DOEhlCI3 1174 -- 5342 Distribution Category UC-132

Utilization of Low N0x Coal Combustion By-Products

Quarterly Report April 1 - June 30, 1996

Work Performed Under Contract No.: DE-FC21-94MC3 1 174

For U.S. Department of Energy

Office of Fossil Energy Morgantown Energy Technology Center

P.O. Box 880 Morgantown, West Virginia 26507-0880

Bv Michigan Technoiogical University TEP %-

1400 Townsend Drive flh &-=

Houghton, Michigan 4993 1 - 1295

Portions of this document may be illegible in electronic image products. Images are produced h m the best available original dOl l rmeI l t

Disclaimer

This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or use- fulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.

UTILIZATION OF LOW NOX COAL COMBUSTION BY-PRODUCTS DE-FC21-94MC31174

PROJECT SUMMARY . SEVENTH QUARTER April 1. 1996 through June 30. 1996

TABLE OF CONTENTS

TECHNOLOGY TRANSFER .......................... : ....................... . 2 . . TASK 1.0 . TEST PLAN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.

TASK 2.0 . LABORATORY CHARACTERIZATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Task 2.1 . Sample Collection ............................................. 2 Task 2.2 . Material Characterization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Task 2.3 . Laboratory Testing of Ash Processing Operations ..................... 3

TASK 3.0 . PILOT PLANT TESTING ........................................... 3

TASK 4.0 . PRODUCT TESTING ............................................. - 3 Task 4.1 . Concrete Testing .............................................. 3

Characterization of AEP As-received and Cleaned Ash .................... 3 Concrete Performance ............................................ 7 Mechanical Properties of the Concrete ................................. 8

Task 4.2 . Concrete BlocWBrick ......................................... 10 Task 4.3 . Plastic Fillers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Task 4.4 . Activated Carbon ............................................ 13

Experimental Setup ............................................. 13 Experimental Results ............................................ 13 Futureplan .................................................... 14

Task 4.5 - Metal Matrix Composites ...................................... 16

TASK 5.0 . MARKET AND ECONOMIC ANALYSIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Concrete and Associated Applications ..................................... 18 PlasticFillers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Activated Carbon and Carbon Black . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 EconomicEvaluation .................................................. 19

APPENDIXA .............................................................. 20

APPENDIX B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

1

TECHNOLOGY TRANSFER

Michigan Technological University has signed an agreement with Mineral Resource Technology, LLC (MRT) of Atlanta, Georgia to commercialize the fly ash beneficiation technology. This agreement was finalized July 1, 1996. MRT intends to commercialize the technology through development and operation of various facilities around the country.

Other technology transfer activities included:

0

exhibiting at the American Power Conference held in Chicago, Illinois. The exhibit included photographs, handouts, and display items such as fly ash components, mullite, and fly asWalutninum composite material.

exhibiting at Waste Expo ‘96 in Las Vegas, Nevada. The exhibit included photographs, handouts, and display items such as fly ash components, mullite, and fly ash/aluminum composite material.

attending the Powder & Bulk conference in Chicago, Illinois. This provided the opportunity to review a broad spectrum of equipment used in the processing of materials with characteristics similar to fly ash. It was a tremendous benefit to be exposed to such a concentration of state-of-the-art equipment.

TASK 1.0 - TEST PLAN

This task has been completed.

TASK 2.0 - LABORATORY CHARACTERIZATION

Task 2.1 - Sample Collection

N o new samples were received this quarter. We do not expect to collect any additional samples for this project.

Task 2.2 - Material Characterimtion

To determine if there was any difference in the elemental composition of different sizes of the fly ash, elemental analysis of each individual size fraction (+65 mesh, +100, +150, +200, +270, +325, +400, and -400 mesh) for the five as-received and clean ash samples were determined. Major elements included SiO,, A1,0,, CaO, Fe,O,, MgO, MnO, Na,O, P,O,, K,O,

2

and TiO,. Graphs showing the raw data are included in Appendix A. Analysis of the samples for trace elements is continuing.

Task 2.3 - Laboratory Testing of Ash Processing Operations

Tests were conducted to establish the parameters for dry screening the ash prior to introduction into the wet beneficiation phase of the process. Initial results indicate that if an ultrasonic unit is attached to the screen, considerably greater throughput can be realized, at the same time, plugging of the screen can be nearly eliminated. Samples of as-received ash was sent to Russell-Finex and S WECO. Russell-Finex has completed the requested tests, with positive results. The tests at SWECO are not complete.

TASK 3.0 - PILOT PLANT TESTING

N o pilot plant testing directly related to the project was conducted this quarter. The Metallurgical and Materials Engineering Department conducted a Mechanics of Mill Practice class during this quarter which incorporated fly ash beneficidtion. The students conducted laboratory and pilot plant tests using a fly ash from Detroit Edison.

TASK 4.0 - PRODUCT TESTING

Activities are underway in all five subtasks.

