Method for recycling material when making a mineral melt

1. A method of making a mineral melt by burning combustible material in the presence of a particulate mineral material and thereby forming a melt, the method comprising the steps of:

supplying a particulate mineral material and a first portion of a waste material into a conduit of a heat exchange system, wherein the first portion of the waste material is a first waste mineral wool;

preheating the supplied particulate mineral material and the first waste mineral wool in the heat exchange system;

injecting a fuel, a combustion gas, the preheated particulate mineral material and the preheated first waste mineral wool into a circulating combustion chamber through an inlet conduit, and combusting the fuel in the circulating combustion chamber thereby melting the particulate mineral material and the first waste mineral wool to form a mineral melt and generating exhaust gases;

separating the exhaust gases from the mineral melt, collecting the mineral melt and passing the exhaust gases upwards through an exhaust pipe to the conduit of the heat exchange system; and

supplying a second portion of the waste material with a water content between 5 and 25% by weight directly to the inlet conduit, wherein the second portion of the waste material is a second waste mineral wool.

2. The method according to claim 1 , wherein the heat exchange system comprises a pre-heater cyclone which is being fed via said conduit of the heat exchange system with the supply of the particulate mineral material and the supply of the first waste mineral wool for pre-heating before exiting the preheater cyclone through a supply conduit into the inlet conduit for injection into the circulating combustion chamber, wherein according to the method, a third portion of the waste material is supplied to the supply conduit.

3. The method according to claim 2 , wherein the waste material supplied in the third portion is fly ash.

4. The method according to claim 2 , wherein the second waste mineral wool is supplied directly to the inlet conduit downstream of the supply conduit.

5. The method according to claim 1 , wherein the second waste mineral wool is mixed with fly ash before it is supplied directly to the inlet conduit.

6. The method according to claim 1 , wherein the first and second waste mineral wool is milled and has a water content of 10-15% by weight prior to being supplied.

7. A method of making a mineral melt by burning combustible material in the presence of particulate mineral material and thereby forming a melt, the method comprising the steps of:

injecting a fuel, a particulate mineral material and a combustion gas into a circulating combustion chamber through an inlet conduit, and combusting the fuel in the circulating combustion chamber thereby melting the mineral material to form a mineral melt and generating exhaust gases;

separating the exhaust gases from the mineral melt, collecting the mineral melt and passing the exhaust gases upwards through an exhaust pipe to a conduit of a heat exchange system; and

supplying a particulate mineral material and a first portion of a waste mineral wool into the conduit and pre-heating the supplied particulate mineral material and first portion of waste mineral wool in the heat exchange system, and

supplying a second portion of waste mineral wool with a water content between 5 and 25% by weight directly to the inlet conduit,

wherein approx. 20% of the total waste mineral wool is supplied into the conduit for pre-heating and approx. 80% of the total waste mineral wool is supplied directly into the inlet conduit.

8. The A method of making a mineral melt by burning combustible material in the presence of particulate mineral material and thereby forming a melt, the method comprising the steps of:

injecting a fuel, a particulate mineral material and a combustion gas into a circulating combustion chamber through an inlet conduit, and combusting the fuel in the circulating combustion chamber thereby melting the mineral material to form a mineral melt and generating exhaust gases;

separating the exhaust gases from the mineral melt, collecting the mineral melt and passing the exhaust gases upwards through an exhaust pipe to a conduit of a heat exchange system; and

supplying a particulate mineral material and a first portion of a waste mineral wool into the conduit and pre-heating the supplied particulate mineral material and first portion of waste mineral wool in the heat exchange system, and

supplying a second portion of waste mineral wool with a water content between 5 and 25% by weight directly to the inlet conduit,

wherein the heat exchange system comprises a pre-heater cyclone which is being fed via said conduit with the supply of mineral material and the supply of waste mineral wool material for pre-heating before exiting the preheater cyclone through a supply conduit into the inlet conduit for injection into the circulating combustion chamber, wherein according to the method, a third portion of waste material is supplied to the supply conduit,

wherein the waste material supplied in the third portion is fly ash,

wherein approx. 50% of the total fly ash is supplied in the supply conduit and approx. 50% of the total fly ash is mixed with the waste mineral wool prior to being supplied directly into the inlet conduit.