Availability and potential utilization of byproduct gypsum in Florida phosphate operations ( FGS: Special publication 18 )

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Material Information

Title:
Availability and potential utilization of byproduct gypsum in Florida phosphate operations ( FGS: Special publication 18 )
Physical Description:
iii, 9 p. : ill., map ; 23 cm.
Language:
English
Creator:
Sweeney, John W.
Timmons, Bobby J ( joint author )
United States -- Bureau of Mines
Publisher:
Bureau of Geology, Division of Interior Resources, Florida Dept. of Natural Resources
Place of Publication:
Tallahassee, Fla.
Publication Date:
Copyright Date:
1973

Subjects

Subjects / Keywords:
Gypsum   ( lcsh )
Phosphate industry -- By-products   ( lcsh )
Genre:
government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )

Notes

General Note:
Florida Bureau of Geology special publication number 18
General Note:
"Published ... in cooperation with United States Department of the Interior, Bureau of Mines."
General Note:
"Reprinted from Proceedings, 8th Forum on Geology of Industrial Minerals, Public Inf. Circ. no. 5, 1973, Iowa Geological Survey."
Statement of Responsibility:
by John W. Sweeney and Bobby J. Timmons.

Record Information

Source Institution:
University of Florida
Holding Location:
University of Florida
Rights Management:

The author dedicated the work to the public domain by waiving all of his or her rights to the work worldwide under copyright law and all related or neighboring legal rights he or she had in the work, to the extent allowable by law.
Resource Identifier:
ltqf - NOT FOU
notis - AAR3338
alephbibnum - 000147117
oclc - 01981570
lccn - 75622514
System ID:
UF00000468:00001


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Table of Contents
    Front Cover
        Front Cover 1
        Front Cover 2
    Title Page
        Page i
        Page ii
    Table of Contents
        Page iii
    Main
        Page 1
        Page 2
        Page 3
        Page 4
        Page 5
        Page 6
        Page 7
        Page 8
        Page 9
    Back Cover
        Page 10
        Page 11
Full Text











STATE OF FLORIDA.
DEPARTMENT OF NATURAL RESOURCES
Randolph Hodges, Executive Director




DIVISION OF INTERIOR RESOURCES'
R... Vernon, Director




; BUREAU OF GEOLOGY
; ,, , .


















C. W. Hendry, Jr., Chief




SPECIAL PUBLICATION NO. 18



rh% C AVAELeABILITY AND POTENTIAL UTILIZATION
S. OF BYPRODUCT GYPSUM IN FLORIDA
PHOSPHATE-OPERATIONS




By
John W. Sweeney and Bobby J. Timmons
". . ., .






































Published by
F BUREAU OF GEOLOGY
DIVISION OF INTERIOR RESOURCES
FLRIDA DEPARTMENT OF NATURAL RESOURCES
in cooperationwith
UNITED STATES DEPARTMENT OF THE INTERIOR
,.A BUREAU OF MINES



TALLAHASSEE
S193
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STATE OF FLORIDA
DEPARTMENT OF NATURAL RESOURCES
Randolph Hodges, Executive Director



DIVISION OF INTERIOR RESOURCES
R. O. Vernon, Director



BUREAU OF GEOLOGY
C. W. Hendry, Jr., Chief



SPECIAL PUBLICATION NO. 18


AVAILABILITY AND POTENTIAL UTILIZATION
OF BYPRODUCT GYPSUM IN FLORIDA
PHOSPHATE OPERATIONS




By
John W. Sweeney and Bobby J. Timmons




Published by
BUREAU OF GEOLOGY
DIVISION OF INTERIOR RESOURCES
FLORIDA DEPARTMENT OF NATURAL RESOURCES
in cooperation with
UNITED STATES DEPARTMENT OF THE INTERIOR
BUREAU OF MINES
Reprinted from Proceedings, Eighth Forum on Geology of Industrial Minerals,
Public Inf. Circ. No. 5, 1973, Iowa Geological Survey.
TALLAHASSEE
1973












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CONTENTS


Page


Abstract ........................
Introduction ......................
Availability .......................
Uses . . . . . . . . . . . . . .
Current . . . . . . . . . . . . .
Potential ........................
Conclusions .......................