Task 4.1 - Concrete Testing

A detailed analysis has been completed for utilizing AEP fly to replace cement in concrete manuhcturing. This analysis included characterization of as-received and cleaned ash, testing the performance of ash-cetnent-water mixtures, and determining the mechanical properties of the concrete.

Characterimtion of AEP As-received and Cleaned Ash

Table 1 details the chemical composition and physical properties of as-received and cleaned AEP ash. The LO1 value of the ash was reduced from 21.7% to 0.4% after separation. SiO, and A120, increased from 44.4% and 22.4% to 58.6% and 29.2%, respectively. CaO showed a slight increase from 0.76 to 0.85 after separation. The physical testing results indicate that the moisture content decreased from 0.25 to 0.20, and specific gravity increased from 2.13 to 2.19 after separation.

3

Table 1 Chemical composition and physical properties of as-received and cleaned AEP fly ash

Chemical As-received Cleaned ASTM C 618 Composition fly ash (%) fly ash (%) (Class F ash)

A1203 22.4 29.2

44.0

5.3

71.7

0.76

0.86

0.32

2.35

1.11

0.03

21.7

98.8

58.6

5.2

93 .O

0.85

1.11

0.42

3.16

1.33

0.09

0.40

100.4

70 (minimum)

6.0 (maximum)

Physical properties

Moisturc contcrit (9,) 0.25 0.20 3.0 (maximum)

Spccific gravily (g/cm’) 2.1 3 2.19

Size analyses were obtained with Tyler sieves for the fractions larger than 400 mesh (37 microns) and Microtrac Analyzer for the -400 mesh fraction, The results are recorded in Tables 2 and 3, respectively. From Table 2, the particle size significantly decreased after sepwation, due to the screening operation in the separation process in which the material coarser than 150 mesh was removed from the circuit. The weight fraction of cleaned ash passing 400 mesh was 70.45% in comparison to 53.83% of as-received ash passing the same size sieve. The fly ash particles passing 400 mesh were further analyzed with the Microtrac Analyzer, and the results (Table 3) indicate that there were more fine particles in the cleaned ash than in the as-received ash.

The microscopic structures of as-received and cleaned AEP fly ash were observed by scanning electron microscopy (SEM). Figure 1 shows that the as-received ash consists of amorphous and spherical particles. The amorphous particles were larger in size than the spherical particles. Energy dispersive spectroscopy (EDS) tests indicate that the amorphous particles were composed of 45-77% SO,, 1523% A1203, 3-4.5% iron oxide, and trace elements. The spherical particles were composed of 55% SiO,, 33% A1203, 1.5-3.0% iron oxide, and trace elements. Figure 2 shows that the cleaned ash was also composed of amorphous and spherical particles, but

4

the amount of amorphous particles was less and the particle size was smaller than in the as- received ash. The chemical composition for the amorphous and spherical particles in cleaned AEP ash was the same as the as-received AEP ash.

Table 2 . Particle size and distribution of as-received ash and cleaned AEP fly ash

Tyler Mcsh As-rwcivcd ash Cleaned ash

Weight % Individual 96 Cumulative % Weight 5% Individual % Cuniulativc %

+65 0.60 0.77 0.77 0.00 0.00 0.00

+loo 1.40 1.79 2.55 0.00 0.00 0.00

+I 50 4.20 5.36 7.91 0.60 1.36 1.36

+200 7.80 9.95 17.86 2.40 5.45 6.82

+270 8.00 10.2 28.06 2.80 6.36 13.1 8

+325 3.80 4.85 32.91 4 .00 9.09 22.27

+400 10.4 13.3 46.17 3.20 7.27 29.55

-400 42.2 53.8 100.0 31 .o 70.45 100.0

Table 3 Microtrac analysis of particle size distribution for AEP fly ash passing 400 mesh

Cliannei As-rcccivcd ash Cleancd ash

Cuniulativc % Volumc % Curriulativc %I Volume %

62

44

31

22

16

11

7.8

5.5

3.9

2.8

1.9

1.4

0.9

100.0

94.8

79.6

61.5

45.3

3 1 .o 20.1

11.9

6.8

3.6

0.9

0.2

0.0

5.2

15.2

18.1

16.2

14.3

10.9

8.2

5.1

3.2

2.7

0.7

0.2

0.0

99.9

95.5

83.5

68.8

54.5

40.6

28.8

19.4

12.7

7.4

2.6

0.8

0.0

4.3

12.1

14.7

14.3

13.9

1 1.8

9.4

6.6

5.4

4.8

1.7

0.8

0.0

5

Figure 1 Microstructure of as-received AEP ash

Fi-+re 2 Microstructure of cleaned AEP ash

Concrete Performance

Table 4 shows the water requirement, workability of the fresh fly ash-cement-water mixture, and compressive strength of the concrete. The water to cementitious material ratio was designed at 0.5 for Grade 35s concrete. When the as-received ash was used to replace cement, the water to cementitious material ratio increased with the amount of cement replaced by the ash in order to obtain the desired slump value. In contrast with the as-received ash, the water to

, cementitious material ratio decreased with the amount of cement replaced by the cleaned ash in order to obtain the desired slump value.

