Granted Patent B2

US 12,623,943 · App. 18/253,290 · Granted May 12, 2026

Inventors: Lars Elmekilde Hansen (Hedehusene, DK); Haosheng Zhou (Hedehusene, DK)

Assignee: Rockwool A/S

C03B5/2353C03B5/12C03B37/04C03C13/06C03B2211/30

Abstract

Claims (51)

1 . A process for preparing a mineral melt in a cupola furnace, said process comprising supplying mineral material to the cupola furnace, and providing heating energy to the cupola furnace, said cupola furnace having a base, such that said mineral material is melted to form a mineral melt that collects in the base of the cupola furnace, and wherein the process produces off-gas,

wherein:

the cupola furnace comprises at least two temperature zones, including a hot zone at the base of the cupola furnace and an oxidation zone above the hot zone;

(i) the cupola furnace is equipped with at least one tuyere providing a source of oxygen in the oxidation zone;

(ii) the cupola furnace comprises at least one plasma torch that uses as carrier gas nitrogen, carbon monoxide, carbon dioxide, or a mixture thereof, and provides plasma heating in the hot zone;

(iii) greater than 50% of the heating energy provided to the cupola furnace is provided by the at least one plasma torch;

(iv) the temperature in the oxidation zone is below 1,400° C.;

(v) the temperature in the hot zone is greater than the temperature in the oxidation zone;

(vi) water is substantially excluded from any zone of the cupola furnace where the temperature is above 750° C.

2 . The process as claimed in claim 1 , wherein greater than 60% of the heating energy provided to the cupola furnace is provided by the at least one plasma torch.

3 . The process as claimed in claim 1 , wherein the temperature in the oxidation zone is below 1,300° C.

4 . The process as claimed in claim 1 , wherein heating is provided in the hot zone solely by the at least one plasma torch.

5 . The process as claimed claim 1 , wherein the temperature in the hot zone is above 800° C.

6 . The process as claimed in claim 1 , wherein the carrier gas enthalpy is from 2.0 to 6.0 kWh/Nm 3 .

7 . The process as claimed in claim 1 , wherein the melt has the following composition expressed as oxides, by weight %:

SiO 2

35-50

Al 2 O 3

12-30

TiO 2

up to 2

Fe 2 O 3

 2-12

CaO

 5-30

MgO

 0-15

Na 2 O

 0-15

K 2 O

 0-15

P 2 O 5

0-3

MnO

0-3

B 2 O 3

 0-3.

8 . The process as claimed in claim 1 , wherein the cupola furnace produces off-gas comprising NO x in an amount of less than 400 ppm.

9 . The process as claimed in claim 1 , wherein the carrier gas is nitrogen.

10 . The process as claimed in claim 1 , wherein the carrier gas comprises at least one component of the off-gas.

11 . The process as claimed in claim 10 , wherein the at least one component of the off-gas undergoes off-gas cleaning prior to its use as carrier gas.

12 . The process as claimed in claim 10 , wherein the carrier gas consists of the at least one component of the off-gas.

13 . The process as claimed in claim 1 , wherein greater than 70% the heating energy provided to the cupola furnace is provided by the at least one plasma torch.

14 . The process as claimed in claim 1 , wherein the temperature in the oxidation zone is below 1,200° C.

15 . The process as claimed claim 1 , wherein the temperature in the hot zone is above 900° C.

16 . The process as claimed in claim 1 , wherein the carrier gas enthalpy is from 3.0 to 5.0 kWh/Nm 3 .

17 . The process as claimed in claim 1 , wherein the cupola furnace produces off-gas comprising hydrogen in an amount of less than 20,000 ppm.

18 . A process for manufacturing man-made vitreous fibre (MMVF) comprising the steps of:

(i) forming a melt using a process as defined in claim 1 ;

(ii) fiberizing the melt by means of an internal or external spinning process; and

(iii) collecting the formed fibres.

Assignments (1)

Priority Claims (1)

Continuity (1)

References Cited (14)