Mineral wool

Abstract

Mineral wool fibers having a mineral wool fiber composition are manufactured by introducing batch materials into a melter, melting the mineral batch materials in the melter to provide a melt and fiberizing the melt to form the mineral wool fibers. The batch materials comprise i) fibers having a first batch material composition which is different from the mineral wool fiber composition and consisting of scrap fibers which have broken at a bushing producing continuous fibers; and ii) one of more additional mineral batch materials.

Claims

1. A method of manufacturing mineral wool fibers having a mineral wool fiber composition, wherein the mineral wool fiber composition comprises: 30 to 55 wt % SiO.sub.2, and 10 to 30 wt % Al.sub.2O.sub.3, and 4 to 14 wt % total iron expressed as Fe.sub.2O.sub.3, and a combination selected from: a) 20 to 35 wt % of the combination of CaO and MgO; and less than 8 wt % of the combination of Na.sub.2O and K.sub.2O; and b) 8 to 23 wt % of the combination of CaO and MgO; and 4 to 24 wt % of the combination of Na.sub.2O and K.sub.2O; the method comprising: providing a first batch material in the form of fibers having a first batch material composition, the fibers of the first batch material consisting of scrap fibers which have broken at a bushing producing continuous fibers, the first batch material composition being different from the mineral wool fiber composition, and the first batch material composition comprising: 52 to 62 wt % SiO.sub.2, and 12 to 16 wt % Al.sub.2O.sub.3, and 16 to 25 wt % CaO, and 0 to 5 wt % MgO, and 0 to 10 wt % B.sub.2O.sub.3, and 0 to 2 wt % of the combination of Li.sub.2O+Na.sub.2O+K.sub.2O, and 0 to 1.5 wt % TiO.sub.2, and 0.005 to 1 wt % total iron expressed as Fe.sub.2O.sub.3, and 0 to 1 wt % fluoride; providing one of more additional mineral batch materials; introducing the mineral batch materials into a melter, melting the mineral batch materials in the melter to provide a melt and fiberizing the melt to form the mineral wool fibers that have the mineral wool fiber composition.

2. The method of claim 1, wherein the fibers of the first batch material comprise an organic coating present in a quantity of at least 2 wt % with respect to the total weight of the first batch material.

3. The method of claim 1, wherein the first batch material constitutes at least 10 to 60 wt % of the mineral batch materials.

4. The method of claim 1, wherein the introducing the mineral batch materials into a melter comprises introducing the mineral batch materials into a melter selected from a submerged combustion melter, an electric arc furnace and a circulating furnace.

5. The method of claim 1 wherein the moisture content of the first batch material when introduced in to the melter is at least 10 wt %.

6. The method of claim 1, wherein the one of more additional mineral batch materials comprise at least one material selected from: dolomite, calcined bauxite, steel slag and combinations thereof.

7. The method of claim 1, wherein the one of more additional mineral batch materials comprise recycled portions of mineral wool insulation product from previous production of the mineral wool fibers.

8. The method of claim 1, wherein the introducing the mineral batch materials into a melter comprises introducing the mineral batch into a cupola furnace.

9. The method of claim 1, wherein first batch material composition comprises. 53 to 56 wt % SiO.sub.2, and 12 to 16 wt % Al.sub.2O.sub.3, and 20 to 24 wt % CaO, and 0 to 2 wt % MgO, and 4 to 8 wt % B.sub.2O.sub.3 and 0.5 to 1.8 wt % of the combination of Li.sub.2O+Na.sub.2O+K.sub.2O, and 0 to 0.5 wt % TiO.sub.2, and 0.005 to 0.75 wt % total iron expressed as Fe.sub.2O.sub.3.

10. The method of claim 1, wherein first batch material composition comprises. 55 to 57 wt % SiO.sub.2, and 12 to 15 wt % Al.sub.2O.sub.3, and 23 to 26 wt % CaO, and 1 to 4.5 wt % MgO, and 0.01 to 2.5 wt % B.sub.2O.sub.3 and 0.5 to 1.8 wt % of the combination of Li.sub.2O+Na.sub.2O +K2O, and 0.01 to 1.5 wt % TiO.sub.2, and 0.005 to 0.75 wt % total iron expressed as Fe.sub.2O.sub.3.

11. A method of manufacturing mineral wool fibers having a mineral wool fiber composition, the method comprising: providing a first batch material in the form of fibers having a first batch material composition, the fibers of the first batch material consisting of scrap fibers which have broken at a bushing producing continuous fibers, the first batch material composition being different from the mineral wool fiber composition, and the first batch material composition comprising: 52 to 62 wt % SiO.sub.2, and 12 to 16 wt % Al.sub.2O.sub.3, and 16 to 25 wt % CaO, and 0 to 5 wt % MgO, and 0 to 10 wt % B.sub.2O.sub.3, and 0 to 2 wt % of the combination of Li.sub.2O+Na.sub.2O+K.sub.2O, and 0 to 1.5 wt % TiO.sub.2, and 0.005 to 1 wt % total iron expressed as Fe.sub.2O.sub.3, and 0 to 1 wt % fluoride; providing one of more additional mineral batch materials; introducing the mineral batch materials into a submerged combustion melter, wherein the first batch material constitutes at least 10 wt % of the mineral batch materials, wherein the moisture content of the first batch material when introduced into the submerged combustion melter is at least 10 wt %, wherein the first batch material is introduced into the submerged combustion melter in the form of loose fibers, and wherein the one of more additional mineral batch materials comprise at least one material selected from: dolomite, calcined bauxite, steel slag, recycled portions of the mineral wool insulation product from previous production of the mineral wool fibers and combinations thereof; melting the mineral batch materials in the submerged combustion melter to provide a melt and fiberizing the melt to form the mineral wool fibers have the mineral wool fiber composition; wherein the mineral wool fiber composition comprises 30 to 55 wt % SiO.sub.2, and 10 to 30 wt % Al.sub.2O.sub.3, and 4 to 14 wt % total iron expressed as Fe.sub.2O.sub.3, and a combination selected from: a) 20 to 35 wt % of the combination of CaO and MgO; and less than 8 wt % of the combination of Na.sub.2O and K.sub.2O; and b) 8 to 23 wt % of the combination of CaO and MgO; and 4 to 24 wt % of the combination of Na.sub.2O and K.sub.2O.

