DE3704140A1 - Process for the manufacture of reactive products - Google Patents

Abstract

For the manufacture of reactive products for burdening and smelting, in particular in the electric furnaces, the solid raw materials, corresponding with respect to their chemical purity and composition to the requirements of the metal product to be manufactured, are first ground to a fine grain size. This grinding is preferably taken down to a grain size of < 0.5 mm. The fine-grained raw materials are then mixed with a cold binder which is partially dissolved in a fluid and partially in the form of a dry powder. A binder mixture can also be used in place of a cold binder. The mixture thus prepared is then agglomerated to give shaped pieces which are subsequently treated thermally up to a maximum temperature of 1000@C. The individual weight of the shaped pieces is about 3 to 10 g. An impregnation of the mixture or of the shaped pieces can be carried out before or after the thermal treatment.

Description

The invention relates to a method for producing reactive products for filling and smelting, esp especially in electric ovens.

Is known for. B. the Si metal production in an electronics derschachtofen. This is loaded with a coarse, loose piece of oil made from numerous raw material components. The feed is non-uniform both locally and in terms of quantity. The consequence of this is an uncontrolled erosion of the individual Möller components and the resulting very high material losses. The expensive Reaktivkoh lenstoffe required for smelting can only be used to a limited extent, since they burn off for the most part on the furnace surface. The SiO gas generated during the work process can pass the Moller unused, consequently reacts with O ₂ to SiO ₂ above the furnace bed and is entrained by the exhaust gas as silica dust. The environmental impact is therefore high. This fact is reinforced by the fact that the abrasion of the carbons used during charging and operation is also carried away by the exhaust gas stream.

The electricity requirement is high because of the inevitable bar uneven grain and raw material mixing ratio The electrical resistance is comparatively low is low and therefore an undesirable unimpeded current flow to the furnace walls can take place. The raw material capacity actions can only be used imperfectly. It can only an upper and lower grain belt can be used. Oversize should be broken. Fine particles either burn unused or must be deposited after screening, to avoid oven clogging due to fine grain.

So far, it cannot be prevented that some of the Raw materials become plastic before the melting zone or even burst. This peculiarity has the consequence that initially gas impermeable layers are formed, which subsequently in the event of a gas breakthrough to extremely dangerous oven erup ions leads. It also increases operational safety reduced that the raw materials used, caused by different specific weights, when going to the oven Part to be segregated and in this way nests with unsuitable form stoichiometric conditions. The furnace through sentence is unsatisfactory, since the reaction processes of the comparatively small specific surfaces of the rough lumpy raw materials are dependent.

Finally, it should be noted that through the so far unavoidable irregular oven operation this also sturge due and very difficult to control.

The invention is based, in the preamble to improve the method described in claim 1, that with an increase in furnace throughput and increase operational security the need for raw materials and reactive carbon is reduced, the raw material capacities better are usable, the electricity requirement is reduced and the environment pollution by lowering the fly ash proportion.  

According to the invention, this object is achieved in the Features listed in the characterizing part of claim 1.

The need for raw materials can now be reduced because the Moldings formed from various raw materials in entire furnace a homogeneous, homogeneous stoichiometric to form an optimal moller. Because the previously easily combustible Carbons now in the individual molding together with the ores involved in a regular homogeneous distribution there is also less need for expensive reactive carbon. In addition, the binder Combinations of porous and reactive cracking structures in the furnace in the moldings, which are the original portions of the reak Complement the charcoal.

The environmental impact is significantly reduced, as this ent most of the SiO gas already in the moldings at the often existing contact surfaces with carbon as well as C and Si intermediates. They also have Shaped articles with a higher degree of uniformity Strength than most of the coals previously used fabrics. The electrical resistance of the moldings is through the built-in reactive carbons large. Also guarantee the moldings have constant resistance throughout the furnace ratios, so that no irregular and undesirable hindered current flow to the furnace walls can take place. The This significantly reduces electricity consumption.

The existing raw material capacities can do much better be used than before. The reason for this is that for the production of the moldings all grits, if necessary after previous grinding can be used.

The constant molding composition enables one even furnace operation and thereby an increase in Operational safety. This will be further improved sert that a high temperature by appropriate binders  door strength can be achieved. The moldings therefore disintegrate only in the melting zone. Compacting can do this fig with just one broadband binder combination that possibly even from only one binder of different consistencies zen can exist, or two-stage with a binder comm bination made from at least one binder for the low temperature range (green strength) and min least a binder for the high temperature range (furnace stability) are driven.

