CN1022846C - Copper smelting method and burner - Google Patents

Abstract

A burner for providing substantially complete combustion and uniform flame composition using a variety of fuels including low pressure gas and hydraulic fuel; and a method of using such a burner for melting copper cathodes in a vertical blast furnace.

Description

The present invention relates to burners capable of using a wide variety of fuels, including low pressure gaseous and liquid fuels, to provide substantially complete combustion and uniform flame composition; A method for the efficient and economical smelting of copper cathodes in a vertical blast furnace without introducing excess oxygen into the copper.

The need for burners capable of efficient heating and melting is a critical issue in the industrial sector, especially in today's environment of rising energy costs, decreasing energy sources and changing available fuels. The smelting of copper cathodes in a vertical combustion furnace is an example of the need for this type of new burner, which can use liquid fuels and Lanshui gas, carbonized water refining gas, improved natural gas, natural gas, coke oven gas, oil fuels such as gas, producer gas, and other natural and synthetic gases. The above-mentioned gaseous fuels are often taken directly from low-pressure city gas systems, and existing burners for high-pressure gas are not effective for the aforementioned applications, since booster devices are not always permitted.

Copper cathodes are produced commercially by electrolysis, as is well known in the art and discussed in U.S. Patent No. 3,199,977 (A.J.Phillips et al., published on August 10, 1965). This note is included by reference. This kind of cathode is industrially produced pure copper, generally about 2.54cm thick and in a flat rectangle shape of about 63.5 to 102cm, of course, it can also be produced according to larger and smaller specifications.

青法将此铜水中的硫与氧降低到可接受的含量。但从商品观点考虑，这样熔炼出的铜基本上受到破坏而不能予以使用，而必须通过一系列步骤进行再处理来形成新的阴极。这是一种费钱费时的做法。Although the copper deposited on the cathode is pure copper for industrial use, except for the common impurities that actually exist on the surface of the cathode or are included in it and the unavoidable small amount of electrolyte (sulfate), but due to their shape and physical properties, especially The copper cathode itself is generally not used due to the grain structure of the deposited copper. To bring it to a more useful form, it is necessary to melt the cathode and cast the molten metal into one or more semi-finished shapes, such as ingots, bars and rods such as blocks, ingots, bars, etc., cast into Shapes similar to the resulting finished products, such as plates, wires, tubes, and cast into many other commercially available products made from commercially pure copper. Furthermore, should the copper be contaminated during smelting with unacceptable levels of oxygen and sulfur in industrial production, it is of utmost importance that the molten metal be cleaned with

The green method reduces the sulfur and oxygen in this copper water to acceptable levels. From a commercial point of view, however, the copper thus smelted is substantially damaged and cannot be used, and must be reprocessed through a series of steps to form new cathodes. This is an expensive and time-consuming practice.

Therefore, it is critical that the burners used to smelt copper do not have, for example, harmful oxygen to contaminate the copper. Generally, the fuel-oxygen (air) mixture should be in such a proportion that the oxygen contained therein is insufficient to completely burn the fuel, and the flame formed for melting is a reducing flame. However, stringent requirements are imposed on such melting flames: despite the overall reducing nature of the flame, undesired oxidation effects due to the presence of unburned oxygen in the flame must be avoided. For most industrial applications, the predetermined reducing conditions are such that any oxygen infiltrated into the copper during smelting does not exceed 0.05% by weight of copper. The predetermined reducing conditions are preferably such that the amount of oxygen introduced into the copper water is less than 0.035% by weight of the amount of copper, and most preferably less than 0.01%.

等的美国专利以及4，536，152号美国专利（

等）中所介绍的燃烧器，都是专门设计成图1中所示的那种燃烧器形式，来提供前述那种均匀的还原火焰和熔炼的工业纯铜的制品。4，536，152号美国专利中所公开的内容已列入本说明作为参考。the above

et al. and U.S. Patent No. 4,536,152 (

etc.) The burners introduced in are all specially designed as the burner form shown in Figure 1 to provide the aforementioned uniform reduction flame and smelted industrial pure copper products. The disclosure of U.S. Patent No. 4,536,152 is incorporated herein by reference.

The prior art burner body 3 shown in FIG. 1 includes a mixing section 50 for combining the combustion stream and the oxygen-containing gas (air) stream into a combined stream and for introducing this combined stream into a flame holding section 51. . The burner body is also provided with a combustion section 52 mounted on a flange 53 which abuts against a shoulder 54 of the flame stabilization section 51 . An ignition rod 58 may be provided in the throat, while an electrically activated spark plug 59 of the usual type for igniting the combined flow is mounted alongside section 51 with the inner end of the plug abutting rod 58 . This combination of throat and rods 58 is designed to maintain combined flow combustion within combustion section 52, especially when fuel velocities are high. Section 51 is also provided with openings 69 and 70 for combined flow sampling.

Section 50 has an annular manifold portion 60 , sleeve 61 , bend or elbow 62 , orifice 63 and viewing port 64 fitted with transparent eyepiece 65 . Sleeve 61 abuts shoulder 66 and the left end of section 50, and in combination with annular portion 60 forms a manifold for passing the smaller of the two streams to be merged (usually the fuel stream) from conduit 36 through opening 67. Entering into the merging chamber 68; the entry of this smaller stream into the chamber 68 is controlled by the selection of the size of the opening 67 and its distribution around the perimeter of the sleeve. The larger stream is directed from duct 29 into chamber 68 through holes in plate 63 and bend 62 . Conduit 36 directs the smaller stream (fuel) into the burner body and is provided with valve 39 for controlling the amount of combustion delivered to the burner body at positive pressure. Conduit 36 is also provided with a diaphragm control valve 38 of the usual kind, and pipe 37 leads from within conduit 29 into the space above the diaphragm in this diaphragm valve to allow the air pressure in conduit 29 to pass to the diaphragm. The standard working pressure of fuel gas is 0.109MPa ~ 0.114MPa or higher.

