Development of a wear index and its methodology related to mineral processing - Part I

Abstract

This Master Thesis was performed for Sandvik SRP in collaboration with the Institution for Industrial Production Faculty of Engineering at Lund University.
Tool wear is one of the main cost drivers in the mining industry. By being able to characterize what kind of rock involved, you can choose a more beneficial tool material to minimize the wear and thereby reduce the maintenance costs.
The purpose of this thesis is to see if there is a correlation between the surface and the wear. The work had to be divided into Part I and Part II due to the size of the project. In Part I nanoindentation was used to get data to models that describes the variation in hardness, different hardness phases and the quantity of each phase for the rock being examined. Nanoindentation examines the rock at nano-scale by forcing a diamond Berkovich indenter into the rock hundreds of times. A part of this thesis was also to find a standard methodology to prepare the samples for the nanoindentation, which requires a good surface roughness.
The work started with a theory study to know the basics about the method and a literature study to see what have been done before.
During the work new experiences were given by using a trial and error method when preparing the samples. The methodology has been described carefully to be able to repeat the process regardless of the rock being examined. However, the grinding and polishing processes can be different depending on the rock, meaning that the time for each process can vary.
The results from the nanoindentation have been put into a table with expected wear based on internal order of the rocks involved. The table is supposed to be a basis used to find a correlation between the surface hardness and the wear after performing Part II. In the end of this thesis different suggestion of how to perform Part II are given.

Popular Abstract

Nanoindentation as a methodology to predict the wear?

Abrasive wear on the tools is a crucial factor for the maintenance costs and the spare parts consumption in the mining industry. By using the optimal tool material a reduced wear tendency can reduce the costs. This thesis has used nanoindentation as an attempt to predict the wear by studying the surface hardness.

Minerals and gemstones like iron ore, gold and diamonds are crucial for the survival of mankind. They are used in almost all applications either as a part in the product itself or to produce the goods. Due to the fact that earth contains a limited amount of the minerals, the mining industry is an industry with a future vision.

Nanoindentation is an advanced method that requires expensive equipment. It is a fairly new method that usually is used to study metal properties and not used in the mining industry. Therefore this is an unexplored area where big advantages for the company can be made if the method works properly. The time for conduction tests are also at a relatively small scale compared to other advanced techniques and nanoindentation does not require a lot of supervision.

This thesis has examined several different rocks by using nanoindentation to study the surface hardness. However, it is not just as simple as collect a rock and put it into the machine. There are a lot of preparation steps before the samples ends up in the indenter. In the thesis a preparation process of the rocks has been developed. The preparation process contains several steps to achieve a good surface roughness, but still it has been developed as a time efficient process. Different approaches were made due to the indent pattern to see if they affected the results.

The results have carefully been analyzed to see if it the different rocks indicate to have different wear patterns and probability plots by using Weibull distributions. A deeper analyze was also made and the hardness range was divided into four subgroups. The final results showed differences in the surface hardness between some of the rocks and an expected wear table in particular order of the examined rocks was established.

An important factor of this project is that friction tests have to be made to confirm nanoindentation as an appropriate methodology to predict the tool wear and in the end the costs. If it gets confirmed rocks from all over the world, where minerals are found, can be collected. Samples can then be taken out to conduct the indentation tests. The advantage for the company can be of great use to predict the exact cost and present it for the customer.





2016-06-13
André Larsson

CODEN:LUTMDN/(TMMV-5276)/1-52/2016

• author: Larsson, André
• supervisor: Jinming Zhou; Johan Persson; Hamid Manouchehri; Per Hedvall
• organization: Production and Materials Engineering
• course: MMTM01 20161
• year: 2016
• type: H2 - Master's Degree (Two Years)
• subject: Technology and Engineering
• keywords: Nanoindentation, Berkovich indenter, wear, surface hardness, rock, minerals, manganese steel, mining, comminution.
• report number: CODEN:LUTMDN/(TMMV-5276)/1-52/2016
• language: English
• id: 8882612
• date added to LUP: 2016-06-21 13:24:51
• date last changed: 2016-06-21 13:24:51