Table 4 Effects of ainount of cement replaced by AEP fly ash and curing period on concrete properties

~ ~

Concrete grade W/c" Slump Air Density Compressive strength (psi) and type ratio

in % ,,& 7 day 28 day 91 day

Grade 3 5 s 0%

8%

received ash 20%

concrete with as-

0.50

0.50

0.5 1

3.5

3.2

2.5

7.1

2.0

1.8-

148.8 3692 4676

151.2 4223 5801

149.6 3357 4582

5512

6902

620 1

30% 0.52 2.2 1.9 148.9 2420 3681 5141 ~~ ~~~~ ~~ ~~~

Grade 35s 0% 0.50 3.5 7.1 148.8 3692 4676 5512

8% concrete with cleaned

ash 20%

0.47

0.46

3.2 6.5

3.0 5.5

145.4 3263 4446

145.8 2561 3999

6025

5442

30% 0.44 3.5 6.9 144.2 2273 368 1 4659

Grade 30s 0% 0.50 2.5 7 .o 146.4 3474 4158 4399

20% 0.48 concrete

with cleaned ash 30% 0.46

4.0 7.5 145.3 2385 3186

3.3 6.0 144.4 1976 2774

4547

4076

Grade 40s 0% 0.47 4.0 5.5 148.4 3981 4823 5412

20% concrete

with cleaned ash 30%

0.43

0.4 I

5.25

4.5

9.0 142.3 2609 4020

6.0 144.2 2415 3822

5204

4953

Notc: a) W/C ralio is lhc ratio ol'walcr/(ccmcnt + fly ash). b) pcf is pourid pcr cubic yard.

7

The high water requirement of the as-received ash-cement-water mixture is mainly due to the high LO1 content in the ash because carbon particles have a porous structure which can absorb more water. By increasing the amount of cement replaced by the ash, the number of carbon particles in a unit volume increase, therefore the water requirement increases in order to obtain the desired slump. When the LO1 content is reduced by beneficiation processing, the water requirement of cleaned ash-cement-water mixture is reduced as the cleaned ash fraction increases, which improves cement workability. Differences in particle size distribution and shape between as-received and cleaned fly ash may be another factor influencing the water requirement in concrete. The high proportion of fine, smooth spherical shaped particles in the cleaned ash may improve the rheological properties of fresh concrete.

The air content in fresh cement without fly ash was 7.1%. When the as-received ash was added, the air content was reduced to 2% or less. When the LO1 content was reduced by the beneficiation process, the air content in the cleaned ash-cement-water mixture was an average 6.3% for grade 35s concrete, and an average 6.5% for grade 30s concrete. The air content in cleaned ash-cement-water mixture for grade 40s was higher than in the cement without fly ash.

All fresh concrete mixtures entrap a certain amount of air during mixing. The entrained air can improve the flow properties and workability of the fresh cement mixture. When the as- received ash was added into the mixture, the loss of air may relate to the high carbon content in the ash because of the carbon’s high specific surface area and sorption capacity. The low air content in the as-received ash-cement-water mixture increases the amount of water required for the cement to flow. I n order to keep a equal level of air in the ash-cement-water mixture as was present in the concrete without ash, the air entraining agent has to be added at a much higher dosage than usual. When the LO1 content is reduced by the beneficiation process, the air content in the cleaned ash-cement-water mixture is decreased only slightly in grade 35s concrete in comparison to concrete without fly ash.

Mechanical Properties of the Concrete

Figure 3 shows the effects of the amount of cement replaced by fly ash and the curing period on compressive strength of Grade 35s concrete. The concrete with 8% as-received ash had higher seven day compressive strength and the concrete with 20 and 30% as-received ash had lower seven day compressive strengths in comparison to the concrete without fly ash. All the concrete with cleaned ash had lower seven day compressive strength than the concrete without fly ash. The 28 day compressive strengths of both as-received and cleaned ash concrete were over 3500 psi, which satisfies the design requirement. The 91 day compressive strengths of the concrete, including both 8% and 20% as-received and 8% cleaned ash were, respectively, 6902, 6201, and 6025 psi, higher than the strength of concrete without fly ash (5512 psi). The 91 day compressive strength of the concrete with 20% cleaned ash was 5442 psi, which is nearly same as the strength of the concrete without fly ash.

