The best way to clean the slag in an electric furnace

 

(57) Abstract:

The invention relates to a cleaning method of a slag generated in an electric furnace in metallurgical processes with non-ferrous metals, in particular, the method relates to a semi-continuous method of cleaning. Under the new method in an electric furnace provided with at least two outlet openings of the slag, the bottom of which are located on the same level as the upper outlet in the furnace of conventional type which operates in a batch mode, and the second outlet is located above or at the height of the inlet, or just slightly below it. The invention provides a reduction in the processing time of the slag. 6 C.p. f-crystals.

The present invention relates to a method of cleaning slag generated in an electric furnace in metallurgical processes with non-ferrous metals, in particular, the method relates to a semi-continuous method of cleaning.

In pyrometallurgical processes for obtaining Nickel and copper dried finely ground concentrate sulfide of Nickel and/or copper comes first, for example, in the oven for oplatki in suspension, which in addition to the concentrate to deliver air, oxygen or a mixture and the t two layers, the bottom, which is a matte containing the main amount of valuable metals, and the top is a layer of slag, which also contains small amounts of precious metals.

Oxidized slag produced from the furnace for melting in suspension or from a furnace of a different type, the first stage of the process contains valuable metals in such quantities that their processing will continue, mainly in an electric furnace where the slag restore using a reductant such as coke. When processing in an electric furnace precious metals bound in the slag phase, restore and separated to obtain a special phase of the matte under the layer of slag. And received Stein, and sent to waste recovered slag is removed through the respective outlet openings. In addition to copper and Nickel in the valuable metals are noble metals and other non-ferrous metals such as cobalt, in small quantities present in the slag.

In most cases, electric furnace used for processing slag, works in batch processing. Currently, the volume of the furnace, i.e. the size of the melt, and the time required for the process of melting on rasslablenie concentrate increases, then it is necessary either to increase the electric furnace, or also need to increase the performance of an electric furnace, for example, through the use of two electric furnaces or by replacing one furnace to another, larger, or by reducing recovery time and keeping melting, i.e., by reducing the speed of regeneration.

Have been developed various methods of increasing the performance of electric furnaces operating in a batch mode. In U.S. patent 3857700 method by which the cleaning of the slag improve by mechanical mixing. In U.S. patent 4110107 method by which carbon is used for recovering, introducing the molten slag, and in the method according to U.S. patent 4168156 attempts to improve slag removal by means of a flow of gas into the melt.

From U.S. patent 3666440 known way of cleaning the slag, which uses an electric furnace, operating in the continuous mode. In this type of furnace outlet to be sent after processing into a pile of slag provided on the same level as the inlet for the oxidized slag to be feeding into the furnace. The advantage of the furnace is the I on the surface, the advantage is that it merges the first. When running in batch mode outlet for slag is in the bottom part of the layer of slag, where cleaning of the slag perform last. On the other hand, the lack of a continuous method is that over time the main part of the furnace volume remains unused when the produced slag is poured from the furnace at a faster route. In the method according to U.S. patent 3666440 attempt to prevent this by means of wall construction, located at the feed end and passing down the length of the layer of slag.

The closest analogue is the patent SU 1766995. This patent relates to a conventional batch type cleaning method slag in an electric furnace. According to this method, first fill the furnace molten slag, coke and slag-forming Sandstone. The slag is deposited and then begin production. In the description of the patent says that solid copper-Nickel ore and scrap load simultaneously with the release of the furnace. This method is a common method of cleaning slag, although he was not specifically mentioned in this application. The only difference from the normal portion of the process is that is ardenia.

The objective of the proposed method is to reduce the processing time in the conventional batch process. This task is achieved by the fact that, as stated in the description, continue the flow of slag and simultaneously launch without a single phase deposition. This is possible because, as described, for example, in the prototype, the filling of the furnace takes 2.5 hours. According to the claimed method, the filling of the furnace continues after the furnace is filled with the top outlet open for a period of time corresponding to 20-50% of normal time to fill the furnace. The experience achieved in the use of this technique showed that a large part of reducing slag is in the upper part of the furnace, and it is discharged from the furnace through the first upper outlet. Therefore, in the proposed method, the time of deposition of the slag produced in this way can also be about two hours. In the proposed method the issue of recovered slag comes at a time when the other part of the slag in the furnace is precipitated and recovered. Due to the fact that some portions are produced simultaneously with the load, you can increase the total amount of servings in the normal duration of portions of the CEC is.

According to the method of the present invention the amount of servings, to be fed into the electric furnace can be increased by 20-50% compared to the way a conventional type which operates in a batch mode, however, the full processing portion remains the same.

