Dunkirk Maryland Diatomit - der Sammelthread

[anne]

Hallo zusammen,
ich habe gestern die Proben verschickt. Manch einer hat diese heute schon erhalten.
Daher möchte ich diesen Thread starten, in dem wir uns austauschen können zur Reinigung, zu den Ergebnissen, zur Bestimmung usw.
Bill Dailey hat sich hier angemeldet, darüber freue ich mich besonders und wird uns sicherlich mit seiner Erfahrung unterstützen.
Ich hänge hier ein Bild des Rohmaterials an. Wer die Möglichkeit hat, es sich unter dem Stereomikroskop anzuschauen, sollte das machen. Man sieht dann die Diatomeen schon wunderschön.
Ich habe noch 3 pdf´s angehängt, die Bill Dailey gefunden hat, die sich auf seien Probe beziehen.
Er hatte mir geschrieben, dass keine kalkhaltigen Bestandteile zu erwarten sind, daher könnte auf Salzsäure verzichtet werden.
Sicherlich klinkt er sich bald hier ein.
Viel Spass an alle mit dieser tollen Probe!
lg
anne

[Michael K.]

Hallo anne,

Ist ja schön zu hören das sich Bill Dailey hier angemeldet hat.
Das scheint ja ebenfalls sehr pudriges Material, ähnlich wie aus Palos Verdes zu sein. Von der ich nach wie vor immer noch
begeistert bin. Das entfernen der störenden Nadeln geht nur durch häufiges Dekantieren. Ich giesse das Wasser ab wenn nur noch
Nadeln im Wasser schweben.
Nun den den Thread, werde ich natürlich verfolgen.

LG
Michael

[Fraenzel]

Hallo Anne,
herzlichen Dank für den Brief mit dem Diatomit. Du schreibst, daß evtl. eine Reinigung mit HCl nicht notwendig sei. Das höre ich sehr gerne. Ich freue mich schon sehr, diese Diatomeen im Mikroskop betrachten zu können.
Beste Grüße
Peter

[bill2penn]

Hello everyone,
I am very excited to be part of this discussion. My understanding of the German language is very poor so I use Google Translate to read the posts.

Usually I use my "standard" diatomite cleaning method when I clean Dunkirk diatomite (hot conc. HCl, then hot conc. H2SO4 with KClO4, then soap and mild base. This also includes all the many water washes and settling of the forms in between each step). I am currently experimenting with methods that do not require harsh chemicals so that more people will be comfortable cleaning this material using common household materials such as baking soda, white vinegar, and liquid dishwashing soap.

This is what I have done so far:

1. I did the freeze/thaw multiple times to make "mud" of the diatomite. I did this by placing some diatomite in a zip-lock plastic sandwich bag with enough water to completely cover the diatomite. Then freeze in freezer. Remove and let thaw. Repeat many times until only "mud" without any pieces is formed. If you find pieces of plant roots or other foreign objects in the material you can just pick them out as you are able.

2. I add mud to a beaker with water and heated to boiling. I used about 500mL of water with maybe 30 mL of "mud". Once boiling, I carefully added 0.5 teaspoon of baking soda (sodium bicarbonate). This foams a little since some of the sodium bicarbonate is converted to sodium carbonate by heating. This solution acts as a mild base. Continue heating the mixture for 2 or 3 hours. Then stop heating, dilute with water and let the mixture settle for 2 hours. Carefully decant most of the water over a period of 30-60 seconds so the solid on the bottom does not pour out. Then add more fresh water, let the mixture settle again for 2 hours, and carefully pour off liquid again. Repeat until the liquid that you pour off does not look cloudy after two hours.

3. I add about 500 mL of water and several large drops of liquid dishwashing soap (I am using Dawn Dishwashing liquid) and return the mixture to heating. If there is not much foam that forms I add a few more drops of the liquid dishwashing soap. Continue heating the mixture for several hours. Then dilute with water, let the mixture settle for a couple hours, and carefully pour off the liquid over a period of 30-60 seconds so the solid on the bottom does not pour out. Add fresh water, let the mixture settle for a couple hours, and carefully pour off liquid again. Repeat until the liquid that you pour off does not look cloudy after two hours.

This is as far as I've gotten my experiment so far but I can tell from experience that this is cleaning the forms. I will add to this as I can.

I am happy to try to answer questions.

Best regards to all diatomists,
Bill Dailey

[Carsten Wieczorrek]

Hello,
as  Bill follows us here I try to write in english.

I received my sample today. First I separated the powdry part from the big solid parts. The powder was cooked in 20% HCl. And yes, there is no CO2 development. But after cooking the liquid becomes light yellow, so there is some iron diluted.

The big parts are now on my freeze-machine. It is not my invention, it is somewhere here in the forum but I can not find the link. It consists of a big, strong peltier-element that can freeze samples up to 5 g down to -20°C. It is mounted on top of a big active CPU cooler and a power supply from an old halogen lamp. As a "switch" I use a simple mechanic timer clock. It has four switching steps per hour, so I can freeze the sample 48 times per day down to -20°C and warm it up to room temperature 48 times per day. Usually one day is enough to get a soft mud.

