6.2 Activities

Activity 1. Insert the most appropriate word from the text

1. …………… is the removal from a given lot of material a portion that is representative of the whole yet of convenient size for analysis.

2. …………..… sampling is usually expensive, slow, and inaccurate.

3. In …………………… an electric discharge is established between a pair of electrodes, one of which is made of the material being analyzed.

4. A successful separation of a valuable mineral from its ore can be determined by …………………….… testing.

5. The amount of emitted ………….…is related to the concentration of individual elements in the sample.

6. Particles of less ………………….. than the liquid remain afloat, while denser particles sink.

7. Several different fractions of particles with the ………..… density can be produced.

8. The sensitivity and precision of this method are poor for elements of low atomic ……………………..

9. Many different sampling ………………………… are available, including shovels, pipe samplers, and automatic machine samplers.

10. Detection and measurement of the wavelengths and intensities of the emission spectra reveal the identities and concentrations of the ……………….… in the sample.

Activity 2. Complete the expressions given below

1. single-sized	size
2. international	particles
3 . valuable	methods
4. mesh	testing
5. mineral	concentrations
6. atomic	fraction
7. heavy-liquid	analysis
8. chemical	number
9. low	mineral
10. measurement	standards

Activity 3. Match words with the definitions

1Sampling	A-a sample bombarded with X rays gives off fluorescent X-radiation of wavelengths characteristic of its elements
2 Emission spectroscopy	B-a successful separation of a valuable mineral from its ore determined by heavy-liquid testing
3 X-ray fluorescence spectroscopy	C- the removal from a given lot of material a portion that is representative of the whole yet of convenient size for analysis
4 Detection	D- an electric discharge is established between a pair of electrodes, one of which is made of the material being analyzed
5 Mineralogical analysis	E-Sensing

Activity 4. Complete the table

Types of analysis	Description	Analyzed elements
Chemical analysis
Mineralogical analysis
Size analysis

Activity 5. Define whether the statements are true or false

1. As a rule, comminution begins by crushing the ore to below a certain size and finishes by grinding it into powder.

2. Most ores, however, are made up of hard, tough rock masses that must be crushed before the valuable minerals can be released

3. Autogenous mills operate with grinding bodies; instead, the coarser part of the ore simply grinds itself and the smaller fractions.

4. The cylinders are pressed together under low pressure, so that comminution takes place in the material bed between them

5. In order to produce a crushed material suitable for use as mill feed grinding is done in stages.

6. Roll crusher consists essentially of two cylinders that are mounted on horizontal shafts and driven in opposite directions

7. In large-scale operations this is accomplished by taking advantage of the different properties of the minerals to be separated.

8. In this stage, the ore is crushed in cone crushers to less than 20 to 25 millimetres.

9. Concentration involves the separation of valuable minerals from the other raw materials received from the crushing mill.

10. Yet another development, combining the processes of crushing and grinding, is the roll crusher.

Activity 6. Briefly describe the following processes

Sampling, Analysis, Comminution, Crushing, Grinding, Crushing / Grinding, Concentration

Activity 7. Discuss the following

1. What can you tell about autogenous and semiautogenous mills?

2. What is the advantage of roll crusher?

3. What is the purpose of crushing?

4. What mixtures require little or no crushing?

5. What is grinding body?

Activity 8. List the advantages and disadvantages of various methods of analysis

	Advantages	Disadvantages
Chemical analysis
Emission spectroscopy
X-ray fluorescence spectroscopy
Heavy-liquid testing
Size analysis
Optical measurement