Laboratory Testing & General Mineral Processing Engineering

Laboratory Testing & General Mineral Processing Engineering

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Bond Crushing Work Index (3 replies)

C
crsp
6 years ago
crsp 6 years ago

Dear all,

while researching about the bond crushing work index (Wic), I realised, that the procedure of the test is described differently in different sources. The same seems to be true for sampling. Two examples:

Bergstrom 1985 _ Crushability and Grindability: The hights of the hammers start for every specimen at the start hight of 10°

vs.

Bond 1946 _ Crushing tests by impact and pressure: For breaking a succeeding specimen, the hammers are released from a height slightly under that of the preceeding specimen

Bond and Bergstrom did not mentioned a specific sample geometry (just that the sample shouldn´t be slabby or acicular). Sandvik and Metso on the contrary seems to demand a cubical shape of the samples (more "citeable" sources needed).

 

Sometimes it appears to me, that there are, in some papers, confusions about the units (ton/tonne, constants not adapted to units, imperial/metric) and the calculations (units don´t add up correctly).

In another case, the specs of the Bond apparatus are discribed in that way, that the resulting WiC is 4 times the WiC which would be measured at the same angle with the apparatus described by Bond and Bergstrom. --> For calculating the energy, the hight of the center of mass should be used, or??!

My Question is, what are the scientific papers/books nowaday used as basis for calculating and performing the Bond WiC test? Is there a kind of standard?

I'm looking forward to hearing your opinions on that subject,

best regards,

Caspar

 

b
Robert
6 years ago
Robert 6 years ago
Like

The Global Mining Standards and Guidelines Committee has developed a guideline for standardizing the Bond group of methods. This can be found at:

http://www.globalminingstandards.org/working_group_categories/industrial-comminution-efficiency-ice/standardizing-the-bond-method/

 

This was probably the most difficult of the Bond Methods to address.

 

C
crsp
6 years ago
crsp 6 years ago
Like

Dear Robert,

thank you very much for your reply and the link. That`s very helpful.

But I have to say, that I would have expected for a standard a more strict description of the procedure and the apparatus.

To specify the length and weight of the hammers, but not specifying the centre of mass?? What about the weight of the hammer shaft, is it neglectible; what if it´s not?

To leave it up to the person conducting the test to choose the starting angle, the subsequent anlges etc... ?? I`m as confused as I was before.

Can you recommend more helpfull literature? Especially those in SME or AIME transactions are difficult to find as digital copies.

Best regards,

Caspar

b
Robert
6 years ago
Robert 6 years ago
Like

You raise a great point. The Bond crushing test is the most poorly described of the methods. It is interested to hear the approach of different laboratories that still perform this test.

I'm willing to provide some copies of relevant Bond crushing test papers. Attached.

What references do you have to avoid replication. Do you have the Bergstrom summary from 1985?

flavel-1981-Particle-Breakage-Studies-In-An-Impact-Crushing-Environment.pdfBond-F-1946-Crushing-tests-by-pressure-impact.pdf

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