Cupellation is the second and most important step in the fire assay process. Therefore, the quality of the cupel is crucial. Qingdao Decent Group aims to manufacture a full range of fire-assay cupels with premium quality and competitive cost.
Our magnesia cupel uses high-quality raw materials and a unique formula. And its composition includes up to 96% magnesium oxide and special flux. Our magnesia cupel absorbs more lead oxide than ordinary bone ash cupels. So our magnesia cupel has strong mechanical strength and perfect quality uniformity.
In the process of cupellation, the magnesia cupel will not cause splashing of lead, and can quickly absorb a large amount of lead oxide. And the magnesia cupels will not crack and pit. After the cupellation process, the gold-silver particles in the cupel can be easily removed.
Our magnesia cupels can be stored for a long time without compromising quality. It does not require pre-drying for the first use and always maintains a low loss of gold, silver and precious metals. What's more, our fire assay cupels are regularly sample tested in our own laboratory to ensure that we always provide our customers with quality cupels.
[ Key Advantages ]
• High quality, perfect uniform appearance, smooth surface
• High mechanical strength • High thermal shock resistance
• Rapid absorption of lead oxide, low loss of gold and silver
• No lead spatter, no cracks, no pitting
• Easy to remove beads
• Customized according to customer needs
[ The Process of Cupellation ]
Cupellation is the second step of the fire assay process. During cupellation, put the lead button which formed in fusion into the cupel, and melt it at 900 degrees Celsius in the cupellation furnace. The molten lead contacts with the oxygen in the air to become lead oxide. Due to the effect of surface tension, most of the lead oxide is absorbed by the porous cupels, and a small part of the lead oxide is volatilized. Gold and silver are not oxidized, but become alloy particles and remain at the bottom of the cupel, awaiting the next gold separation treatment.
[ Technical Parameters ]
Model No.
Top OD
(mm)-D
Top ID
(mm)-D1
Base OD
(mm)-D2
Height
(mm)-H
Depth
(mm)-H1
Height of Ridge
(mm)-H2
Weight
(g)
Pcs/Carton
Carton Dimension
(cm)
2X
24
18
19
17
8
4.5
13
1040
34x22x22
3
26
23
20
20
5.5
8
17
864
34x22x22
4
29
24
23
22
6
8
20
486
30x30x15
4A
27
24
20
22
6
7.5
17
864
30x30x15
5
35
27
26
26
8
6.5
35
378
34x22x22
6A
40
31.2
30
26/29
11.8
6/9
62/65
200
34x22x22
7A
40
31.2
30
32
11.8
12
72
200
34x22x22
7AS
40
31.2/32
30
35/32
11.8/15
15/12
70.45/62
200
34x22x22
8A
45
38
37
35
13
13
98.3
200
38x24x21
8AM
45
33
37
35
12
15
103.4
200
38x24x21
8
44.3
34.2
34.6
27.1
8.5
9
106
200
38x24x21
8S
44
38
34
40
14
13
112
200
38x24x21
9
51
40
43
30
11
5
120
120
34x22x22
9A
51
40
39
34
15
14
123
120
34x22x22
10
60
52.6
49.7
30.2
11.5
11
150
100
34x22x22
11
56.8
47.8
48.8
44
14.8
10
166
100
34x22x22
14
110
80
88
70
24
14
320
50
34x22x22
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