CS227787B1 - Method for preparing a cupola furnace charge - Google Patents

Abstract

The invention relates to the production of mineral fibers by melting raw material in a dome furnace. The purpose of the invention is to improve the uniformity of the melting process and to use solid fuel with small grain sizes for the melting process without requiring its strength and sharpness of sorting. According to the invention, this purpose is achieved by first preparing briquettes from fine-grained raw material and: solid fuel using binders and only then loading these briquettes into the furnace.

Description

The present invention relates to a method for preparing a cupola furnace in the manufacture of mineral fibers.

The melting of the mineral fiber raw materials in cupola furnaces is carried out by charging the furnace alternately with layers of raw material and solid fuel. Sometimes a combination of solid fuel with gas, or only gas, is used. The raw material is coarse-grained natural aggregate or coarse-grained waste slag or also agglomerated fine-grained material bonded by various binders in the form of briquettes. The heat generated by the combustion of fuels gradually heats the raw material and melts away from the surface and heats the melt to a temperature suitable for subsequent pulping. This method of production places high demands on the quality of solid fuel, which is usually coarse-grained high-grade coke or anthracite. Due to the method of preparation of the charge, it is mainly the strength and sharpness of sorting. At the same time, the method of feeding the fuel into the furnace does not guarantee a uniform distribution in the furnace and hence uniformity of melting of the raw material and hence homogeneity of the melt. The shape unevenness of roughly crushed raw material is also adversely affected. This drawback is particularly evident in gas-fired furnaces, where, in addition to careful preparation of the raw material by crushing and sorting, it is necessary to control the furnace charge to ensure an even distribution of gas and combustion products throughout the cross-section of the furnace.

These drawbacks are overcome by the process of preparing a charge according to the invention, which consists in that briquettes are first prepared from the fine-grained raw material and solid fuel by means of binders and only these briquettes are charged into the furnace.

An advantage of the process according to the invention is that it allows the use of solid, small grain size fuels for the melting process without requiring its strength and screening sharpness. The solid fuel according to the degree of homogenisation is equally distributed in the individual briquettes and

227 787 thus also over the entire cross-section of the cupola furnace, which provides a precondition for uniform melting of the raw material in the furnace. In addition, the fuel is in direct contact with the feedstock throughout the furnace space, which contributes to the intensification of the melting process.

The particle size of the solid fuel depends on the size of the briquettes, the calorific value of the fuel used and its other properties.

It is also possible to use very fine-grained fuel, which in turn allows the use of fine-grained basic raw materials. When the mixture is mixed sufficiently, the fuel particles are distributed evenly throughout the briquette volume. Different types of binders can be used to combine the individual grains, which are mixed with the raw material simultaneously with the fuel. After mixing the individual components, briquettes of the required shape and size are prepared from the mixture thus prepared. The finished briquettes containing the raw material with fuel are charged into the dome of the cupola furnace, where they are usually dried first and gradually heated until the briquette fuel burns out, thereby melting the raw material. The following overview lists four possible briquette compositions containing, in addition to raw material and binder, solid fuel

Example raw material, fuel 1 2 3 4

(a) anthracite, grain size 1-3 mm, net calorific value 30 000 kJ / kg

b) coke, grain size 1-3 mm, calorific value 27 000 kJ / kg ² · PpJAgg.

a) inorganic (cement modified)

b) inorganic (marlstone)

(c) organic

3 · Raw material

(a) 0-8 mm natural debris

(b) mineral wool wastes, grain size 0-8mm

TOTAL

20%

20%

21%

15%

4o%

35%

30%

100%

21%

15%

8%

64% 72% ιδδ% ϊοσ%

227 787

The cupola furnace can only be charged with briquettes with the appropriate fuel content or in combination with the fuel as before, with the use of a small fuel component resulting from its crushing during transport and storage which would otherwise not be used for the melting process in the cupola furnace.

Claims (3)

SUBJECT OF THE INVENTION 227 787 Process for preparing a dome furnace charge in the production of mineral fibers, characterized in that briquettes are first prepared from the fine-grained raw material and solid fuel by means of binders and only these briquettes are charged into the furnace. 2. A process for preparing a cupola furnace according to claim 1, characterized in that coarse briquettes of high quality coke are added to the briquettes. 3. A method according to claim 1, characterized in that the briquettes are prepared from a mixture containing 30 to 75% by weight of natural aggregate and / or mineral fiber waste crushed to a particle size of up to 20 mm, 5 to 40% inorganic. or an organic binder and up to 30% solid fuel ground to a particle size of up to 5 mm.