Calcite: lots in grease, little in oil?

[Extreme-Duty]

Calcium sulfonate greases are loved because of their inherent EP and AW properties owed to the calcite particles. In lube oils, Ca levels are much lower and little of it seems to be in form of crystalline CaCO3.

If calcite leaves everything else in the dust, how come it is not used a lot more in non engine oils to make other additives redundant? Solubility cannot be the only issue, can it?

 

[MolaKule]

See these two white papers because I am not sure what your question is?

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=729336#Post729336


http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=729025#Post729025

 

[Extreme-Duty]

Mola,

I value ALL your white papers on here, they have taught me a lot of basics over the years. What I seem to miss in the above ones is indeed something about calcium sulfonate thickeners. This has me thinking that you consider them "regular" calcium soaps while these articles tell me they are "special" and do not need common Zn/P/S addtives to provide high levels of EP/AW properties.

Lubrizol - Calcium Sulfonate Grease Formulation

Machinery Lubrication - Understanding Calcium Sulfonate Thickeners

So, if calcite is all that is really needed for EP/AW performance, I HAVE to ask you why calcite is not being dispersed into lube oils of any kind?

 

[MolaKule]

My articles give basic information on greases and since that time, new greases and grease making methods have been developed. I also discussed Complex greases as well.

Calcite is NOT all that is needed in ALL applications.

Thickening can be done by a number of methods including gelling or adding high molecular weight polymers.

In slide 21 of the Lubrizol presentation, you will see you can add other AW/EP additives for increased load protection:

Calcium Sulfonate Grease to Meet NLGI GC-LB
•Base grease was additized with
–Zinc/sulfur/phosphorus package
–Anti-oxidant
–Anti-fretting wear additive
•Then thoroughly mixed and de-aerated

Quote:
So, if calcite is all that is really needed for EP/AW performance, I HAVE to ask you why calcite is not being dispersed into lube oils of any kind?


Oil soluble calcium sufonate detergents have the Calcium Carbonate molecule in the form of 125 Angstrom micelles.

 

[Tempest]

Quote:
So, if calcite is all that is really needed for EP/AW performance, I HAVE to ask you why calcite is not being dispersed into lube oils of any kind?

Be aware that the amount of calcium that can be included in greases is much higher than can be added to a liquid lube.

 

[Extreme-Duty]

Nothing wrong with your writings, Mola! I realize that Ca sulfonate greases were not that off the shell available ten years ago. By now, they continue to be fairly uncommon in Europe.

Just to stretch your patience I would like you to look at Lubrizol's slide 16, "Typical Calcium Sulfonate Grease Properties Without additional additives" and at:

SKF LGHB 2

Notice, it says "This grease contains no additives and the extreme pressure properties arise from the soap structure."

So, these greases can do a lot even without Zn/P/S. IMO, the absence of strong EP additives is "nice" in applications where undesired surface reaction and fatigue are of concern. What that means on the bottom line and whether other thickeners shall be banned from such applications is nothing I want to decide!

From what I understand, the CaCO3 micelles in the detergent are a lot smaller than those in the gelled Ca sulfonate grease. And as Tempest pointed out, the grease has a much higher concentration of them.

The real question is, why not make a "Ca-sulfonate-grease-like oil" (minus the thickening effect)?

A farmkid in his late 20's feels a need to close this "gap". Please help him.

 

[MolaKule]

Quote:
The real question is, why not make a "Ca-sulfonate-grease-like oil" (minus the thickening effect)?

A farmkid in his late 20's feels a need to close this "gap". Please help him.

All good questions.

The only theory I can think of is that current technology has not found a way to do this as yet without the oil itself gelling.

I'll take another look at the chemical synthesis of the process and see if I can get you a better answer.

 

[Extreme-Duty]

I'm glad I can keep our lube veteran occupied for so long. People are gonna love this novel calcite brew.

 

[MolaKule]

Nope just doing a lot of testing.

My first guess was correct. As the calcium carbonate becomes more crystalline it also becomes more insoluble so what you have is a more gel-like product with larger suspended crystalline particles.

While this process lends itself well to greases, it does not lend itself to liquid lubricants.

You can only push the amount of CaCO3 so far before the liquid becomes saturated and the gells predominate.

 

[MolaKule]

Editing timeout:

You can only increase the amount of CaCO3 so far before the liquid becomes saturated and the gells predominate.


You can only push chemical synthesis reactions so far.

 

[friendly_jacek]

Isn't that available as Calcinate?

http://www.chemtura.com/bu/v/index.jsp?v...p;vgnextchan...

Or in racing oils/additives (Oil Extreme)?

 

[MolaKule]

Those CaS additives are oil soluble or water soluble additives not synthesized to the point of gelling.

Many addtive package manf. use the 30 TBN or higher CaS compounds as part of their detergent packages.

Some additive package manf. may use calcium salicylates instead of calcium sulfonates.

The calcium compounds with the higher carbonate content are often used in gear lubes.

Different calcium compounds for different applications.

 

[Extreme-Duty]

Thanks Mola. Sadly, every technology has its limits.

It becomes clear that the thickener does "the job" in these greases. With that in mind, I tend to believe that the inherent AW/EP properties decline with increased base oil viscosities as well as with lowered NLGI consistencies.

The NLGI 1.5 CSC moly grease with 650 cSt.@40C base oil I am looking at really starts getting boring by now, it probably needs extra sulfur to make it to a 500 Kg 4-ball weld load.

I am still searching for the very best off road grease for highly loaded plain bearings in kingpins, ball joints and front end loaders and it seems like I am at the very beginning....again.

 

[Tempest]

Check CAT Desert Gold.