Description

EXAMPLE 1

(1) The following mineral batch materials were melted in a laboratory melter:

(2) 27 wt % of a first batch material in the form of fibers;

(3) 50 wt % of a second batch material in the form of fibers;

(4) 10 wt % crushed dolomite (batch material 3);

(5) 9 wt % crushed steel slag (batch material 4);

(6) 4 wt % crushed calcined bauxite (batch material 5);

(7) where

(8) a) the wt % above is expressed in relation to the total weight of the combination of all of the mineral batch materials;

(9) b) the first batch material consisted of about: 60.1 wt % SiO.sub.2, 13.2 wt % Al.sub.2O.sub.3, 22.1 wt % CaO, 3.1 wt % MgO, less than 0.1 wt % B.sub.2O.sub.3, less than 0.1 wt % Li.sub.2O, 0.9 wt % Na.sub.2O, less than 0.1 wt % K.sub.2O, 0.5 wt % TiO.sub.2, and less than 0.1 wt % total iron expressed as Fe.sub.2O.sub.3;
c) the second batch material consisted of about: 40.2 wt %; SiO.sub.2, 17.3 wt % Al.sub.2O.sub.3, 18.5 wt % CaO, 10.6 wt % MgO, 7.8 wt % total iron expressed as Fe.sub.2O.sub.3, 2.1 wt % Na.sub.2O, 0.8 wt % K.sub.2O, 1.5 wt % TiO.sub.2 and 0.2 wt % P.sub.2O.sub.3.

(10) The batch materials were sequentially: dried at 105° C.; crushed in a vibratory mill; mixed in a rotary mixer; and melted in an electric furnace at 1450° C. for 4 hours in alumina crucibles.

(11) The composition of the melt produced comprised about: 41.3 wt % SiO.sub.2, 18.8 wt % Al.sub.2O.sub.3, 21.5 wt % CaO, 9.1 wt % MgO, 6.2 wt % total iron expressed as Fe.sub.2O.sub.3, 1.5 wt % Na.sub.2O, 0.5 wt % K.sub.2O, 1.2 wt % TiO.sub.2 and 0.1 wt % P.sub.2O.sub.3. It had a log 3 viscosity permitting fiberization on a cascade spinner and a bio-solubility satisfying the requirements of Note Q.

(12) The first batch material had a composition significantly different from the composition of the melt produced. For example, the first batch material had:

(13) a quantity of SiO.sub.2 which was greater than that of the melt produced by 18.8 percentage points (ie 60.1 wt % minus 41.3 wt %);

(14) a quantity of Al.sub.2O.sub.3 which was less than that of the melt produced by 5.6 percentage points (ie 18.8 wt % minus 13.2 wt %);

(15) a quantity of CaO which was greater than that of the melt produced by 0.6 percentage points (ie 22.1 wt % minus 21.5 wt %);

(16) a quantity of MgO which was less than that of the melt produced by 6 percentage points (ie 9.1 wt % minus 3.1 wt %); and

(17) a quantity of total iron expressed as Fe.sub.2O.sub.3 which was less than that of the melt produced by 6.1 percentage points (ie 6.2 wt % minus 0.1 wt %).

EXAMPLE 2

(18) A melt having the following composition: 52.0 wt % SiO.sub.2, 15.1 wt % Al.sub.2O.sub.3, 13.0 wt % CaO, 6.0 wt % MgO, 1.6 wt % TiO.sub.2, 7.4 wt % total iron expressed as Fe.sub.2O.sub.3, 2.6 wt % Na.sub.2O, 1.5 wt % K.sub.2O, 0.4 wt % F, 0.1 wt % Mn.sub.2O.sub.3 and 0.4 wt % P.sub.2O.sub.5, and which is suitable for fiberizing may be obtained by melting the following quantity of batch materials, notably in a submerged combustion melter:

(19) 40 wt % of scrap fibers (batch material 1);

(20) 2 wt % steel slag (batch material 2);

(21) 58 wt % basalt (batch material 3);

(22) wherein Table 1 below give the composition of the batch materials in wt %. The quantities in Table 1 are expressed when fully calcined; the loss represents primarily decarboxylation of calcinates and loss of water of crystallization

(23) TABLE-US-00001 TABLE 1 composition of batch materials in wt % SiO.sub.2 Al.sub.2O.sub.3 CaO MgO TiO.sub.2 Fe.sub.2O.sub.3 Na.sub.2O K.sub.2O F Mn.sub.2O.sub.3 P.sub.2O.sub.5 Loss Batch material 1 59.5 15.0 18.0 3.0 1.0 0.5 1.5 0.5 1.0 Scrap fibers Batch material 2 11.3 5.3 22.8 5.6 47.2 6.7 0.6 0.5 Steel slag Batch material 3 48.1 15.4 9.2 8 2.1 10.7 3.4 2.2 0.7 0.2 Basalt

(24) As it can be seen, the first batch material has a composition significantly different from the composition of the melt or mineral fibers produced.