data to establish the metallurgical

improvement, operating savings and economic paybac0 that may be realized by implementing

the proposed high-efficiency technologies.

The process evaluation has been divided into three sections including 3i4 fine feed circuit, 3ii4

amine flotation circuit, and 3iii4 the coarse feed circuit.

2.#.0.1 Fine Circuit

Fifty-three tests were conducted during the fine circuit testing at )hosphate )lant A. Testing in

the fine circuit produced an average of %


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#ydroFloat separator and plant tails percent ()' for each test. The plant *emco cells averaged

only about


19/37

Figure 2.0. 'ougher Concentrate Grade of HydroFloat Separator "ersus Plant Cells

&uring testing, several attempts were made to obtain final grade concentrates 3?= insol4 with

one stage of flotation. The results show that insol concentrates between -%


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recovered 9


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+eagent dosages were affected by the poor water quality and e"cessive slimes in the feed during

the testing program. The fatty acid dosagein the plant ranged from


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2.#.0.2 !mine Circuit

Twenty-four tests were conducted during the amine flotation circuit testing at )hosphate )lant A.

#ydroFloat separator testing in the amine flotation circuit produced an average of %.6= higher

insol concentrate and recovered about 9= less insol to the amine tailings than in the )lant

*emco Cell. Figure $. displays the concentrate grade for the #ydroFloat separator and the

plant for each test. The plant *emco cells averaged only about


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Figure 2.3. !mine Concentrate Grade Comparison of HydroFloat Separator

"ersus Plant Cells

$6


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Figure 2.4. 5P& 'eco"ery Comparisons HydroFloat Separator "ersus Plant Cells

5ne of the most important operating parameters to consider for amine flotation is the ability of

the process equipment to recover coarse silica without recovering phosphate. Comparison testing

of the #ydroFloat separator with the *emco Cell produced promising results. As shown in

Figure $.9, the #ydroFloat separator had ust slightly less recoveries than the plant for all of the

size fractions e"cept the 6: mesh, where it had a nearly = increase in ()' recovery than the

plant.

$@


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Figure 2.. Comparison of Test 'esults for !mine Phosphate (Plant Circuit 2*

+eagent dosages were affected by the poor water quality and e"cessive slimes in the feed during

the testing program. The surfactant dosage for the #ydroFloat separator ranged from


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*hile the operation of the #ydroFloat separator for amine flotation was difficult to optimize due

to various outside variables affecting the system, a significant number of tests were conducted at

differing operating variables undervarying operating conditions to achieve optimum operating

conditions. The optimum conditions for the #ydroFloat separator for use in amine flotation as

defined by this testing program areG 6 compartment sections, with bed level between ?


27/37

from $.


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Figure 2.17. 'eco"ery Comparison of HydroFloat Separator "ersusPlant Cells

Figure 2.11. Grade Comparison of HydroFloat Separator "ersus Plant Cells

$9


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The ability of the unit to recover coarse material into an acceptable concentrate proved to be

successful during the testing program. 5ne test achieved an overall ()' of $= at a feed rate of

6.$ tph 39= of design4 and a concentrate overflow froth rate of %.: tph 3?9= of design4. The

associated concentrate grade was %= ()'.

creen and chemical analyses were conducted on selected tests to determine the recovery

coefficients for various mesh sizes. The #ydroFloat separator recovery coefficients are

considered to be e"cellent asshownin Figure $.%$.

Figure 2.12. Comparison of Test 'esults for Coarse Phosphate (Plant Circuit 1*

)ercent solids in the tailings averaged ?:.9= for all tests. The #ydroFloat separator was

configured with$ compartments, with bed levels between 9$ and 9?, and with a recommended

$


30/37

level of 9:. This resulted in optimum condition ofG froth depths between %: and $< inches,

sparger water near $< gpm, and air flow at :.< cfm. The measured recovery coefficients and

concentrate grade at these design rates were acceptable. (ased on this data, the #ydroFloat can

successfully be implemented into the )hosphate )lant A coarse flotation circuit.

2.#. Sample !nalysis

&etailed analysis was conducted on each of the samples collected during the testing program.

The analyses were performed in accordance with AT; procedures onsite at the )hosphate )lant

A. +epresentative samples were collected around the pilot-scale unit. lurry flow rates for the

feed, concentrate and tailings streams were directly measured using a stopwatch and a calibrated

container. The mass and liquid flow rates were then calculated from the measured slurry flow

rates and the sample assays using the two-product formula.

2.#.3 Future 8or/

*hile the results of the testing loo0 promising, the proect has been put on hold until the

company finishes a reorganization proect.

6


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2.0 In-Plant Testing at Phosphate Plant 5 (Cargill*

The )hase ! field-testing of the #ydroFloat separator involved 3i4 equipment setup, 3ii4

sha0edown testing, and 3iii4 detailed testing at the )hosphate )lant (. The goal of this effort was

to compare the unit to e"isting conventional cells by analyzing the anticipated product grade and

recovery, insol content, reagent consumption and feed capacity at, and above, design feed rates

of the unit. The main obective of testing was to determine if the #ydroFloat separator could

achieve higher recoveries of the coarse particles than the conventional cells. Appro"imately %$

months was allocated to this tas0. !ndividuals from riez ;agnetics and Iirginia Tech

participated in the testing at )hosphate )lant ( with cooperation from 0ey personnel at the

processing plant.