8

Compared to the concrete without fly ash, the concrete with fly ash has a low early strength, with the exception of the concrete with 8% as-received fly ash. The concrete with fly ash has fast strength development from day 28 to day 91 in comparison to the concrete without fly ash. Comparing the concrete with as-received fly ash, the concrete with cleaned ash has relatively low compressive strengths for all ash levels and curing periods. The reason of this is not clear. From the microstructure of fly ash, the cleaned ash, with more fine and smooth particles, assists in the strength development of the concrete, which has been proven by previ&s studies. From the ratio of water to cementitious material, a low water requirement for the cleaned ash- cement-water mixture would improve the compressive strength of the concrete. A possible reason is the change of ash composition which affects the reaction between the cleaned ash and cement. Further studies need to be conducted to examine the surface activity and polarity of fly ash as well as any chemical reaction existing between the fly ash and cement.

7000

h .- 6000

v

a> > 3 4000 .-

2 e 3000

.... ,.,.' ,....

+ 0% .._. c::.:. ... . 8% 20% * 30% .... . . . . . . . . , , . ~.

2000 ' , < 7 28 91 7 28 91

Ctmcrctc %?th a\-rcccivcd ash Time (day) Concrctc with clcancd ash

Figure 3 Effects of amount of cement replaced by fly ash and curing period on compressive strength of concrete

Figure 4 shows compressive strengths of grades 30S, 35s and 40s concrete with and without cleaned fly ash. All the grades of concrete with cleaned ash had lower seven day compressive strengths compared to the same grades of concrete without fly ash. The 28 day compressive strengths of concrete with 20% cleaned ash tnet the design requirement for all three grades of concrete. When 30% of the cement was replaced by cleaned ash, both the grade 35s and grade 40s concrete satisfied compressive strength specifications after 28 days. The concrete

9

with clean ash had fast strength development from 28 to 91 days for all three grades in comparison to the concrete without fly ash. The 91 day compressive strength of grade 30s concrete including 20% cleaned ash was 4547 psi, which is higher than the strength of concrete without fly ash (4399 psi). The 9 1 day compressive strength of grade 35s concrete with 20% cleaned ash was 5442 psi, which is nearly the same as the strength of the concrete without fly ash (55 12 psi). The 9 1 day compressive strength of grade 40s concrete with 20% cleaned ash was 5204 psi, which is close to the strength of the concrete without fly ash (5412 psi).

6000 n .- cn a - 5000 5

2? 4000 CT) C

cn +

0 -? cn 3000 E) cn

e 2000 6

1000

tiradc 30s Gradc 35s

..... + ................ + ................ : ..............___ { _.__._..________ $ .......l.l.... 3 ____._,_____.___+.I._..__._____. + ...,.........,.. : -..-.......-.. 1 ................ J .I._.

7 28 91 7 28 91 7 28 91 Time (day)

Figurc 4. Effccls of amounl or cciiicnl replaced by clcaricd Ily ash and curing peritxi, and concrclc grade on compressive slrcnglh of concrete

Task 4.2 - Concrete BlocklBrick

The concrete block testing and analysis were completed, utilizing AEP fly to replace cement in concrete block manufacturing. The testing includes density, moisture content, absorption, and compressive strength of concrete blocks with various curing period characterization of as-received and cleaned ash. Test results are recorded in Table 5. The effects of as-received and cleaned AEP ash on the properties of concrete blocks are analyzed as follows:

Figure 5 shows the effects of fly ash type, amount of cement replaced by fly ash, and curing period on compressive strengths of concrete blocks. All the concrete with fly ash had lower compressive strengths than the concrete without fly ash throughout all the curing periods.

10

AII the concrete with cleaned ash had a lower one day compressive strength than the concrete with 20% as-received ash. The concrete with cleaned ash developed strength more rapidly from the first to the seventh day in comparison to the concrete with as-received ash. The concrete with 15% and 20% cleaned ash had higher seven day compressive strengths than the concrete with 20% as-received ash. The 28 day compressive strengths of both as-received and cleaned ash concrete met design requirement.

I

I

Table 5 Physical and mechanical properties of concrete block

Test Block properties Block Block with Cleaned ash content in period without 20% as- block

fly ash received ash 15% 20% 30%

Density (pcf ") 138.2 133.0 129.0 134.3 133.9

Moisture con tent (%) 37.8 23.8 21.4 24.3 16.8

Absorption (pcf) 7.5 7.9 9.0 7.7 7.5

1 day

compressive strength (psi) 2260 1750 1670 1380 1320 ~ ~

Density (pcf) 138.2 134.5 132.8 134.3 133.9

Moisture con tent (%) 37.8 28.1 27.8 24.3 24.6 7 day

Absorption (pct) 7.5 8.2 8.2 7.7 7.5

Compressive strength (psi) 3 1 20 2130 2790 2320 1930

Density (pci) 138.2 134.3 132.8 134.5 133.9

Moisture content (5%) 37.8 24.3 27.8 28.1 24.6 14 day

Absorption (pcf) 7.5 7.7 8.2 8.2 7.5

Compressive strength (psi) 3310 2400 2820 2520 2280

Density (pcf) 138.2 131.0 132.8 134.3 133.9

Moisture content (96) 37.8 21.4 27.8 24.3 24.6 14 day

Absorption (pcfj 7.5 9. 1 8.2 7.7 7.5

Compressive strength (psi) 3290 2270 2920 2320 2000

Note: a) Thc pcf is pound pcr cubic yard.

