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Toxics Use Reduction Institute · Surface Solutions Laboratory
 
Toxics Use Reduction Institute




Surface Solutions Laboratory

Trial Report



Trial Number 0

(Client Number 32, Project Number 1)

Trial Purpose: Testing on the asphalt coated core windings

Date Run: 09/19/96

Experiment Procedure:
I just finished up some testing on the asphalt coated core windings that you sent me last week. I am glad to say it looks like I found two semi-aqueous chemicals that could possibly be effective for your cleaning operations. The two chemistries are AG Environmental Soy Gold 2000 and Calgon Corporation Geo-Guard 5210.
Soy Gold 2000 is a soy-derived Methyl Ester that is coupled with a surfactant to form an emulsion in water. The flash point is over 300 oF and from the testing performed, it looks like one gallon of full strength Soy Gold 2000 will dissolve 2 lbs. of asphalt.
Calgon Geo-Guard 5210 is a pine derived terpene that is also coupled with a surfactant to form an emulsion in water. The flash point is 210 oF and the Geo-Guard 5210 will also dissolve 2 lbs. of asphalt per gallon of solution (but it needs to be heated up to 160 F).
The testing performed and the actual data is shown on the following test report. I also included MSDS's of both the Geo-Guard 5210 and the Soy Gold 2000 for your perusal.

Testing plan for evaluation of cleaning chemical used for asphalt removal. I just wrote up a testing plan to evaluate several different cleaning chemicals in removing hardened asphalt off of the aluminum/copper core windings.
I am planning to break up the testing into three phases. Each phase will build upon the other, so changes in the testing plan may take place due to results obtained in the previous phase.

Phase 1-Preliminary test- Place a small piece of asphalt in a sample of each cleaning chemical. Let the sample sit for an hour and observe any solvency or softening of the asphalt. Chemicals that are ineffective will not be tested further.
Phase 2-Solvency test-Using 10 ml samples of each chemical that passed test #1, determine the maximum solvency (mg/ml) of each chemical at four temperatures (Ambient, 100 F 130 F and 160 F). For each chemical make a plot of solvency verses temperature and fit this graph with a curve. Obtain the same solvency curve for a chemical that is readily known to dissolve asphalt and compare.

Phase 3-Recycling- Spent cleaning fluid will need to be disposed of as a hazardous waste. From my preliminary observations it appears that the asphalt will foul up the cleaning solution pretty fast. This will lead to high chemical and hazardous waste disposal costs. After Phase 2 is complete, a recycling issues will be more closely thought out.

If there is anything further you would like me to take a look at, don't hesitate to call. I'll send you weekly summaries as to the progress of the testing.

Trial Results
DATE: September 18th, 1996
EXPERIMENTER: Jay Jankauskas
CLIENT:  Recycling Company
SUBSTRATE MATERIAL: Copper Aluminum core windings
CONTAMINANTS: Owens-Corning Petroleum Asphalt
CONTAMINATING PROCESS USED: As recieved from Recycling Company.

The purpose of this trial is to find a cleaning chemical for Recycling Company that will meet the following requirements.

1) Must be able to effectively remove hardened asphalt from aluminum-copper core windings. 
2) Must be able to be used effectively in a Graymills Tempest TL-2 Jet Spray Parts cleaner.  This will involve having a flashpoint below 200 F and
being compatable with the seals and gaskets used by Graymills.

In order to meet the above requirements, the testing was split up into two phases.  The first phase involved a visual examination of twelve chemicals
that were deemed to be sucessful in asphalt removal.  The second phase tested the good performing chemicals of the first phase further by evaluating
their solvencies as related to temperature.

Phase I testing:
Twelve different chemicals were tested to a visual determination as to how well they dissolved the hardened asphalt.  20 ml of each chemistry was
placed in a vial along with 2 grams of asphalt.  The vials were allowed to sit for an hour and then shaken.  The chemicals were based on a visual
amount of how well they dissolved the asphalt.  If the resulting solution was black, this showed that the chemical was effective and was tested
further.  Solutions that were colored brown or clear, were considered ineffective and were not tested further.  The results from the first phase of
testing are shown in Table 1.