The so-called semi-continuous electric furnace according to the present invention can operate in two alternative modes. When the upper outlet for slag made in the upper part of the furnace, at the same level there is also provided gutters, and if the oven has already been provided by the lower holes and gutters, they are also exploited. If the furnace is a new electric oven, there provide outlet openings and gutters as for batch and continuous slag removal.

The first method of the so-called semi-continuous process is as follows: cleaning of the slag in an electric furnace to start with, in order, by well-known methods, furnace, which is completely freed from the slag through a bottom outlet, start to fill by downloading the slag in an electric furnace in the usual manner boot slag from the furnace by aplace in a suspension or some other approach is e reductants, such as coke. The furnace is filled up to the maximum level of the melt, i.e., until the upper outlet opening provided at the level of the inlet, but after that filling another constantly, for example, during the period of time that corresponds to 20-50% of normal time to fill the furnace. Then begin draining through the top outlet of the furnace. Of course it is clear that at least the upper outlet for slag is made on the opposite side of the furnace in relation to the intake opening. The slag, which flows from the top through the upper outlet and is a slag, which was in contact with the reducing agent, since that time started to pour, because he had enough time to recover and deposition, and thus it has a low content of precious metals. Plums should be discontinued when the slag fed into the furnace, also begins to flow directly, as it is drained. Download from the melting furnace in an electric furnace stop, then electric furnace operated in the mode of the furnace in a batch mode, by reduction, sedimentation and sulfirovanie in the usual way. The final issue cleared W

In accordance with another so-called semi-continuous mode of operation upper outlet for slag, supplemented with a groove provided below the maximum surface level of the melt in the furnace, for example, at a distance equal to not more than 1/2, preferably about 1/3 of the height between the maximum level of the melt surface and the normal level is an outlet for slag. At the beginning of the oven operates in the above-described mode, i.e. the filling completely emptied furnace start by downloading the slag in the normal mode from the furnace to oplatki in a suspension or a suitable melting furnace, electric furnace, while the bottom outlet is closed. On the surface of the slag make some reducing agents such as coke. The furnace is filled up to the maximum melt level, but after that filling continuously continue, for example, during the period of time that is equal to approximately 20-50% of normal time to fill the furnace. Then begin draining through the top outlet of the furnace. After a period of time sufficient to drain, top opening closed, and raise the level of the surface of the slag up to the maximum. Discharging from the furnace start later period can be calculated as follows, to the surface layer of slag was an already recycled, recovered slag. After an appropriate period of time, i.e. the period of time required under normal working process in a batch mode, discharging slag end through the bottom hole.

As can be seen from the description above methods work, you can now use in an electric furnace, which is designed for batch mode, semi-continuous mode, and thus can be considerably increased the productivity of the furnace. The method according to the present invention are preferred, in particular when it is necessary to expand production, as the use of the above-described variations in the preferred mode even allows you to double the amount of slag compared to the conventional type of process in a batch mode. Therefore, using the above mentioned method, you can design a new oven setting to a smaller size than the previous designs of furnaces.

1. The best way to clean the slag generated in the iron making process with colored metal, which fed into the electric furnace slag under the action of a reducing agent formed of no the ACI slag, located at the maximum level of the melt, cut to release the slag in the bottom of the layer of slag, dedicated to producing the recovered slag, and cut to release the matte, which serves the slag in an electric furnace containing two holes for the release of the slag located at different heights, wherein the fill bake until the maximum level of the melt at the closed bottom of the hole to release the slag in the bottom of the layer of slag, restored allow the slag to flow through the top hole for the release of the slag, stop the flow of recovered slag from the upper outlet of slag, stop the flow of slag into the furnace and produce slag through a bottom outlet.

2. The method according to p. 1, characterized in that the upper cut to release the slag located at the height of the inlet.

3. The method according to p. 2, characterized in that the filling of the electric furnace slag continue even after the electric furnace is filled to a level corresponding to the maximum level of the melt, during the time corresponding to 20-50% of normal time filling the furnace, after which the filling is stopped.

4. The method according to p. 1, characterized in that the melt level is not more than 1/2 of the distance between the inlet opening and the bottom opening for release of the slag.

5. The method according to p. 1, characterized in that the upper cut to release the slag located at the distance of in the measurement of the maximum melt level is not more than 1/3 of the distance between the inlet opening and the bottom opening for release of the slag.

6. The method according to p. 4 or 5, characterized in that the filling of the electric furnace slag continue even after the electric furnace is filled to the level of the upper outlet, during the time period corresponding to 20-50% of the normal period of filling of the furnace, after which the filling stop, the top outlet cover and raise the surface of the slag to the level corresponding to the maximum melt level.

7. The method according to p. 1, characterized in that the recovered slag discharged from the furnace first through the upper outlet, and then through a bottom outlet.

 

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