Chemical purity
|
||||||
Chemical purity is determined by the content of the main substance, expressed as a percentage and is defined as the difference between 100% and the sum of selected controlled chemical impurities.
Controlled (or managed) impurities - a list of chemical elements, selected from various considerations and tasks, measured in a sample and used to determine chemical purity. |
In fact, "chemical purity" - "Appointed NUMBER", is obtained by subtracting from 100% the amount in% of the content of chemical elements from some selected list. If it is not obvious which list of impurities is in question, then it is worth specifying according to which list.
Obviously, to determine the chemical purity, it is necessary to know the quantitative values of these impurities. Chemical composition of impurities - a list of controlled impurities with the quantitative value of some of them, certain groups or each of the impurities. By choosing different lists of elements, you can get very different such numbers. |
|||||
In some way it is necessary to measure, obtain quantitative values of the content of impurities from the selected list. Some "tool and rules to use it" are needed.
The concept of "Method of analysis" appears. |
||||||
Analysis Methods
|
||||||
The method of analysis is a method of obtaining information about the chemical composition of a substance based on the use of selected chemical and physical processes and laws
The method of analysis is a sequence of preparatory activities, measurement and interpretation of the results using appropriate consumables, tools and equipment. The method of analysis must correspond to the level of chemical purity of the tested sample and the list of measured impurities. Different methods measure the same impurities with different limits, some methods cannot, in principle, determine some impurities correctly or completely, in view of the chemical and physical processes and laws inherent in them. To test very pure samples against a list of elements, a combination of analysis methods is often needed. |
Basically, the methods are characterized by the following quantitative and qualitative parameters:
|
|||||
We have a certain list of elements, we have determined chemical purity by some method. What do we want? Obviously, we want to have certain characteristics and properties, we do not have the ability to determine them completely or promptly. On the basis of something, it is necessary to draw conclusions, to correlate with something.
There is a concept "Standards and TS (technical specifications)". |
||||||
Standards and specifications
|
||||||
Standard or TS in the broad sense of the word - a sample, standard, norms, characteristics, etc., taken as initial ones for comparing other similar objects with them according to certain rules.
The features of copper are determined not so much by the copper content (chemical purity), but by the content of specific impurities and their specific amount, that is, by a specific chemical composition. Different chemical elements affect different characteristics of both the product and the technological processes themselves in different ways. |
Standards and TS (technical specifications) define the following main reference parameters:
Several options "composition of impurities + min chemical purity" - different Grades and / or Categories according to this Standard or Specification.
|
|||||
Controlled impurities according to GOST 859, ASTM B170 and some specifications :
|
||||||||||||||||||||||||||||||||
Total different
|
1
|
2
|
3
|
4
|
5
|
6
|
7
|
8
|
9
|
10
|
11
|
12
|
13
|
14
|
15
|
16
|
17
|
18
|
19
|
20
|
21
|
22
|
23
|
24
|
25
|
26
|
||||||
chemical elements
|
26
|
O
|
S
|
P
|
Ni
|
Zn
|
As
|
Se
|
Sn
|
Sb
|
Te
|
Pb
|
Bi
|
Fe
|
Ag
|
Mn
|
Cd
|
Si
|
Cr
|
Co
|
Al
|
Mg
|
Ti
|
Mo
|
Ca
|
K
|
W
|
|||||
Standards
|
Cu
|
|||||||||||||||||||||||||||||||
1
|
ГОСТ 859-2001
cathode copper |
2N-4N
|
19
|
O
|
S
|
P
|
Ni
|
Zn
|
As
|
Se
|
Sn
|
Sb
|
Te
|
Pb
|
Bi
|
Fe
|
Ag
|
Mn
|
Cd
|
Si
|
Cr
|
Co
|
||||||||||
2
|
ГОСТ 859-2001
cast copper |
2N-4N
|
12+2
|
*
|
O
|
S
|
P
|
Ni
|
Zn
|
As
|
Se
|
Sn
|
Sb
|
Te
|
Pb
|
Bi
|
Fe
|
Ag
|
||||||||||||||
3
|
ASTM B170
cast copper |
2N-4N
|
16
|
O
|
S
|
P
|
Ni
|
Zn
|
As
|
Se
|
Sn
|
Sb
|
Te
|
Pb
|
Bi
|
Fe
|
Ag
|
Mn
|
Cd
|
|||||||||||||
TS
|
Cu
|
|||||||||||||||||||||||||||||||
4
|
Sibneotech
cast copper |
5N5-7N
|
16
|
O
|
S
|
P
|
Ni
|
Zn
|
As
|
Se
|
Sn
|
Sb
|
Te
|
Pb
|
Bi
|
Fe
|
Ag
|
Mn
|
Cd
|
|||||||||||||
5
|
Umicore Ltd
cast copper |
4N5-6N
|
12+2
|
*
|
O
|
S
|
P
|
Ni
|
Zn
|
As
|
-
|
Sn
|
Sb
|
-
|
Pb
|
Bi
|
Fe
|
Ag
|
Mn
|
Cd
|
||||||||||||
6
|
Acrotec Ltd
cast copper |
6N-9N
|
10
|
-
|
S
|
-
|
Ni
|
-
|
As
|
Se
|
-
|
Sb
|
-
|
Pb
|
-
|
Fe
|
Ag
|
-
|
-
|
Si
|
Al
|
|||||||||||
7
|
Sigma-Aldriich Corp
Bars |
5N
|
15
|
-
|
-
|
-
|
Ni
|
Zn
|
As
|
-
|
Sn
|
Sb
|
-
|
-
|
Bi
|
Fe
|
Ag
|
-
|
Cd
|
Cr
|
Al
|
Ti
|
Ca
|
K
|
W
|
|||||||
8
|
Sigma-Aldriich Corp
Powder |
5N
|
13
|
-
|
-
|
-
|
Ni
|
Zn
|
As
|
-
|
Sn
|
Sb
|
-
|
-
|
Bi
|
Fe
|
Ag
|
-
|
Cd
|
Cr
|
Al
|
Ti
|
Ca
|
K
|
W
|
|||||||
9
|
TS №1
Powder |
4N?
