CS203129B2 - Method of hardening slag - Google Patents

Abstract

1492732 Ferrochromium slag HUTA SIECHNIEE 7 Oct 1976 [7 Oct 1975] 41633/76 Heading C7D To prevent the disintegration of the cooled and solidifed slag formed during the production of ferrochromium by the reduction of chromium ore with lime and ferrosilicon, B203 is added to the charge, resulting in a weather resistant slag which is useful as a building material. The B203 may result from the residues obtained in the production of boric acid and/or borax which contain 2-7% B 2 O 3 , or from boron ore, which contains more than 30% B 2 O 3 . If the residues are used, the lime used to produce the ferrochromium may be reduced by the same amount as the lime contained in the boric acid/borax residues, thus giving a further saving in costs.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for strengthening slag arising from the production of ferochrome.

In prior art processes, slag produced in the production of ferroochooma and quantitatively corresponding to approximately 3/4 of the batch is cast into a ladle. When it cools, it forms an irregular block. These blocks of Etruscan are transported to the heap, where they are tipped and stored. Over time, the blocks disintegrate into dust, which pollutes the air around the smelters because it is gentle, carried away from the heap by the wind, and scattered around. The amount of dust from one plant is, for example, approximately 4,000 tonnes per year, thus contaminating the plant environment with dust so much that plant life is impossible. Partially the dust in the form of chromate does not solve the problem, since it reaches only a few percent and the rest of the slag goes in the same way as the heap.

All pokiusi bind the chord after its disintegration with cement or jirýfai means or ways, failed.

It is an object of the present invention to provide a process by which ttrutane obtained in the production of ferro-. of chromium, permanently joined.

The problem has been solved and the disadvantages of the prior art have been reduced by the method of reinforcing the grinder according to the invention resulting from the production of ferrochromes by melting in an electric furnace from a batch containing approximately 43.4% chromium ore, 45.6% lime and 10.9% ferrosilicon, the principle of which is to add boron trioxide B ₂ ° 3 to the charge during the melting of the ferrochromium ^{in the} mhc range of 0.14% by weight, calculated per charge.

Preferably, boric oxide Β ₂ θ3 is added in the form of dried chemical wastes generated by the production of boric acid and / or borax containing 2 to 7% by weight of boron oxide BgOy

The boron oxide may also be added in the form of boron ore, preferably containing over 30% by weight of boron oxide BgO 3.

The wastes may be added in an amount of 1/20 to 1/50 by weight of the feed, the amount of lime added to the feed being reduced by the amount of lime contained in the added waste from boric acid production H ^ BOj and / or borax Νβ ^ Β ^ Ογ.

Boric ore is preferably added in an amount of from 1/200 to 1/500 by weight of the feed.

By utilizing the process according to the invention, not only the above-mentioned objective of the solution, i.e. the binding of the ferrochromic etruscus tube, is strengthened, but economically wastes arising from the production of boric acid and borax are utilized. The amount of lime consumed in the batch to produce ferrochromium is also reduced. The use of the invention also avoids dusting around the ferrochromium smelters. The experiments confirmed the full applicability of the method of the invention. The slag acquires a solid form and has no tendency to disintegrate. In the process according to the invention, two wastes are used economically, namely chemical wastes obtained in the production of borax and slag in the production of ferrochrom, while owing to an early reduction in the consumption of feed material in the production of ferrochrom, i.e. lime. Stable slag can be used simultaneously as a building material.

and

Examples

Example 1

6,000 kg of chromium ore, 6,300 kg of lime, 1500 kg of ferrosilicon and 20 kg of boron oxide BgOy were used as a batch for the production of one batch of ferrochromium.

Example 2

6,000 kg of chromium ore, 6,000 kg of lime, 1,500 kg of ferrosilicon FeSi, and 450 kg of dried boric acid and / or borax production wastes were used as a batch for the production of one batch of ferrochromium, which contained about 5% boric oxide and approx. 60% of the lime compounds that were transferred to the Etruscan during the production of ferrochromium. Conventional melting of ferrochrome was performed in the furnace, after which the slag and ferrochrome were tapped.

Example 3

For example, the following slag composition was used to solidify the slag using boric ore: 6,000 kg of chromium ore, 6,300 kg of lime, 1,500 kg of ferrosilicon and about 45 kg of boron ore containing over 30% boron oxide BgOy

When utilizing the method of the invention, no changes in the production of ferrochromium and no changes in the furnace design or the furnace charging method are required. Slag tapping is also carried out in the same manner as before. The invention solves the fundamental problem of ferrochromium production, which has not been successfully solved for many years, i.e. the problem of avoiding the disintegration and dusting of slag resulting from ferrochromium production and thereby pollution of ferrochromium as well as waste after borax and / or boric acid production. and a significant amount of building material is obtained.

AND

SUBJECT OF THE INVENTION

Claims (5)

SUBJECT OF THE INVENTION CLAIMS 1. A process for the consolidation of slag arising from the production of ferrochrome by melting in an electric furnace from a batch comprising approximately 43.4% by weight of chromium ore, 45.6% by weight of lime and 10.9% of mono -ootic ferrosilicon, characterized in to a charge of boron trioxide B ₂ ° 3 in an amount of 0.14% hmoonoot calculated on the charge. * 2. A method of fixing slag according to claim 1, characterized in that boric trioxide VdOD is added in the form of dried chemical wastes produced in the production of boric acid and / or borax and containing from 2 to 7%. boron oxide B ^ Oy 3. A method according to claim 1, characterized in that the boron oxide is added in the form of boron ore, preferably containing over 30% of boron oxide. 4. A method according to claim 2, characterized in that the wastes are added in an amount of from 1/20 to 1/50 of the Uoternal portion of the charge, the lime addition to the charge being reduced by οοο. ίν! of lime contained in the added waste from the production of boric acid HyBOy and / or borax Νθ ,, Β ^ Ογ. 5. The method of consolidating slag according to claim 3, characterized in that the booite ore is added in οοο ^ ίν! from 1/200 to 1/500 by weight of the feed. Severography, n. P. Plant 7, Most '