Method for recycling water resulting from a method for producing a mat of mineral fibres
The invention relates to the field of materials based on mineral fibers, in particular mineral wool such as glass wool or rock wool. More specifically, the present invention relates to a method and a device for recycling the water recovered in a fiberizing and shaping method when using a specific acid binder based on monomeric polycarboxylic acid, or a salt of such an acid.
1 . A method for reducing the corrosion of equipment during production of a mineral fiber mat, said method comprising:
fiberizing fibers and then bonding them with the aid of an aqueous binder comprising at least one sugar selected from hydrogenated sugars, reducing sugars, and non-reducing sugars, and at least one monomeric polycarboxylic acid or salt thereof in a forming zone;
cross-linking the aqueous binder in an oven; and
washing the equipment in the forming zone with wash water that is continuously recycled in a first recycling loop and whose pH is adjusted to a value between 6 and 9 before being recycled to said forming zone along said first recycling loop,
the method further comprising washing fumes from the oven with water and recycling the fumes' wash water;
in a second recycling loop, separate from the first, a portion of the recycled fumes' wash water being transferred at intervals to a zone for preparing said aqueous binder, without adjusting its pH.
2 . The method according to claim 1 , wherein the pH value is adjusted with a base selected from an alkali metal hydroxide, an alkali metal carbonate, an alkaline earth metal hydroxide, and an alkaline earth metal carbonate.
3 . The method according to claim 1 , wherein the aqueous binder comprises at least one hydrogenated sugar selected from: erythritol, arabitol, xylitol, sorbitol, mannitol, iditol, maltitol, isomaltitol, lactitol, cellobitol, palatinitol, maltotriol, hydrogenation products of starch hydrolysates, and hydrogenation products of lignocellulosic materials.
4 . The method according to claim 1 , wherein the aqueous binder comprises at least one reducing sugar selected from: a monosaccharide and a disaccharide.
5 . The method according to claim 1 , wherein the aqueous binder comprises at least one non-reducing sugar selected from: disaccharides, trisaccharides, tetrasaccharides and pentasaccharides.
6 . The method according to claim 1 , wherein the monomeric polycarboxylic acid is selected from dicarboxylic acids, tricarboxylic acids, and tetracarboxylic acids.
7 . The method according to claim 1 , wherein a quantity of water equivalent to the quantity of wash water transferred to the preparation zone of said aqueous binder is introduced at intervals into the fumes' wash water.
8 . The method according to claim 1 , wherein the recycled fumes' wash water is filtered before being used for the preparation of the aqueous binder.
9 . The method according to claim 1 , wherein the aqueous binder comprises at least one hydrogenated sugar selected from: xylitol, maltitol, sorbitol, hydrogenation products of starch hydrolysates, and hydrogenation products of lignocellulosic materials.
10 . The method according to claim 1 , wherein the aqueous binder comprises at least one reducing sugar selected from: glucose, galactose, mannose, and fructose.
11 . The method according to claim 1 , wherein the aqueous binder comprises at least one reducing sugar selected from: glucose and fructose.
12 . The method according to claim 1 , wherein the aqueous binder comprises at least one reducing sugar selected from: lactose, maltose, isomaltose, and cellobiose.
13 . The method according to claim 1 , wherein the aqueous binder comprises a non-reducing sugar, which is sucrose.
14 . The method according to claim 1 , wherein the monomeric polycarboxylic acid is citric acid.