WO2016004913A1 - Method and device for processing iron silicate rock - Google Patents

Abstract

The method is used to process iron silicate rock. At least one component is at least partially removed from the iron silicate rock. At least one component that is different from iron is thus removed from the iron silicate rock. The processed iron silicate rock is used for the production of pig iron or steel. The device for utilizing the processed silicate rock is designed as a device for producing pig iron or steel.

Description

 Method and device for processing iron silicate stone

The invention relates to a process for the treatment of iron silicate rock, in which at least one component is at least partially removed from the iron silicate rock.

The invention also relates to a device for processing processed iron silicate rock.

The iron silicate rock is currently being used almost exclusively mechanically. The iron silicate stone is produced as slag during the smelting of copper ores.

The iron silicate rock is currently being poured into molds, for example, and the resulting moldings are used for bank attachment. Also is already a granulation of iron silicate stone known. Coarse granules are used for example as gravel for railway embankments. Finer granules are used in sandblasting.

Iron silicate stone consists essentially of its weight fractions of iron, silicon and oxygen. In addition to the iron content, the iron silicate rock also contains minor elements, for example copper, lead, arsenic, nickel and / or zinc.

The smelting of copper ores (mainly chalcopyrite) produces large amounts of slag. Based on the amount of valuable metal-containing feed material, 600 kg slag / t ore concentrate in the copper industry generates about three times the amount of slag compared to the iron and steel industry.

Slag cleaning is already in operation worldwide with the main goal of increasing / maximizing copper output. There are two approaches to the process: a) pyrometallurgical - in the electric furnace or in the oil / gas fired Teniente furnace. In this case, a molten treatment of the slag by gravimetric phase separation of the slag / Kupfersteingemisches. A coke cover (reductant) has the main task of preventing oxygen access to the melt. b) Hydrometallurgical slag flotation. After solidification of the slag, a grinding process and then the flotation of sulfidic copper particles. The result is a concentrate that can be returned to the primary process.

The residual copper contents of these processes are approximately 0.4-0.8% and both processes are not designed for the metallurgical removal of further impurities. The resulting slag product (whether pyro- or hydromechanical) has a problem: there is almost no commercial application and the available applications are of little value added. The largest share of copper slag produced worldwide (approx. 15 million t / a) is therefore landfilled.

The object of the present invention is to improve a method of the aforementioned type such that an improved economy is provided.

This object is achieved in that at least one component other than iron is at least partially removed and that the processed iron silicate rock is used for the production of steel pig iron.

Another object of the present invention is to construct a device of the initially mentioned type such that an improved economy is achieved.

This object is achieved in that the device is designed as a device for the production of pig iron or steel.

The metal content of copper slags has not been used (neither the non-ferrous metals nor the iron content). With a slag amount of 700kt / a, this corresponds to an iron content of 280kt / a. The slag is already liquid and therefore only relatively little energy has to be expended to carry out the process. Therefore, the present invention is based on the approach to remove the non-ferrous metals from the slag product and to use the remaining slag product (containing slag formers Si, Ca, Mg, Al and Fe as oxides) as raw material for the production of pig iron or steel.

This downstream process allows the upstream process steps more flexibility in the processing of copper raw materials. The complexity of these raw materials in terms of their composition will continue to increase in the future, which is due to the fact that the existing copper ore deposits are poorer. In addition to economically interesting impurities (processing huts For example, as regards the steel industry, especially Zn and steel pests such as S and P are important parameters in terms of the steel industry. In addition, of course, the copper application is crucial. The newly developed process according to the invention covers these requirements and pursues the goal of the so-called "zero-waste metallurgy", ie all products resulting from the production process are further processed.

Below is a point-like description of the main process steps in carrying out the preparation of iron silicate rock according to the invention

process description

Starting Materials:

^■ Iron silicate rock, fayalite - (copper slag from primary copper production)

^■ Reducing agent (solid - coke, coal, gaseous - CO, H2, Fe)

^■ collector metals (Cu, Fe)

^■ Electrical energy

^■ natural gas or natural gas decomposition products

^■ air / oxygen

^■ Circulation products from the copper and steel industries (eg, desserts, smoothing, fly ash, food, metal phases) or slags Process temperature:

■ 1300 - 1600 ° C (previously optimal process temperature at 1400 ° C) Aqgreqat (e):

■ E-oven (rectangular, treatment zone, rest zone, tapping executed as overflow, inlet via gutter system, gas input through soil rinsing)

■ Closed AOD converter with floor flushing process control:

^■ discontinuous

^■ Continuous (preferred, depending on the current investigations if actually feasible)

^■ Multi-level - necessary! Enerqiezuführung:

^■ electric oven - electric (very low oxygen potentials adjustable)

^■ AOD converter - gas-fired (stoichiometric combustion required (□ <1, preferably 0.8-0.9; disadvantage - oxygen potential increased compared to the electric furnace) dwell time:

^■ not yet finally determined; approx. 2-6 h Products:

^■ slag product (s) - fayalite product, magnetite product

^■ flue dust

^{■ Metal} alloy

In the drawings, embodiments of the invention are shown schematically. Show it:

1: a schematic representation of the process flow, FIG. 2: a table for the specification of the starting material,

Fig. 3: A table for the specification of the slag product from the process.