So, now I have to go in my cellar to remove/decant the HCl solution from the first sample and wash with destilled water. I hope I can do the H2SO4 step tomorrow evening. As oyxidizer I will take hydrogenperoxid.
I report tomorrow,
schöne Grüße
Carsten

[Beatsy]

Hi Bill,

your experimental cleaning protocol for diatomite is extremely interesting. I have long hated doing the last-stage "shock" with NaOH (usually several cycles) because of the danger of dissolving diatoms. If boiling in dish soap or any mild base (maybe SDS solution?) can be as effective then you have removed one of the worst, scariest and most time-consuming parts of cleaning for me. I have a mystery material going through freeze/thaw right now and will try this protocol with it for sure. Thanks very much for posting. Very thought-provoking.

Also, the "illegality" of possessing concentrated acids and oxidisers since new anti-terrorist laws were introduced has seriously complicated things for me. I used the same protocol as you - but can't do that anymore. Not legally anyway. I believe boiling conc. H2SO4 will always remain the best option for thoroughly cleaning fresh material, with 35% H2O2 perhaps the second best - but being able to use such benign chemicals for fossil material is very welcome indeed as the "illegal" chemicals can then be saved for situations where they are most needed - not that I have any, of course...

Thanks again.

[Carsten Wieczorrek]

Hello again,
two short points:
a) I stopped my freezing machine. The sample is down to mud.
b) @Bill: I know about the problems with some chemicals, but I am chemist.
Grüße
Carsten

[bill2penn]

Here in the USA we can easily get gallons of concentrated HCl (Muriatic Acid) which is used as a cleaner for concrete patios. Concentrated sulfuric acid is available as a drain cleaner (Rooto Professional Drain cleaner). Nitric acid is harder to get but you can buy sodium nitrate as a Tree Stump Remover and make your own nitric acid with sulfuric acid.
Bill

[anne]

Dear Bill,
thank you for your experiments to find a method for us "poor" Europeans without using harsh chemicals. This will allow many more people to clean the sample.
Personally, I always use H2O2 in a mildly alkaline environment to clean fossil samples. But even this is no longer legally available in Germany.
I have now sent the sample to more than 20 people and hope for a lot of feedback.
I recommend deepl.com as a translator. The translations are much better/natural than from google.


best
anne

[anne]

Hallo alle zusammen,
ich füge hier noch 2 Bilder als "Appetitanreger" bei, um die zu erwartende Vielfalt der Probe zu zeigen:
lg
anne

[bill2penn]

I thank Dr. Ralf Nötzel for sending me the Nottingham type plate and key some 20 years ago.

You may also be interested in seeing SEM images and commentary about some of the forms found in the Dunkirk sample which was recently published in Micscape magazine. You can find it here:
http://www.microscopy-uk.org.uk/mag/artfeb23/Dunkirk-diatoms/dunkirk-index.htm

Bill

[Carsten Wieczorrek]

Hello,
ok, next report.

I cooked the cleaned and dryed HCl sample in 96% H2SO4 for 5 minutes. The color changes to a light brown: the sample does not contain much organic "waste". I added hydrogenperoxid drop by drop until the sample/acid changes to white.
I washed out the acid in three steps with destilled water. Then I cooked the sample in water with 1 g Na2CO3. After 5 minutes I added some drops of liquid laundry detergent.
As I am not interested in very small diatoms I flushed the hot alcalic sample onto a 30 µm sieve and washed directly under the water tap. Then I washed with destilled water and flushes the residue with destilled water by a pipette from the sieve into a sample flask.
I did a first view on this sample, "mounted" just in water:
- very clean
- very much big diatoms
- most of them are undamaged
- many different species
I would say: the best diatomit I ever worked with. I think, I can present first fotos from mounted species tomorrow.
Good night
Carsten

[JaRo]

Moin,
auch von mir nochmal in diesem Thread eine Typenplatte und ein Kreispräparat mit Material aus Dunkirk, Maryland. Ist zwar aus einer anderen Probe entstanden, die ich vor langer Zeit bekommen habe, sollte aber von den Formen her recht ähnlich sein. Ich habe bei weitem nicht alle alle Formen gefunden, die Möller gefunden hat (von dem die Typenplatte in Annes Fotos stammt), allerdings will ich auch nicht wissen, wie viele Streu-Objektträger er für das Präparat durchsucht hat. Schon bei mir sind einige Formen sehr selten gewesen...
Viele Grüße
Jan

[bill2penn]

Very nice Jan!
I tried to attach a couple images of type slides prepared by Klaus Kemp of Dunkirk material but I can't seem to do it. I keep getting errors.
Bill

[Jakob_Wittmann]

Very nice Jan!
I tried to attach a couple images of type slides prepared by Klaus Kemp of Dunkirk material but I can't seem to do it. I keep getting errors.
Bill

Hi Bill,

it's great that you have found your way to this round!

A warm welcome!

I have created some screenshots with comments for you, which might help you when attaching pictures using the German-language user interface here.

Almost forgotten :-) :
If you have more than one file, you have to click on the "(mehr Dateianhänge)" field.



Best regards until soon

Jakob