...............1
...............1
...............1
. . . . . . . .7
. . . . . . . ..7
. . . . . . . .7
. . . . . . . .9
.1ee ee e e e
.1ee le ~ o o
.1oe oe e e e
.oe e e e o e 7
.ee e e e e e 7
.7ee ee e e e


ILLUSTRATIONS


Figure

1 Location of byproduct gypsum in Florida . . . . . . . . . . ..2
2 Aerial view showing stacked byproduct gypsum . . . . . . . . .. .4
3 Aerial view showing stacked gypsum waste, water reservoir, and acid plant .... ..5
4 Panoramic view showing stacked gypsum, waste acid plant, gypsum discharge pipeline,
and waste disposal area ................................6


TABLES


Table


1 By product gypsum inventory in Florida 1972 . . . . . . . . .3
2 Analysis of slurry of byproduct gypsum . . . . . . . ..... . ... 6









AVAILABILITY AND POTENTIAL UTILIZATION
OF BYPRODUCT GYPSUM IN FLORIDA
PHOSPHATE OPERATIONS
by
John W. Sweeney' and Bobby J. Timmons2
Abstract

The generation rate and availability of byproduct gypsum in Florida is assessed to determine
the magnitude of the situation and to stimulate the utilization of this gypsum resource. Past
trends are projected to determine the future availability of these materials.
Several new uses of byproduct gypsum could utilize large volumes of the material. The
projected annual generation rates of byproduct gypsum from wet-process phosphoric acid
manufactured in Florida far exceeds domestic gypsum demand.
Known, potential, and new uses of byproduct gypsum are reviewed and discussed in this
paper.
Introduction

During the past two decades, there has been a constant shift in the United
States toward using multinutrient and mixed fertilizer materials in place of
single-nutrient materials. This trend has brought about the localization,
especially along the Gulf Coast and in Florida, of large raw-materials-oriented
chemical companies manufacturing wet-process phosphoric acid, which is the
basic material needed to produce high-analysis multinutrient fertilizer. This
manufacture of wet-process phosphoric acid results in the generation of large
quantities of impure byproduct gypsum.
The objective of this paper is to stimulate thought toward the utilization
of these vast amounts of byproduct gypsum, for the most part stacked on the
surface and available at very low cost. More complete utilization of our
mineral wastes would certainly improve the environmental picture and
possibly solve some of our mineral resource problems. We would like to
discuss the magnitude of the problem, review some of the past research, and
try to move toward a solution to finding economic uses for these materials.
Our objective is really twofold: to find a high-volume use for this material that
would increase our resource base; and to solve an aesthetic problem by
eliminating the huge mountains of materials and they do look like
mountains on the flat Florida terrain.

Availability

The availability of byproduct gypsum depends on the amount of
phosphate rock used in the manufacture of wet-process phosphoric acid.
The principal reaction taking place in the manufacture of wet-process
phosphoric acid is best represented by the following equation:
Cal0(PO4)6F2 + 10H2SO4 + 20H20 -.
10CaSO4. 2H20 + 6H3PO4 + 2HF
'U.S. Bureau of Mines Liaison Officer, Tallahassee, Fla.
2Economic Geologist, Florida Department of Natural Resources, Tallahassee, Fla.











The process is carried out in the digestion system over a period of about
eight hours. The reaction itself is completed in a matter of minutes, but
additional time is needed to allow for the proper formation of the gypsum
crystals. Sulfuric acid (93 percent H2SO4) and finely ground phosphate rock
are continuously added to a slurry consisting of reactants, products, and
sufficient recycling weak phosphoric acid to maintain sufficient fluidity. The
slurry is continually drawn off and filtered.
The gypsum filter cake is reslurried with water and usually discarded.3
Large volumes of byproduct gypsum are available in Florida. For every ton of
phosphate rock processed to phosphoric acid, approximately one and one-half
tons of byproduct gypsum are generated.


Figure 1. Location of byproduct gypsum in Florida.


Let's look at the magnitude of the situation. Figure 1 shows the location
of the phosphoric acid plants in Florida and the location of the stacked
gypsum.
Table 1 lists the companies generating the gypsum, the acreage needed
for storage, the annual generation rate, and current inventories of stacked
gypsum.



'Bixby, David W., Delbert L. Rucker, and Samuel L. Tisdale. Phosphatic Fertilizers, Properties
and Processes. Wet Process Phosphoric Acid. Sulphur Institute, October 1966, p. 9-11.





Agricola

U.S.S. Agri-Chemicals,
Bartow 80 1,500,000
Ft. Meade 80 600,000

Totals 1,773 20,900,000

1 Data obtained through personal communication with individual
companies.
2 Sold Harding Plant to Conserv, Inc., June 1971.


