LT6007B - Coke waste briquettes and producing method - Google Patents

Abstract

The invention relates to the construction industry, specially, to production of mineral wool products. When mineral wool technology melted in shaft type melting assembly, should be used solid fuel (coke), a fraction of which of more than 50 mm, therefore coke is sieved, separated finer fraction. In this way, the coke waste is produced which can’t be used for fusing load in low oven. Coke waste is recycled briquetting them, but compressive strength of briquettes shall not be less than 5.0 MPa. Invention goal is to increase in briquettes of coke waste compressive strength. The essence of the invention is by using of small coke waste (0-16 mm) and coarse coke waste (16-30 mm) fractions mixture increases the compressive strength of blocks, unnecessary their heat treatment also reduces of used amount of binder. Coke briquettes waste composition: small coke waste ( 0-16 mm) fraction of 58-78 %, coarse coke waste ( 16-30 mm) fraction of 10-30 %, cement 8 - 16% , water up to 8% in respect of dry materials.

Description

The invention relates to the field of construction industry, namely to the production of mineral wool products. When the mineral wool technology is used for melting the charge in a shaft-type smelting unit (low furnace), solid fuel (coke) with a fraction greater than 50 mm must be used, so that the coke is sieved and a smaller fraction separated. This results in coke waste that cannot be used in the melt furnace melt. The briquetting of coke waste and the use of briquettes in mineral wool technology to melt the charge in a low furnace reduces the amount of waste generated and the cost of energy resources.

It is known to produce briquettes from coke waste using organic binders - molasses (patent RU 2205204, 2003), lignosulfonate (patent RU 2298028, 2007), mineral oil (patent RU 2467058, 2011). GB 2185755 discloses that the binder is bitumen or another organic hydrocarbon-based binder. UA 79919 states that briquettes formed using molasses as a binder should be cured at 250-270 ° C. However, organic binder briquettes may not be used in a shaft-type smelter (low furnace) with a melting temperature up to 1500 ° C.

Patent RU 2330073 discloses a process for the production of briquettes, wherein the briquettes are made from coke or carbon and the binder is aluminum boron phosphate concentrate. The briquettes consist of Coke or Carbon (94-96)%, Aluminum Borophosphate Concentrate (2-6)%. It is stated that the use of such a binder does not require the curing of the briquettes by heat treatment. High values of compressive strength are achieved by electromagnetic pulse activation of the binder. The disadvantage of this method is that the binder is not suitable for use in mineral wool technology due to its chemical composition. In addition, 0.5-0.8 MW of power is required to generate electromagnetic pulses. The use of such equipment requires high energy costs.

Various types of cements can also be used to produce coke briquettes. Charles W. Olson (U.S. Pat. No. 4,078,902, 1978) discloses that briquettes are formed from fine coke fractions (80%), ash (I0%) and cement (I0%). The disadvantage of the patent is that the briquettes have to be heat-treated for 5 hours at 180 ° C, so this method of production requires high energy costs,

Patent patent RU 2334785 discloses a method of producing coke waste briquettes by adding an additional component, carbon, to the briquettes, in addition to coke. The composition of the briquettes is as follows: Coke waste 40-60%, Carbon 30-50%, Cement 5-12%. However, the manner in which the briquettes are formed and the compressive strength of the briquettes are not specified.

Compressive strength is an important property of coke waste briquettes. In mineral wool technology, raw materials with a compressive strength greater than 5.0 MPa must be used in the melting of the charge in the low furnace. Coke briquettes are known (EP0155439A1, 1984) for use in a low furnace. Coke 30-75%, cement 8-35% and mineral components 15-35% are used for briquette production. Fraction of coke used 2-25 mm. However, briquettes exhibit low compressive strength (1.25 to 3.90 MPa).

Patent RU 237308 discloses a briquetting method for coke waste which increases the compressive strength of the briquettes. Molded coke briquettes are coated with a layer of molten slag. The disadvantage of this method is that the slag has to be melted at high temperatures and therefore the production of briquettes requires high energy resources.