2.0.1 +,uipment Setup

The separator was transported from the riez ;agnetics Central +esearch 'ab in rie, )A to the

processing plant. *ith cooperation from the operators and mechanics at the plant, the %-foot

diameter, pilot-scale #ydroFloat separator was installed in the coarse circuit at )hosphate )lant

( as shown in Figure $.%6. +eagentized feed was supplied to the #ydroFloat separator through a

two-inch line connected to the e"isting plant conditioning tan0s. Concentrate and tailings

streams were discharged into floorsumps.

)lant compressed air and %%: volt electrical power were connected to the separator for the

automated control system. The separator was automatically controlled through the use of a

simple )!& control loop which includesa pressure sensor mounted on the side of the separator to

measure the relative pressure 3level4, a single loop )!& controller, and a pneumatic pinch valve

6%


32/37

to control the underflow discharge to maintain a constant bed pressure 3level4. Clarified water

was connected to the separator to create the fluidized teeter bed of solids.

Figure 2.1#. Pilot-Scale HydroFloat Separator Test Circuit

2.0.2 Sha/edon Testing

After completing the installation of the test #ydroFloat unit, preliminary sha0edown testing was

conducted to resolve any une"pected operational problems that could arise. These tests are

normally necessary to resolve any problems that may have been overloo0ed in the initial

engineering and to confirm that feed capabilities, pipe sizes, electrical supplies, control systems,

etc., are adequate.

6$


33/37

2.0.# etailed Testing

Two series of detailed test programs were conducted using the pilot-scale test unit. The first

series of test were performed to investigate the effects of the 0ey design variables on separator

performance and to simultaneously define the overall grade and recovery curve.

The #ydroFloat separator is designed for feed rates of $ tph2sqft and % tph2sqft rougher

concentrate, which allows the test unit to operate at @ tph feed and $ tph concentrate,

respectively. The initial testing in the coarse circuit evaluated the unit at loading rates much

higher than design, to establish the recovery fall-off.

*ith the recovery fall-offdetermined for each circuit and unit configuration, the subsequent

series of testing was used to investigate the effects of 0ey operating parameters. Tests were

conducted to establish reagent consumption 3fatty acid, surfactant, and diesel oil4, to investigate

the bed levels and sparger water required for the best #ydroFloat separator operation, and to

investigate the variability associated with the overall system. For each test, samples were ta0en

from the feed, concentrate and tailings streams after conditions were stabilized. The samples

were analyzed for ()', ;g5, and insol.

2.0.0 Process +"aluation

To ensure the test data was reliable and self-consistent, all as-received results were analyzed and

adusted using a commercially available mass-balance program. "perimental values that were

deemed by the mass balance routines to be unreliable were removed from the data set. The

participating mining company used the compiled data to establish the metallurgical

66


34/37

improvement, operating savings and economic paybac0 that may be realized by implementing

the proposed high-efficiency technologies. Test results were previously summarized and

reported in preceding documentation and will not be covered in detailed in this report.

2.0. Sample !nalysis

&etailed analysis was conducted on each of the samples collected during the testing program.

The analyses were performed in accordance with AT; procedures onsite at the )hosphate )lant

(. +epresentative samples were collected around the pilot-scale unit. lurry flow rates for the

feed, underflow and overflow streams were directly measured using a stopwatch and a calibrated

container. The mass and liquid flow rates were then calculated from the measured slurry flow

rates and the sample assays using the two-product formula.

2.0.3 Future 8or/

)ilot-scale testing at )hosphate )lant ( in Florida proved to be successful, and the company has

agreed to purchase a prototype #ydroFloat separator for testing against e"isting flotation cells in

the coarse recovery circuit. !nstallation of the prototype is e"pected during eptember $


35/37

2. Conclusion

%. 5ne of the goals of this proect is to successfully prove the technology in a sufficient

period of time to minimize the financial ris0 that will be ta0en by industry. The previous

years test wor0 has eliminated the uncertainties associated with the #ydroFloat separator

by proving plant scale units do in fact wor0. This can be seen by the fact that industry

leaders have submitted purchase requests for full scale units in their preparation plants.

(ased on the successful installation of these full scale units, further implementation of

additional units can be utilized in a broad spectrum of companies and industries.

$. Hey design and operating variables have been established based on the performance

capabilities of the #ydroFloat separator. From here, proof-of-concept 3)5C4 tests using a

production-scale unit can be implemented at the various test locations where full scale

prototypes are being installed. The )5C-scale tests will identify critical scale-up criteria

for the design of industrial applications. The )5C-scale tests will also be used to define

the performance capabilities of the high-efficiency processes in an industrial setting and

to fully demonstrate the potential economic benefits that can be realized with the

#ydroFloat separator.

6:


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2.3 'eferences

Florida !nstitute of )hosphate +esearch, )ublication /o.


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/orth Carolina tate ;inerals +esearch 'aboratory, )ublication /o. $-$@-), %$, J)reliminary

&esliming Tests w2 /C )hosphate 1sing a )ilot-cale 'inate" #ydrosizer,K )repared (yG

chlesinger, '. and #utwel0er, B.

+ubinstein, B.(., %:. Column FlotationG )rocesses, &esigns and )ractices. ordon and (reach

cience )ublishers, 1nited tates.

oto, #. and (arbery, ., %%, JFlotation of Coarse )articles in a Counter-Current Column

Cell,K ;inerals and ;etallurgical )rocessing, Iol. 9, /o. %, pp. %-$%.

*ills, (arry A., %$. ;ineral )rocessing Technology :thdition. )ergamon )ress. Tarrytown,

/ew Lor0.

Loung, )., %9$, JFlotation ;achines,K ;inerals ;agazine, Iol. %@, /o. %, pp. 6:.

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