11

= u)

3000 5

E 2500 m

.c.r u)

-!! u) 2000 u) Q)

I500

1000 8

------w No ash

- r488&---------......

15% clcancd ash

20% clcancd ash

-.-..C..

30% clcancd ash

I..

. . . . . . . . . . . . . ,___

i i ...................... { .............................................. i ............................................. .f ............................................. .....................

1 7 14 28 Time (day)

Figure 5 Compressive strength of concrete block

Task 4.3 - Plastic Fillers

The mechanical property testing on the plastic tensile test specimens from fifteen fly ash and polymer compounds is complete. The polymer compounds tested were polypropylene, low density polyethylene, and high density polyethylene, with five loading levels of fine AEP clean ash. For comparison, five kg of commercial CaCO, filler was purchased and used to prepare compounds with the same three polymers at the same loading levels as the fly ash tests.

After the mechanical testing, selected test specimens were examined with the SEM to evaluate the bonding between the fillers and the polymers.

A local plastics company, UP Plastics of Baraga, Michigan, produced commercial automobile parts using the fly ash / polymer compounds. These trials were very successful. The fly ash polymer compounds showed no difference in the manufacturing or appearance in comparison to their currently used commercial compounds, which include a mineral filler.

12

Task 4.4 - Activated Carbon

Time/Temp . 30’ 45’ 60’ 120’ 180’

Experimental Setup

600” c 700” c 850” c 900” c 43.4 48.3 53.3 47.0 42.9 53.3 56.9 57.2 47.9 64.9 42.9 51.9

A new experimental setup has been fabricated in-house to provide better control of the activation temperature, which had been a problem in the previous experimental setup. The activation chamber is basically a steel kiln with dimensions of 4” inside diameter and 2.5” in length. Three 1/8” thick lifter bars are mounted inside the kiln wall to help mix the carbon as the kiln rotates. The inlet gas tube is located in the center of the kiln and protrudes into the kiln about 1.5 inches. The internal connection of the outlet gas tube is perforated and wrapped with copper screen to prevent carbon particles from blowing out. Figures 6 through 8 show the setup.

In each test, about 10 granis of carbon is loaded in the kiln and the kiln is placed in an electric wire furnace. This furnace is covered for heat isolation and can heat the kiln up to 1200°C. To run the test, argon gas is turned on to purge the system. This is followed by powering the furnace and starting the motor that rotates the kiln. The argon gas continues to flow though the system until the desired temperature has been reached. Then, the argon gas is switched to the desired activation gas and timing of the test begins. The argon gas is switched back on to replace the activation gas when the activation is finished and the furnace is shut down. The argon continues to flow until the furnace cools down to room temperature and the drive motor is turned off. The carbon is then unloaded from the kiln for analysis.

Experimental Results

This set of tests examined the effect of temperature and time on activation of NPC fly ash carbon, using CO, as an activation agent. Since the adjustment of CO, flow rate currently is technically difficult in our lab, it was held constant in these tests. The effect of CO, flow rate variations will be examined later when we have a proper flow meter. The flow rate of both CO, and argon were fixed at 1.8 liters per minute during the test. The carbon activation level has been evaluated by BET surface measurement and will be further evaluated by adsorption of iodine and molasses. The BET surface area after activation at different temperatures and time are summarized in Table 6,

Table 6. BET surface area (m2/g) of the carbon after activation at various temperatures and time (the surface area of the carbon was 43.8 m2/g before activation)

43.1 45.7

13

I t appears that higher temperatures and longer time favor activation at the current experimental conditions. Further tests are in progress to optimize the activation conditions. Also the LOI, Burn-off, and adsorptive properties of the activated carbon are under determination.

Future Plan

The following will be tested in the next quarter:

Optimizing activation conditions, including CO, flow rate, activation temperature and time, and carbon loading. Conducting adsorption isotherms of iodine and molasses as well as BET surface area to overall evaluate the activation. Test steam as activation agent, if possible. 3)

Figure 6. Laboratory setup for carbon activation

14

Figure 7. Closeup of the activation kiln sitting in the furnace

Figure 8 . Closeup of the activation kiln

15

Task 4.5 - Metal Matrix Composites

Work has continued on fly ash aluminum composite materials during the past quarter. Our primary goal has been to increase the mechanical strength of the material.

Originally, research was begun using a 6092 alloy. It was theorized that there was a chemical reaction with this alloy and the fly ash, which caused a deterioration in hardness and mechanical properties. Using SEMEDX, an area rich in Si was found to surround the fly ash particles. The aluminum matrix material had little or no Si in the processed matrix. The original powder blend contained 0.6 wt% Si. Therefore, it was decided to use a 2124 aluminum alloy (see Table 7) .