3


5,000,000
6,000,000

152,700,000


TABLE 1. By product gypsum inventory in Florida-19721

Company Acres Annual Generation Available
Rate Tons
Tons/Year

Agrico Chemical Company, 250 1,000,000 6,000,000
Pierce

Brewster Phosphates, 70 13,500,000
Brewster

Borden, Piney Point 100 900,000 3,700,000

Cities Service, 260 5,500,000 45,000,000
East Tampa

Central Phosphates, 100 1,000,000 6,000,000
Zephyrhills

C. F. Chemicals, Inc. 200 2,500,000 24,000,000
Bartow

Farmland Industries, 60 2,300,000 6,000,000
Green Bay

W. R. Grace, Bartow 75 1,600,000 16,000,000

Mobil Chemical Company, 2 300 9,000,000
Nichols

Occidental, White Springs 100 1,000,000 4,000,000

Royster, Mulberry 48 3,000,000 5,000,000

Swift & Company, 50 3,500,00














Summarizing, we see that there are over 152 million tons of gypsum
currently available (1972), and the material is being generated at the rate of 21
million tons annually. Byproduct gypsum generated during 1971 was about
one-half of the 1969 world production of primary gypsum, and almost three
times that of the domestic production of natural gypsum.4
Without making any sophisticated projections, taking growth rates of the
wet-process phosphoric acid industry and other factors into consideration,
but just at the current growth rate, over the next ten years there will be over
200 million tons of byproduct gypsum generated in Florida, and that's more
than doubling the amount of material that is already stacked on the ground.
Let's look at some of this material. Figure 2 shows an oblique aerial
photograph showing the largest single amount of byproduct gypsum available
in the central Florida area.


Figure 2. Aerial view showing stacked byproduct gypsum.


4Ashizawa, Roy Y. Gypsum. BuMines Minerals Yearbook-1969, v. 1-2, 1971, p.547


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Figure 3 is an aerial view showing stacked byproduct gypsum and the
water retention areas.


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Figure 3. Aerial view showing stacked gypsum waste, water reservoir, and acid plant.


mm --_






Figure 4 is a panoramic view showing byproduct gypsum, the gypsum
discharging in a mined area, and waste water return lines.



















Figure 4. Panoramic view showing stacked gypsum, waste acid plant, gypsum discharge pipeline,
and waste disposal area.
Now that we have briefly examined the magnitude of the available
byproduct, let's look at some of the physical and chemical characteristics of
the material which may dictate its use.
Physically, the crystalline forms of the byproduct gypsum are unlike the
gypsum used to make building products, which have flatsided crystals. The
byproduct gypsum crystal is jagged and/or acicular, and therefore does not
bond favorably in the manufacture of gypsum building products.
Table 2 shows the chemical analysis of a typical byproduct gypsum
sample. The material has a lower calcium sulfate content than the naturally
occurring material used for building products. However, by simple screening,
much of the silica can be removed. That still leaves the deleterious fluorine
and phosphoric acid, which limits the use of byproduct gypsum.
TABLE 2 Analysis of Slurry of Byproduct Gypsum
Gypsum Percent
Acid insoluble, incl. SiO2 3.52
Acid soluble, P205 0.66
Fas CaF2 1.42
Calcllm Sulfate (CaSO4) 73.25
Combined water 18.21
R203 (Fe+Al oxides) 0.54
Chlorine as NaCI 0.03
Carbonate as CaCO3 1.00









Uses


Current

Several companies in central Florida have mines adjacent to their
phosphoric acid plant. In these cases, the companies utilize the mined-out
areas as gypsum disposal areas putting 30 to 40 feet of the gypsum below the
surface. These areas "can be" dressed off, when the gypsum is filled to grade,
to create reclaimed land. Figure 4 is an example of this use. This type of
disposal is limited, however, because the acid plant location is not always in
close proximity to a mined-out area.
At the present time, in Florida, very small amounts of this byproduct
gypsum are being sold and used.as land plaster in the peanut growing areas of
northern Florida and southern Georgia and Alabama. Minor amounts (10,000
to 15,000 tons annually) are also being used in the Tampa, Fla., area as road
base stabilization material. It has also been reported that in Winnfield, La.,
natural gypsum and anhydrite is used extensively as road base stabilization
material and as an asphalt filler (up to 30 percent).5