Phase II testing:
The five sucessful chemistries in phase 1 were tested further by evaluating their solvencies of asphalt at different temperatures.  40 ml of each of
the five chemicals were placed in a vial with five grams of asphalt.  The vials were allowed to sit for one hour and then shaken up and 5 ml of
resulting solution was pipetted and placed in an aluminum weighing dish.  The weighing dish was then placed on a hot plate where all of the chemical
was evaporated out.  After evaporation, the resuling asphalt was allowed to cool down for 15 minutes.  The solvency was determined by equation 1:

Solubility(g/l) ={1000 * (W sub 3 - W sub 1)} over {(W sub 2 - W sub 3)/SG sub {solvent}}

Where W1 = Mass of empty weigh dish (grams)
W2 = Mass of weigh dish and solvent before evaporation (grams)
W3 = Mass of weigh dish after evaporation (grams)
SG = Specific gravity of the cleaning chemical (taken from MSDS sheets)

The above procedure was performed for four different temperatures (70F, 100F, 130F, 160F).  After plotting, each data series was fitted with a linear
regression to get a straight line fit.  The results from phase II are shown in Table II.

Phase II-
TABLE 2: Solvency Results from Phase II testing (grams/l).
Temp   Resineater    Soy Gold 2000  Soy Gold 1000  Citra-Safe   Geo-Guard 5210                     
70        11.87                                                               54.52          51.29
100      19.68            266.39                334.12             98.69           77.30
130      32.74            277.58                275.34           149.10         172.78
160      63.16            242.54                411.60           145.65          292.55

Summary:
The first part of this test was the same as phase two testing in the first test.  All of the new chemistries were tested by estimating the maximum
solvency of each chemical at various temperatures.  One of the problems with the last bunch of tests was that the solvency was the main method used
for determining the effectiveness of each chemical, in all actuality, this will just measure how long the chemicals will work for and not take into
consideration the time for cleaning.  
This time a Milton Roy Spectrophotometer (Model 21) was used to measure concentration at a wavelength of 540 nm.  This method was chosen over the
evaporation method since it was believed that non-volatiles in the solvents were increasing concentration readings.  Calibration curves were made up
for the five solvents tested by taking % transmittance readings on several known concentrations.  This data was then fit to a straight line and an
equation was obtained to relate concentration to % transmittance.  Highly concentrated samples had to be diluted with pure solvent to obtain a
readable sample (highly concentrated samples are so thick that light will not pass through).  When this was the case, the concentration obtained was
multiplied by the dilution factor (volume of pure solvent plus one divided by the volume of  asphalt/solvent mixture). 
The above procedure was performed for four different temperatures (70 F, 100 F, 130 F).  For an ideal solvent, the plot of the natural log of the
concentration verses the inverse of the absolute temperature should yield a straight line.  With this straight line fit an equation can be obtained to
relate the maximum solvency verses the temperature.  maximum concentration readings are shown in Table 1 and Figure 1.  The resulting solvency
equations are shown in equations 1 through 5.  

Table 1: Maximum Solvency Results (grams/l)
Temp (F)  AG Env. Soy    Brulin Corp.        A.W. Chest       U.S. Polychem  Rochester Midland
                Gold 1000        Nature Sol 100  Supersolv 278   Solvent 86B      Neugenic 4176
70             24.201             66.299               39.336              111.032            79.003
100           28.488             79.930               54.445              119.532            83.679
130           39.274             74.842               67.613              121.030            83.483
160            51.998            91.520               67.802              123.071            85.635

Figure 1: Vant?Hoff Solubility Curves 

Solvency Equations and linear fit errors (R2):
Soy Gold 1000   ln(C) = -1578.1 + 8.5018  R2 = 0.973     (1)
                                         T
278 Super Solv  ln(C) =-1141.6 + 7.6148   R2 = 0.8952   (2)
                                          T

Nature-Sol          ln(C) =-545.9 + 6.0685     R2 = 0.7468   (3)
                                         T
Neugenic4176    ln(C) =-147.25 + 4.8808   R2 = 0.839     (4)
                                          T
Solvent 87RB     ln(C) =-198.39 + 5.3994    R2 =0.973      (5)
                                          T 
* C= Saturation Concentration (g/l)
  T= Absolute Temperature (R or K)

Conclusions:
From the solubility tests, it appears that the U.S. Polychem Solvent 87RB has the best solvency.  Basically the higher the solvency, the less solvent
would be consumed.  By using the above equations at the desired temperature of operation and estimating the amount of asphalt that will be removed in
a given time period, the total amount of solvent used can be estimated, and taking the cost of each solvent into account, the economic optimum can
also be determined.