Table 7 - Alloy Composition

Alloy AI CU Mg Si Mn

6092 97.60 0.80 1 .OO 0.60 0.00

2124 93.50 4.40 1 .so 0.00 0.60

(wt%) (wt %) (wt %) (wt %) (wt%)

A sample of the 2 124 10 v/o fly ash alloy was examined metallopaphically. The sample was mounted in Bakelite and polished on successively finer abrasive media down to a final level of 0.3pm diamond. The sample was then etched with 0.5% HF. The sample was examined both optically arid with the scanning electron microscope (SEM). Using optical microscopy one could not sce a reaction zone around the fly ash particles in the 2124 matrix. The sample was also examined under the SEM with EDX (energy dispersive x-ray). The composition of the matrix/reinforcemetit interface zone did not appear to have an abnormal elemental distribution. A reaction zone around the fly ash particle was not present in the 2124 alloy. (see Figure 9 and Figure 1 0 below).

Figurc 9. 2 124/ 10 v/o Fly Ash ( 1 OOOX)

Figurc 10. 2124/ 10 v/o Fly Ash (200X)

16

Hardness levels of the 6092 composite matrix were not as good as hardness of the matrix material processed similarly (See Table 8). However, when the 2124 matrix alloy was used, the hardness values of the composite material were higher than that of the PM processed 6092.

Table 8 Hardness Values

Alloy 6092 60V2 10 v/o 2124 10 v/o Fly Ash Fly Ash

Hardness (RHE) 78.73 36.42 100.77

In order to increase the mechanical properties of the material it was theorized that cold pressing couId cause the lower properties. To test this hypothesis, cold isostatically pressed (CIP) %" dia. bars were produced. These bars were sintered per optimum sintering procedure. This was with a 4 hour degassing hold and a ramp to sintering temperature of 615°C and a '/2 hour hold for sintering. The bars were then machined into round tensile bars per ATSM standard E8 "Test Methods for Tension Testing of Metallic Materials.". The bars were then heat treated per our optimum procedure which was 5 13°C for 1 hour, cold water quench, and an 18 hour hold at 170°C. Heat treated round tensile specimens were tested per ATSM standard E8. The results of the mechanical testing are listed in Table 9.

Table 9. Mechanical Testing Results

Tensile Bar Composition Sinter Density Ultimate Elongation (% ) Set # (% theoretical) Strength (psi)

1 6092 1 0 v/o Fly Ash 87.7 12,393 * 7.40

2 6092 1 0 v/o Fly Ash 87.7 17,867 5.54

3 2 124 1 0 v/o Fly Ash 91.4 18,385 2.41

4 2 124 1 0 v/o Fly Ash 90.7 14,067 15.0

5 2 124 I O v/o Fly Ash 89.9 23,663 2.48

Tensile properties have improved but are still not up to the target. When examining the microstructure of the material one can see large areas of porosity. It is theorized that some of this porosity is due to poor out gassing of the adsorbed and absorbed gases in the aluminum powder particles. To test this theory, powder will be out gassed in a vacuum furnace up to 400°C and

17

then cold isostatically pressed. The CIP’ped bars will then be sintered in a vacuum furnace to aid in out gassing. This work is currently in progress.

In summation, tensile properties are improving due to a composition and consolidation change. Further work needs to be done to increase the sintering density and to decrease the porosity in the material due to residual gases adhered to the aluminum powder particles. This work is currently in progress.

TASK 5.0 - MAKKET AND ECONOMIC ANALYSIS

Ultimately the determination of a technology’s worth is made by the marketplace. Throughout this project there has been constant attention to reducing the fly ash beneficiation technology to commercial practice. This emphasis has resulted in the execution of an agreement by Mineral Resource Technology (MRT), Atlanta, Georgia to license the fly ash technology and to jointly build a fly ash cleaning system as a demonstration prototype for a full scale operation. A copy of the press release that was in the MTU weekly newsletter announcing the agreement is attached in Appendix B.

Market opportunities have been confirmed for all ash components. The value of the various markets and associated quantity demands are being reviewed to finalize theeconomics of a commercial ash cleaning system. Particular effort is being expended on the markets for the recovered carbon because of the known relatively high value represented by this fraction of the ash.

During a recent nieeting with MRT, a work plan was developed that included finalizing target market opportunities. The highlights of the plan relative to Task 5.0 are reviewed below.

Concrete and Associated Applications

Concrete block making trials were successfully completed at Alpena Community College. The College has a worldwide reputation in cement and cement products. Their Besser Center is supported by a leading block equipment manufacturer and LaFarge Cement Company. Both firms are leaders in their respective industries.

The focus o f the current project has been on the development of high value, high volume markets for the recovered fractions of beneficiated fly ash. Thus, the markets associated with fundamental uses of fly ash components, such as cement replacement, construction, and lightweight aggregate, have been assumed to exist with sufficient demand to utilize outputs from a commercial fly ash beneficiation system. This line of reasoning has been confirmed to be correct by MRT, based on 27 years of fly ash experience represented by their staff.