Potential

The potential uses for byproduct gypsum are-the same as the uses of
naturally occurring gypsum, but with the added problems of lower grade and
impurities. Therefore, the material must be beneficiated in some manner
before it can be used for normal applications. Some of the potential uses for
this byproduct gypsum are as follows:
1. Utilization for agricultural pruposes land plaster.
2. Converting to sulfur or sulfuric acid and cement.
3. Various calcined gypsum products.
4. Cement production retarderr).
5. Road base stabilization.
6. Asphalt filler.
What use can be made of this tremendous tonnage of gypsum derived
from the production of wet-process phosphoric acid? Some of the current uses
have been listed; each, however, with the possible exception of using the
material as road-base stabilization, would only utilize minor amounts.
Evaluating each of the listed uses, there is only a limited market for the
gypsum for agricultural uses, about 20,000 tons per year. Converting the
gypsum into sulfur or sulfuric acid and cement becomes less attractive as
sulfur supplies become more abundant. Using the, gypsum as a cement
retarder would only have limited usage, and it would be expensive to remove
the impurities.
The Japanese have developed a process to produce gypsum in a related
wet-process phosphoric acid method; but rather than be in the business of

SPersonal communication from Dr. B. F. Buie, Geology Department, Fla. State University,
Tallahassee, Fla.









producing phosphoric acid as we are in the United States, their process is
designed to produce hemihydrate gypsum with phosphoric acid as the
byproduct. The hemihydrate is then reslurried with cold water to recrystallize
the gypsum into coarsely crystalline dihydrate gypsum. This material
compares favorably with natural gypsum.for the manufacture of the various
gypsum products.
In Europe, gypsum is calcined at high temperatures along with coke,
silica, and clay and is used to produce sulfuric acid and a cement clinker. 6
More recently, Gebr. Giulini Gmb H. of Ludwigshafen, West Germany, has
developed a process that offers an attractive low-cost potential for byproduct
gypsum from wet-process phosphoric acid.7 The process converts the material
into hemihydrate powder used to make building blocks. The end product is
calcium sulfate hemihydrate in alpha form, which has more favorable
properties than beta-hemihydrate produced by dry calcination. The process
also substantially lowers the impurities of fluorine and phosphorus pentoxide,
which are present in the gypsum feed, so that they present no problems in the
final product. According to Giulini, the final product, either as powder or as a
cast construction element, compares favorably with most products made from
natural gypsum. For example, a plant at Ludwigshafen, West Germany,
processes 165 tons per day of CaSO4.2H20 at a total production cost of $4.10
per ton of hemihydrate. The economics will vary between locations, but the
figures presented are interesting and within an economically attractive range.
A plant to process gypsum for utilization of sulfur content was
established in Texas but had to close because the lowering of sulfur prices due
to the abundance of sulfur from natural gas made the plant operation
uneconomical.
The U.S. Bureau of Mines has conducted considerable research to
develop methods to economically convert the byproduct gypsum into gypsum
products... Preliminary tests conducted at the Bureau's Salt Lake City
Metallurgy Research Center, Salt Lake City, Utah, on gypsum from the
Simplot operation near Pocatello, Idaho, indicates that byproduct gypsum
can be calcined and used as various plaster products including floor and roof
fillers, plaster board, Keen's cement, land plaster, and fiber-reinforced wall
plaster for undercoats.
Gypsum waste from a Florida operation was also tested to determine the
feasibility of processing the material into plaster of paris. The main impurities
in the Florida byproduct gypsum was silica sand. The color of the final gypsum
product was acceptable, but the plaster tended to crumble under minor loads.
By repeated screening, the silica sand content (5 percent) was reduced to 2.5
percent. This fraction, however, was abundant enough (minus 250 mesh) to
be detected by x-ray diffraction methods.



6Chemical Week. They're Moving Gypsum Mountains. August 3, 1968, v. 103, pp. 37-38.
7Ellwood, P. Turning Byproduct Gypsum Into a Valuable Asset. Chemical Engineering, March
24, 1969, v. 76, pp. 106-108.










Conclusions


Let's review what we have been talking about. There are 152 million tons
of byproduct gypsum on the ground and it is being generated at the rate of 21
million tons per year a staggering figure!
What can we do with this material that doesn't present an environmental
threat or hazard as some mineral wastes do, yet it does present an aesthetic
problem? In ten years, we will add 200 million tons to the stacks; in 30 years,
we will add 600 million tons to the stacks. Where does it stop? We must
advance technology, we must devise economic processes and uses for this
material or methods to dispose of it economically. I know what you are
thinking about now we have enough gypsum being generated in Florida to
plaster the earth and then some.
Our purpose in presenting this paper is to stimulate thought. Where can
you find a low-grade ore containing two valuable coproducts (fluorine and
phosphorus pentoxide) already mined and available for next to nothing and in
some cases nothing. Yes, many processes have been developed and we know of
minor uses but let's not be satisfied; let's keep hammering away until we can
come up with answers. I'll leave you with that thought.














































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