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 making mineral wool fibers comprising: 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 either 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; or 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: introducing mineral batch materials in to a melter, melting the mineral batch materials to provide a melt and fiberizing the melt to form the mineral wool fibers, wherein the mineral batch materials introduced in to the melter comprise a first batch material comprising: 52 to 68 wt % SiO.sub.2, notably 52 to 62 wt % SiO.sub.2, and 12 to 30 wt % Al.sub.2O.sub.3, notably 12 to 16 wt % Al.sub.2O.sub.3, and 0 to 25 wt % CaO, notably 16 to 25 wt % CaO, and 0 to 12 wt % MgO, notably 0 to 5 wt % MgO, and 0 to 10 wt % B.sub.2O.sub.3, notably 0 to 2 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 0.05 to 1 wt % total iron expressed as Fe.sub.2O.sub.3, and 0 to 1 wt % fluoride.

2. A method in accordance with claim 1 wherein the first batch material comprises: 52 to 62 wt % SiO.sub.2, notably 52 to 56 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, notably 0 to 2 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 0.05 to 1 wt % total iron expressed as Fe.sub.2O.sub.3, and 0 to 1 wt % fluoride.

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

4. A method in accordance with claim 1 wherein the first batch material comprises less than 0.01 wt % B.sub.2O.sub.3.

5. A method in accordance with claim 1 wherein the first batch material constitutes between 10 to 60 wt % of the mineral batch materials.

6. A method in accordance with claim 1 wherein the melter is selected from a submerged combustion melter, a cupola furnace, an electric arc furnace and a circulating furnace.

7. A method in accordance with claim 1 wherein the first batch material comprises loose fibers.

8. A method in accordance with claim 7 wherein the moisture content of the first batch material when introduced in to the melter is at least 10 wt %.

9. A method in accordance with claim 1, wherein the first batch material comprises briquettes comprising fibers of the first batch material.

10. A method in accordance with claim 1, wherein the first batch material comprises fibers derived from the manufacture of continuous fibers.

11. A method in accordance with claim 1, wherein the mineral batch materials comprises a second batch material comprising fibers comprising: 30 to 55 wt %; SiO.sub.2, and 10 to 30 wt % Al.sub.2O.sub.3, and 20 to 35 wt % of the combination of CaO and MgO, and 4 to 10 wt % total iron expressed as Fe.sub.2O.sub.3, and less than 8 wt % of the combination of Na.sub.2O and K.sub.2O, and an alkali/alkaline-earth ratio which is <1.

12. A method in accordance with claim 1 wherein the mineral batch materials comprise further batch materials selected from: dolomite, calcined bauxite, steel slag and combinations thereof.

13. A method of making a mineral wool insulation product comprising: making mineral wool fibers in accordance with claim 1; spraying an aqueous binder solution to coat the mineral wool fibers whilst the mineral wool fibers are being carried in an air stream; collecting the binder coated mineral wool fibers to form a blanket of mineral fibers; and curing the aqueous binder solution by passing the blanket of mineral wool fibers through a curing oven.

14. A method in accordance with claim 13, in which the batch materials comprise recycled portions of the mineral wool insulation product, notably selected from edge trim and scrap.

15. Use of a first batch material comprising: 52 to 68 wt % SiO.sub.2, notably 52 to 62 wt % SiO.sub.2, and 12 to 30 wt % Al.sub.2O.sub.3, notably 12 to 16 wt % Al.sub.2O.sub.3, and 0 to 25 wt % CaO, notably 16 to 25 wt % CaO, and 0 to 12 wt % MgO, notably 0 to 5 wt % MgO, and 0 to 10 wt % B.sub.2O.sub.3, notably 0 to 2 wt % B.sub.2O.sub.3, and 0 to 2 wt % of the combination of Li.sub.2O +Na2O +K.sub.2O, and 0 to 1.5 wt % TiO.sub.2, and 0.05 to 1 wt % total iron expressed as Fe.sub.2O.sub.3, and 0 to 1 wt % fluoride to produce mineral wool fibers comprising 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 either 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; or 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

[0180] The following mineral batch materials were melted in a laboratory melter: [0181] 27 wt % of a first batch material in the form of fibers; [0182] 50 wt % of a second batch material in the form of fibers;

[0183] 10 wt % crushed dolomite (batch material 3); [0184] 9 wt % crushed steel slag (batch material 4); [0185] 4 wt % crushed calcined bauxite (batch material 5); [0186] where [0187] a) the wt % above is expressed in relation to the total weight of the combination of all of the mineral batch materials; [0188] 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; [0189] 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.

[0190] 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.

[0191] 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.

[0192] The first batch material had a composition significantly different from the composition of the melt produced. For example, the first batch material had:

[0193] 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 %;);

[0194] 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 %);

[0195] 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 %);

[0196] 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

[0197] 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

[0198] 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, [0199] and which is suitable for fiberizing may be obtained by melting the following quantity of batch materials, notably in a submerged combustion melter: [0200] 40 wt % of scrap fibers (batch material 1); [0201] 2 wt % steel slag (batch material 2); [0202] 58 wt % basalt (batch material 3); [0203] 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.

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 59.5 15.0  18.0  3.0 1.0 0.5 1.5 0.5 1.0 material 1 Scrap fibers Batch 11.3 5.3 22.8  5.6 47.2  6.7 0.6 0.5 material 2 Steel slag Batch 48.1 15.4  9.2 8   2.1 10.7  3.4 2.2 0.7 0.2 material 3 Basalt

[0204] As it can be seen, the first batch material has a composition significantly different from the composition of the melt or mineral fibers produced.