18

Plastic Fillers

The potential for this market has been confirmed by R. J. Marshall Company and they are prepared to assist in the marketing of cleaned ash for this application. Laboratory results discussed elsewhere in this report confirm fly ash filled plastics have adequate strength and molding characteristics when compared to normally used fillers such as calcium carbonate.

Activated Carbon and Carbon Black

The release of a long awaited EPA report on mercury emissions from coal burning electric utilities has been further delayed until next year. Rather than base the use of fly ash recovered carbon on mercury control, marketing efforts have shifted to emphasize other environmental applications such as odor control and rubber compounding.

Agriculture wastes from feedlots and swine raising are particularly odorous and opportunities may exist t o use fly ash carbon as an odor control agent. The literature confirms there is a need for odor control in these applications and that carbon may be the basis of a viable odor control system.

Previous investigations by MRT indicated recovered carbon is useful in rubber compounding. This information, however, needs to be updated in terms of market demand and pricing.

Economic Evaluation

Having signed an agreement with MRT that will allow for the commercialization of the ash beneficiation technology, efforts have shifted to addressing the scaling up of the process to a full size industrial operation. Both capital and operating cost estimates were revised to better suit the production levels proposed by MRT.

I n addition to the primary components used in the wet phase of the process, attention was also given to those components required to properly handle the bulk material. Information was requested from various companies involved in the manufacturing of trailers for use in the mobile transport of ash, pneumatic transport systems, storage silos, and bins that would be required to properly handle the bulk solids. This allowed for the expansion and revision of the flow sheet and further refinement of the costs that would be associated with a complete plant.

19

APPENDIX A

Task 2.2 - Material Characteriration

Major Elemental Analysis by Size

20

-- AEP as Received

Size Fraction

BGE as Received 70 60

10

O +65 +I00 +150'+200 +270 +325 +a -400 Size Fraction

10 0

70 .......... CPC .- ......... as r. Received - ~-

Sire Fraction .........

, x 70 ~..- DE#2 __.-_...-.-,--....T as Received -

. I j .............. &.. .......... .c.. ........ :. ...... ;

NPC as Received

+65 +lo0 +I50 +200 +270 +325 +400 40- Si Fraction

-- AEP as Received

+65 +lo0 +la +200 +270 +325 +# i-' Si Fraction

70 ... BGE . as Received .... ... . . _____

- - I - I O 4 ; - 0 -

+65 +100+150+200+270+325+400 -400 Sire Fraction

CPC as - Received _ _ - I

i 70 - - - .- 60

i .-i ....... _._ . . -. 4. ...... 2-. -.- ........ L-_ .... , , . I .......... - ... .* .... .................

1 ..-L ..... - .. . . I . _ ._ ....... ............ .... i.- - .. ....... __. .. '... ..-, -. : . I

8% am 8;

+65 +100+150+200+270+325+400 400 Si Fraction

---Si02 -=-A1203 - Fe203 MgO - MnO

DE#2 as Received

NPC as Received

+65 +la +150 +2(10 +270 +325 +400 -400

+Si02 +AI203 ---Fern3 b@O * MnO *N&O . F205 ---DO +CaO +Ti02

si Fraction

-_ AEP Clean ....

..

.... .....

...

Size Fraction

Size Fraction

-

70 ...

60 50

$40 830 20 10 0

She Fraction

70 60 50

;P

0

040 %30

20

10

0

Size Fraction

AEP Clean

+65 +lo0 +150 +200 +270 +325 +400 -400 S i F d o n

-+-Si02 -A1203--Fe203 MgO MnO

4-m P205-K20 +-cao -=-Ti02

~ -

BGE Clean

+65 +lo0 +150 +200 +270 +325 +400 -400 SiFraction

-- CPC Clean .~. : . . . . . . . L ..... : ............ ! f

10 ~ ~

60 .... .; ....... .i... .- -:.. . ..... -1 _ _ L j ....

50 ..... j -_._; :~ - . . .- - , . ..................... .- .........

-..- . A A. .... l-. - .a , , .-. ............. ;....-.-A ...... : i & : ........ ;- . -;.. .. -i ...... ;.. -..i ........ i ....... L , . I , : , : ,

. . ..... .... i. ......

... .... ..

Sire Fraction +Si02 +A1203+-Fe203 MgO -=-MnO

+ N a M .: p205 ~ K 2 0 -5-ca0 ---no2 ~ -

+65 +I00 +I50 +200 +270 +325 +400 -400

APPENDIX B

MI’U / MRT Licensing Agreement Press Release

21

*

v, u 0

r U u

July 12,1996

Be thankful for your problems. If they were less difficuk someone wirh less

ability might have your job.