Solvency Rate Testing:
Although the maximum solvency will give an idea into the amount of chemical needed it still does not take into account the rate of chemical attack on
the solvent.  The rate of solvency is dictated by a variable called the diffusion rate.  Although these diffusion rates are very difficult to estimate
for a solid liquid system, a relative comparison can be obtained.
Asphalt from the customer?s parts was melted and evenly spread on 1" x 2" sample coupons.  These coupons were immersed in a 100 ml sample of the
chemical at ambient temperature.  Every ten minutes, the sample coupon was removed from the chemical bath, the solution was stirred and a sample was
taken and tested for the concentration.  The sample coupon was then immersed into the chemical bath and the above process was repeated.  Concentration
reading were taken for ten minute intervals up to 50 minutes. The results for the solvency rate testing is shown in Table 2 and Figure 2.
Table 2: Solvency Rates  
Time  AG Env. Soy   A.W. Chest       Brulin Corp.        Rochester Midland  U.S. Polychem
 min     Gold 1000     Supersolv 278   Nature Sol 100  Neugenic 4176       Solvent 86B
10       69.42             140.92              6877.3                135.41                    10085
20     107.99             207.13              4649.8                200.88                    17147
30     147.66             280.12              6534.6                263.23                    19007
40     176.31             365.15              6571.3                318.57                    19007
50     228.65             481.02              6602.7                387.94                    19007

Conclusion:  From the above testing it appears that both the Nature-Sol 100 and the Solvent 87RB were the fastest acting chemicals by far.  One thing
to note is that both the Solvent 87RB and the Nature Sol 100 dissolved all of the asphalt off the sample coupon (about 1/8" thick).

Summary:    From the above testing, it looks like the customer has two possible options:
Figure 2: Solvency Rates 
*Note: Nature-Sol 100 and Solvent 87RB results were divided by ten so that all chemicals could be viewed on the same graph.
1)  If just a single cleaning stage is desired, the 278 Supersolv and the Neugenic 4176 has a greater solvency and are faster acting than the AG
Environmental Soy Gold 1000, so they can be safely used. The Supersolv 278 has a flashpoint of  225 F while the Neugenic 4176 has a flashpoint of 235
F.   
2)  If just the spray washer may not be effective, an ambient presoak with a more aggressive chemical would definitely increase the cleaning
efficiency.  Both the Brulin Nature-Sol 100 and the U.S. Polychem Solvent 87RB would make excellent soak cleaners.  These solutions could not be
heated up that much due to their flashpoints (Nature-Sol 100 = 140 F and Solvent 87RB = 100 F).  U.S. Polychem also has a chemical similar to the
Solvent 87RB that has a flash point around 140 F.  
Both Brulin and U.S. Polychem supplied a spray wash chemical to be used in conjunction with their pre-soak solvents.  Brulin?s Chemistry was the 1990
GD, which was not that effective in the spray stage.  U.S. Polychem?s Hydropurge 007 spray cleaner definitely is more effective than the 1990 GD but
will not outperform Soy Gold 1000, Neugenic 4176 or 278 Super Solv on a one-on-one basis.  But the two chemical package supplied by U.S. Polychem was
the most effective tested out in the lab.

Table 3: Contact Names and Numbers
Company Name-Contact Name--Phone Number
AG Environmental-Tony Tompson--1-800-599-9209
AW Chesterton-Sandra Pomer--1-508-469-6698
Rochester Midland-Jim Hayden--1-508-520-1070
US Polychem-Mark Paull---800-431-2072
Brulin Corp.-Joe Titus--1-800-776-7149 x4990 Mailbox #1022


Success Rating
Final Report.

Conclusion
Based on the performance of the above tested chemistries, it looks like the two that are most likely to be effective for Recycling Company would be either the Soy Gold 2000 or the Calgon Geo-Guard 5210.
Although the Soy Gold 1000 had better solvency than any other chemical tested, it is not water soluble, so two rinses would be needed. The first would contain a slight amount of detergent, the second would be water. This would involve unnecessarily creating twice as much wastewater.
The Soy Gold 2000 has the advantage of having a high solvency at low temperatures. One potential problem I see coming from the Soy Gold 2000 is that it has a high viscosity (4.5 centipoise at 25 F). The high viscosity will definitely result in a loss of outlet pressure from the spray nozzle heads (to reduce this, you might want to run at a higher temperature).
The Calgon Geo-Guard 5210 had good solvency, but only when heated at high temperatures (you would probably want to got to at least 150 F). The Geo-Guard 5210 also has a lower flashpoint (210 F) which may be a problem at the elevated temperatures.
Although both of these chemicals are water emulsifiable, I would not recommend dilution. Usually when a solvent is emulsified, it?s solubility decreases exponentially.