Patent RU 2266314 discloses a briquetting method for coke waste using coke waste from different fractions. This patent was chosen as an analogue. Coke waste with a fraction of (0-10) mm or (1025) mm can be briquetted. The binder used is various types of cement or Portland cement. The composition of coke briquettes is as follows: coke waste 60-95%, binder 5-40%, water up to 35% with respect to dry matter. Molded briquettes are cured by hot steam treatment. The obtained briquettes have a high compressive strength (30-47 MPa). The disadvantage of this patent is that high compressive strength values are achieved by hot steam treatment of briquettes, high binder content (up to 40%) and briquetting of coke residues with either (0-10) mm or (10- 25) mm. For these reasons, the cost of producing coke waste briquettes is increasing, and the production of briquettes requires high energy costs.

The object of the invention is to increase the compressive strength of coke waste briquettes. The object of the invention is achieved by using a mixture of fine coke waste fraction (0-16) mm and coarse coke waste fraction (16-30) mm for coke waste briquettes. The binder used is cement.

The essence of the invention is that the use of a mixture of fine coke waste (0-16 mm) and coarse coke waste (16-30 mm) increases the compressive strength of the briquettes, eliminates the need for heat treatment and also reduces the amount of binder used.

Coke waste briquettes used: fine coke waste (0-16) mm fraction 58-78%, coarse coke waste (16-30) mm fraction 10-30%, cement 8-16%, water up to 8% with respect to dry matter. The composition of the coke waste briquettes (dry matter) and the compressive strength of the briquettes after storage under natural ambient conditions are given in Table 1.

Table 6 Coke waste briquette composition and compressive strength

Forming blend Coke waste (0-16) mm,% Coke waste (16-30) mm,% Cement CEM II / A-LL 42.5R,% Compression strength, MPa 1 78 10th 12th 6.9 2 68 20th 12th 9.8 3 58 30th 12th 8.0

different types of cement can be used

Dry materials (fine and coarse coke fractions, cement) are mixed in a blender. Thereafter, water is added to the molding composition consisting of dry materials and the molding composition is stirred again. The vibropress mold is filled with the prepared molding compound. Briquettes are formed by vibrating and compressing the forming mixture. Molded briquettes are stored under natural conditions. The moisture content of briquettes after storage in natural conditions is 6-9%.

Coke briquettes are obtained as follows:

1. Crushing and screening of coke waste (fraction less than 50 mm), separation and storage of fine coke fraction (0-16) mm and coarse coke fraction (16-30) mm;

2. Dosing and mixing of dry substances;

3. Addition of water and preparation of forming mixture;

4. Briquette formation by vibration and compression;

5. Storage of briquettes in natural conditions.

Compressive strength determined in accordance with LST EN 772-1: 2011. Coke waste briquettes have good mechanical properties and can therefore be used in the melting of mineral wool feed in a shaft-type melting unit - low furnace. Briquetting of coke waste allows recycling of waste, protection of the environment, reduction of energy costs and increase of production efficiency.

Claims (5)

Definition of the Invention 1. Coke briquettes, consisting of coke waste and cement, characterized by the following composition: coke waste (0-16) mm fraction 58-78%, coke waste (16-30) mm fraction 10-30%, cement 8-16%, water up to 8% with respect to dry matter. 2. Coke briquettes according to claim 1, characterized in that the coke waste has to be crushed and sieved. 3. Coke briquettes according to claim 2, characterized in that the fine coke waste fraction (0-16) mm and the large coke waste fraction (16-30) mm are used for the briquettes. 4. Coke briquettes, characterized in that the forming mixture must be vibrated and pressed. 5. A process for the preparation of coke briquettes, which comprises crushing, sieving, mixing the materials and preparing the molding mixture, vibrating and pressing the briquettes, characterized in that the briquettes are cured under natural conditions.