--Bin & Fieces

Vol. >001111, No. 45

MTU signs licensing agreement on fly-ash technology - . America's electric-utility smokestacks trap about

50 million tons of fly ash every year, and there hasn't been a whole lot done with it.

Until now. A licensing agreement recently exe- cuted between Michigan Tech and Mineral Resource Technologies (MRT) of Atlanta could make fly ash the latest natural resource of the industrial age, as well as garner the University millions of dollars in royalties over the next several years.

Jim Hwang, director of the lnstitute of Materials Processing (IMP) has spent the last ten years studying fly ash, so named because it flies up chimneys (and is trapped in filters) instead of settling on the bottom (like the aptly named bottom ash). Hwang may be the sooty byproduct's biggest booster, envisioning it as a source of products ranging from activated charcoal to plastics filler.

His vision had not moved to market, however. Traditionally, fly ash had either been disposed of in landfills or used as a substitute for cement in con- crete. Industry had no incentive to do much more.

Incentive has now been provided in the form of federal Clean Air regulations. New rules designed to curb acid rain require coal-fired power plants- among the largest fly-ash producers-to reengineer their furnaces. A side effect has been a huge increase in the amount of carbon in the fly ash and a lot more fly ash in general.

High-carbon fly ash makes for pretty sad concrete-it cracks, it's hard to work with, and it looks bad, Hwang said. And just as the electric- power industry was watching its single market for fly ash wither, it was faced with a lot more of the stuff to get rid of.

ribbon. Waiting in the wings have been Hwang, IMP, and Michigan Tech, who recently signed an agreement with MRT (a subsidiary of Phillips Brothers Chemicals headquartered in Fort Lee, New Jersey, the nation's largest manufacturer of specialty chemicals) to commercialize the recovery and processing of fly ash. MRT intends to develop and operate facilities across the country that are designed to remove carbon from the fly ash.

Together, the lnstitute of Materials Processing and MRT plan to build a fly-ash cleaning system as a prototype for a full-scale plant. The plant will be ,built a t one of the myriad coal-fired generating plants east of the Mississippi; about 40-60 sites are in the running. The system will include Hwang's patented processes, which separate out fly ash's component parts: carbon, iron oxide, and cenophore+a low-density form of silicate.

In addition, MRT will pursue new markets for the cleaned-up ash, primarily as a replacement for cement, as well as filler for opaque plastics such as WC, for ceramic insulators and liners, and for metal composites.

"It could be in everything from golf balls to satellite dishes," Hwang said.

"The MTU scientists have made an important achievement in advancing and patenting this new carbon recovery technology, " said MRT President

But one person's red tape is another's Christmas

Hugh Stiannonhouse. " MRT is extremelyexcited to.:; bring this technology to the marketplace because it ; will allow us to effectively transform coal ash from a : waste byproduct that is landfilled into a mineral filler: product that can be recycled into concrete and otheci products, thereby reducing the solid waste stream and utilizing a valuable natural resource." ''

The licensing agreement is expected to generate : millions in royalties to Michigan Tech, according to . Sandy Gayk, director of intellectual properties and trademark licensing, who was instrumental in successfully negotiating the agreement.

"We are extremely pleased to have established a long-term partnership with MRT," she said. "They have the ability to commercialize this and future fly ash technology, and that is a key element in this agreement."

Hwang believes this technology is the vanguard of a new brand of mining-the processing of industrial byproducts to form new materials.

"In the past, most of our raw materials were basically mined from natural resources,' he said. "In doing this, we disturbed the Earth, and we were not looking at total efficiency. This technology will reduce the dependence on mining and will lead to a new generation of materials supplies."

Why everybody's happy "This is a prime example of what IMP is doing,"

President Curt Tompkins said at the signing ceremony kicking off MTU's technology transfer agreement with Mineral Resource Technologies (MRT). "It's significant that a company located in Houston and Atlanta has proven one of IMP'S premises-that if we're answering the needs of industry, we'll link up with industry."

is a many-win situation for all participants. The agreement to commercialize fly-ash recovery

For Michigan Tech, the potential seven-figure revenue stream could support programs throughout the University and promote other ties with industry. The leading-edge technology positions MRT at the forefront of a brand-new industry. Revenues could support IMP Director Jim Hwang's continuing research ioto fly ash, which he describes as "more and more interesting" even after ten years of study. The recovery and processing technology should keep millions of tons of fly ash from filling up the nation's landfills, at a cost savings to electric utilities. The process will provide clean fill for concrete, as well as numerous compounds of use to industry. The activated charcoal fraction of fly ash is especially promising, according to Hwang, and could help solve other environmental problems in the future. Once in force, the process will eliminate a long- standing disposal problem in the coal-burning industry, making coal a more-viable fuel.

Public Safety has moved to Wadsworth Public Safety has moved its offices from Administration/Student Services to the roomier west end of

Wadsworth Hall, in the former Health Center area. If you plan to drive there, they recommend that you park across the street in the visitors' lot behind Hamar House (Counseling Services).