Fig. 1 shows a schematic representation for carrying out the individual process steps. In particular, the process sequence in the deep reduction of iron silicate rock to a fayalite or magnetite product is shown as a raw material for use in the iron and steel industry. The slag from the primary copper process is preferably charged liquid in the Tiefred uktionsprozess. The liquid slag preferably has a temperature in the range of 1200 ° C to 1350 ° C. Typical is a temperature value of about 1260 ° C.

Alternatively, it is also intended to work up slag heaps by the process according to the invention. In comparison to the processing of liquid slag, however, a higher energy requirement is caused here, since first a melting down of the solid material is required. A typical analysis of the feedstock is shown in the table of FIG.

The aim of the process is to separate the precious metals contained in it by selective reduction of the iron. The iron remains bound to silicon and / or oxygen as a fayalite product (Fe 2 SiO ₄ ) or magnetite product (Fe 3 O ₄ ) for further use as a feedstock in the iron and steel industry. This product contains other oxides of Ca, Mg or Cr as impurities. The specification for the product can be found in the table according to FIG. 3.

During the heating up to the preferred process temperature of 1400 ° C, the entry of oxygen must remove the residual sulfur present from the system so that the subsequent reduction period can be carried out efficiently. By adding max. 7% solid carbon based on the amount of slag is covered in the molten bath and protected against further oxygen access. The CO / CO2 ratio of the process atmosphere must be adjusted so that it does not exceed an oxygen potential of 10 ^"12 atm. In this phase, the volatile components of the slag volatilize and leave the process with the exhaust gas The obtained fly ash has a composition of about 40-60% Zn, 10-20% Pb and <10% As and can be used as a raw material for the zinc production eg in the so-called rolling process.From the example considered here An annual tonnage of 700,000 1 is to be expected with a flow rate of about 20,000 tonnes. The copper content after this process step is still about 0.2-0.3% Cu. For the selective separation of copper and iron, carbon monoxide is introduced as a reducing agent via rinsing stones arranged on the bottom. The advantage of soil flushing lies in the much lower required gas velocity compared to a lancet purging. This leads to an intensive mixing between slag, metal and gas phase. The reduction takes place at the phase interface gas / slag according to the reaction equation CU2O + CO - 2Cu + CO2. The metal drops formed are very fine (max 20 pm) and must be separated from the slag phase in a calming zone by density separation.

Depending on the further processing, the mineralogy of the slag product can be adapted for the respective application. If the product is to be used, for example, directly in the blast furnace, the fayalite phase obtained is sufficient. For use above the blast furnace, the pre-treatment in the sinter plant is necessary. The melting range of fayalite (about 1180 °) is too low for this and would lead to problems in processing. Therefore, the adjustment of the manganese content in the finished product is necessary. By adding a defined amount of oxygen, this ratio can be adjusted according to the customer's requirements. The oxygen can be added not only in From oxygen gas, but also in the form of intermediates serving as oxygen donors, such. B. Fe2O3 dust from the steel industry.

Claims

Patent claims 1. A process for the preparation of iron silicate rock, wherein from the iron silicate at least one component is at least partially removed, characterized in that at least one component other than iron is at least partially removed and that the processed iron silicate rock is used for the production of pig iron or steel. 2. The method according to claim 1, characterized in that the iron silicate stone is processed in a liquid state. 3. The method according to claim 1, or 2, characterized in that the iron silicate rock is treated at a temperature of about 1300 ° C to 1600 ° C. 4. The method according to any one of claims 1 to 3, characterized in that a reducing agent is supplied during the treatment. 5. The method according to any one of claims 1 to 4, characterized in that the processing is carried out in several stages. 6. The method according to any one of claims 1 to 5, characterized in that during the treatment at least temporarily oxygen is supplied. 7. The method according to any one of claims 1 to 6, characterized in that the treatment is carried out within an electric furnace with soil rinse. 8. The method according to any one of claims 1 to 7, characterized in that a reducing agent is supplied during the treatment. 9. An apparatus for the treatment of iron silicate rock, characterized in that the iron silicate rock is processed in an oven having a supply device for a gas. 10. An apparatus for processing of processed iron silicate stone, characterized in that the device is designed as a device for the production of pig iron or steel. 11. The device according to claim 10, characterized in that there is a training as a blast furnace.