This can increase the furnace throughput be that the composition of the moldings from fine or finest grits a significant increase in spec fish reaction surface causes. So the Reak processes in the moldings and remain not just on the comparatively small specific waiters limited area of the previous coarse raw materials. The moldings also remain in the melting zone stable and still contain process accelerators Reactive carbons made from the originally attached Reactive carbons and the highly reactive cracking products of the binders exist.

Precise control of the furnace cycle is therefore possible because the moldings precisely meet the specific furnace requirements conditions such as Möller weight, furnace geometry, gas passage, necessary reactivity, electrical resistance, etc. Mix composition and the binder selection can be put.

The moldings according to the invention can also be inexpensive permanent weather and storage stability. This is by impregnating the moldings or the Mixing possible, what according to claim 2 before or after thermal treatment can be carried out. Hereby will also reduce quality because it reduces stability Avoid water absorption of the moldings.  

The thermal treatment of the moldings at temperatures up to 1000 ° C has the advantage that the water Absorbability of the water-soluble binders canceled becomes. This can result in indirect impregnation of the moldings by converting the binder, i.e. without the actual impregnation addition of funds can be achieved.

Furthermore, such treatment can be mixed or sprayed impregnant in an optimal effect stood to be moved.

In addition, the moldings can be dried, sintered or to reduce the volatile content be melted or coked.

Overall, this is a surprisingly simple process Provision of reactive products for filling and ver smelting, especially in electric furnaces, which essentially all application-technical conditions and product-specific requirements of the metal producers in electrometallurgy. It becomes possible for the first time all previously used raw materials in any Mixture in a molding that is stable at all temperatures to unite. This leads to electrometallurgical production oven not only on favorable conditions overall, son also to a metal production process in which after Laying in the stable until its chemical dissolution Formling an even more extensive process and product optimization tion is recorded.

The addition of the impregnating agent can be done either with the Features of claim 3 or with the features of the Say 4 take place.  

With the features of claim 5, it is also possible slag-forming processes to the extent necessary To take into account or in the case of silicon carbide and corundum generation by installing reaction nuclei, e.g. B. from Semi-products like SiC.

The scope of DE-OS 35 06 439 is already the manufacturer development of moldings known. This concerns everyone but a targeted two-stage briquetting, that is the production of a pure carbon blank.

Below are some examples of the types of moldings whose application areas are listed.

• 1. FeSi production % By weight Anthracite: 5 green petroleum coke: 15 Lignite coke: 15 Scrap iron / iron ore: 5 Quartz: 50 Strength: 3 Bad luck: 6 Impregnation agent: 1
• 2. Si metal production wt .-% green petroleum coke: 24 peat coke: 5 charcoal: 4 quartz: 55 lignins and pitches: 10 nucleating agents (mixture of
  SiC and Si metal grains): 1.5 Impregnation agent: 0.5
• 3. SiC production % By weight green petroleum coke: 24 Quartz: 60 Molasses: 15 Nucleating agents (SiC grains): 1
• 4. Phosphate production % By weight Peat coke: 5 green petroleum coke: 13 Quartz: 15 Calcium phosphate: 60 Cold binder: 6 Impregnation agent: 1
• 5. Cupola % By weight Hard coal coke: 4 Low Ash Coal: 3 green petroleum coke: 10 Iron ore / ferrous scrap: 70 Lignins: 13

Claims (5)

1. A process for the production of reactive products for filling and smelting, in particular in electric furnaces, characterized in that first of all the solid raw materials corresponding to the requirements of the metal product to be produced in terms of their chemical purity and composition are fine grains, preferably to a grain size <0 .5 mm, ground and then mixed with the addition of a cold binder or a binder mixture, partly dissolved in a liquid, partly in the form of a dry powder, and then the mixture is agglomerated into shaped articles, preferably with unit weights of about 3 to 10 g, which are then thermally treated up to a maximum temperature of 1000 ° C. 2. The method according to claim 1, characterized records that before or after the thermal treatment impregnation of the mixture or the moldings is carried out. 3. The method according to claim 1 or 2, characterized ge indicates that when mixing the vermah raw materials and the cold binder or binder an impregnating agent is added.   4. The method according to claim 1 or 2, characterized ge indicates that an impregnating agent on the dried moldings is injected. 5. The method according to claim 1, characterized records that nucleating agents, flux or catalys goals when mixing the raw materials with the cold binder or be added to the binder mixture.