|
9
|
-
|
-
|
-
|
Ni
|
Zn
|
-
|
-
|
-
|
Sb
|
-
|
-
|
-
|
Fe
|
-
|
Mn
|
Cd
|
Al
|
Ti
|
Mo
|
||||||||||
10
|
TS №2
Powder? |
4N?
|
6
|
-
|
-
|
P
|
-
|
-
|
-
|
-
|
-
|
-
|
-
|
-
|
-
|
-
|
-
|
-
|
Cd
|
Al
|
Mg
|
Ti
|
Mo
|
|||||||||
*
|
Se, Te in GOST 859 cast and O, S in Umocore are not calculated, but are indicated and limited
|
|||||||||||||||||||||||||||||||
Chemical purity of 3 samples of copper grade M1 and 2 of our median samples of grades Standard and Extra, depending on the lists of impurities and on the methods of analysis:
|
||||||||||||||||
Standards
|
TS (specifications)
|
|||||||||||||||
1
|
2
|
3
|
4
|
5
|
6
|
7
|
8
|
9
|
10
|
|||||||
№
|
Copper sample
|
Method
|
All (26)
|
ГОСТ 859
cathode |
ГОСТ 859
cast |
ASTM B170
cast |
Сибнеотэк
cast |
Umicore
cast |
Acrotec
cast |
Sigma
cast |
Sigma
powder |
ТУ №1
powder |
ТУ №2
powder |
|||
2N-4N
|
2N-4N
|
2N-4N
|
5N5-7N
|
2N5-6N
|
6N-9N
|
5N
|
5N
|
4N-5N?
|
4N-5N?
|
|||||||
М1 GOST 859
|
||||||||||||||||
1
|
М1
|
LMS
|
3 N 2
|
3 N 2
|
3 N 2
|
3 N 2
|
3 N 2
|
3 N 4
|
4 N
|
3 N 5
|
4 N
|
4 N
|
4 N 8
|
|||
2
|
M1
|
LMS
|
3 N 3
|
3 N 3
|
3 N 3
|
3 N 3
|
3 N 3
|
3 N 6
|
4 N
|
3 N 6
|
4 N
|
4 N
|
4 N 6
|
|||
3
|
M1
|
LMS
|
3 N 5
|
3 N 5
|
3 N 5
|
3 N 5
|
3 N 5
|
4 N 8
|
5 N
|
5 N
|
5 N
|
5 N
|
5 N 4
|
|||
Sibneotech
|
||||||||||||||||
4
|
Standard - med
|
LMS
|
5 N
|
5 N 1
|
5 N 2
|
5 N 2
|
5 N 2
|
5 N 7
|
5 N 5
|
5 N 7
|
5 N 7
|
5 N 8
|
6 N
|
|||
5
|
Extra - med
|
LMS
|
5 N 1
|
5 N 1
|
5 N 2
|
5 N 2
|
5 N 2
|
5 N 8
|
5 N 5
|
5 N 8
|
5 N 8
|
5 N 8
|
6 N
|
|||
4
|
Standard - med
|
LMS+GDMS
|
5 N 6
|
5 N 7
|
5 N 7
|
5 N 7
|
5 N 7
|
6 N
|
6 N
|
6 N
|
6 N
|
6 N 6
|
7 N +
|
|||
5
|
Extra - med
|
LMS+GDMS
|
5 N 7
|
5 N 7
|
5 N 8
|
5 N 8
|
5 N 8
|
6 N 7
|
6 N 3
|
6 N 7
|
6 N 7
|
7 N
|
7 N +
|
|||
Example of different chemical purity for 2 different samples with the same method of analysis and different controlled impurities :
|
|||||||||||
1
|
2
|
3 (Characteristics)
|
|||||||||
Sample
|
Method
|
Chemical purity
|
List of impurities
|
% IACS
|
RRR 4.2K=R 293K /R 4.2K
|
λ 4.2K / λ 293K
|
|||||
М1 №3
|
LMS
|
5N4
|
ТУ №2
|
<100
|
50-100
|
1
|
|||||
Standard - med
|
LMS
|
5N1
|
ГОСТ 859
|
104-105
|
2000
|
25-30
|