When operating the burner body, the larger one of the two streams to be merged passes through a hole and enters the bend leading to the merging chamber. Measured by the method described in the patent.

Unfortunately, when using low pressure gaseous fuels and/or liquid fuels, the line pressure for such fuels is lower than that which exists in the burner body, which requires modification of prior art burners and special operating conditions, while in Industry is eager to come up with new burner designs suitable for use with these fuels.

SUMMARY OF THE INVENTION The present invention provides a highly efficient burner for smelting metal without appreciably contaminating the metal, capable of using a wide variety of fuels including low pressure and high pressure gaseous and liquid fuels. This burner is an improvement to No. 3,199,977 and No. 4,536, the burner described in U.S. Patent No. 152, and a suction mixing section is used to replace the pressure mixing section in the prior art burner , this suction mixing section allows the use of fuel at a pressure lower than, for example, the air pressure in the burner. For example, prior art burners generally operate at a pressure of 30.5 to 38 cm water pressure higher than air pressure. With the suction burner of the present invention, the fuel pressure can then be lower than the air pressure.

Another improvement is the provision of an eyepiece axially aligned with the mixing chamber of such a burner, which may be housed in the displacement rod used to form the suction orifice in the mixing section of the burner. The eyepiece preferably has a wide-angle observation objective lens for wide-angle observation of the chamber wall of the burner. A better embodiment is to use a telescopic observation instrument, which is preferably installed in the aforementioned displacement rod for focusing to certain parts of the burner and even the interior of the furnace.

Figure 1 is an enlarged longitudinal sectional view of a prior art burner system.

Figure 2 is a sectional view of the suction mixing section of the burner of the present invention.

The prior art combustor shown in Figure 1 and discussed above consists of many sections and sections. The improved burner consists in replacing mixing section 50 and bend 62 at or near point A of Figure 1 by mixing section 71 of the present invention shown in Figure 2 . The mixing section 71 can be installed at point A by threaded connection, flange or other mechanical seals. The tubing 37 leading to the diaphragm control valve 38 in Fig. 1 is preferably retained, but in a more preferred embodiment a similar tubing can be connected to the end of the mixing section 71 near point A. This fitting may be connected by a tee to fitting 37 to provide a pressure signal to valve 38 and provide enhanced control over burner operation.

As shown in FIG. 2, the mixing section 71 includes a mixing chamber 72 in which is optionally disposed a displacement rod 73 to define an annular bore 74. As shown in FIG. The smaller of the two streams to be combined (usually the fuel stream) is introduced at inlet 75 and the larger stream (usually the air stream) is introduced through inlet 76 . The eyepieces 77 and 78 are located at the two ends of the displacement rod 73. The eyepiece 78 is preferably a wide-angle lens, which can observe the entire interior of the ignition section 51 and the combustion chamber 52. Even The most ideal implementation is to use the telescope section 79 located in the displacement rod 73 to focus on a specific part of the burner 3, even the interior of the furnace.

In operating this burner, natural gas has been used as fuel, introduced through inlet 75, while air is introduced through inlet 76. Mixing section 71 is a suction air-gas mixer (No. 3065-6) manufactured by North American Manufacturing Co. (Cleveland, Ohio), without displacement rods. The dimensions of the burner can be found under the heading "Dimensions 30.65, 1- 87" in the brochure published by the company, 1-2 pages. With a pressure drop of 51 cm of water column (WC) developed through orifice 74, the above suction unit provided 1.1 x ¹⁰⁶ BTU (British Thermal Units) per hour of natural gas. The annular area of the above holes was 8.3 cm ² . The pressure of natural gas used is 0.102MPa, and the pressure of air is 0.106MPa.

When the combustion-air mixture is measured at openings 69 and 70, a homogeneous mixture will indicate that the flame in combustion chamber 52 is also homogeneous, allowing melting to proceed without introducing undesired amounts of oxygen into the material being melted. It has been affirmed when this burner is used in industrial blast furnaces to smelt copper cathodes. Typical oxygen contents in the copper cathode and finished product are 0.01% and 0.02% by weight, respectively.

It should be understood that many changes and modifications can be made to the few features which have been described without departing from the spirit and scope of the invention. Therefore, the above description is only for explaining the present invention rather than limiting it.

Claims (5)

1, a kind of being installed in is used for the burner of melting copper or analogous material in the blast furnace, and this burner comprises:

One propellant combination stream and oxygen-containing gas stream to be forming the mixing section (50) of homogeneous substance stream, this mixing section (50) have a fuel inlet (36) and an oxygen-containing gas enter the mouth (29) and one be in the mixing section (68) in above-mentioned inlet downstream;

The one flame stabilization section (51) that is connected with above-mentioned mixing section, this flame stabilization section comprise that also being used for lighting above-mentioned homogeneous substance flows to produce a priming bar (58) and a sparking plug (59) of reduction flame; And

One is in the combustion chamber (52) in flame stabilization section (51) downstream, and this combustion chamber (52) are suitable for stretching in the blast furnace;

Be characterised in that above-mentioned gas and fuel inlet are connected with inhaling type gas mixer (71) in the above-mentioned mixing section (50).

2,, be characterised in that also to comprise an eyepiece (77,78) that this eyepiece (77,78) can extend through mixing section (72) vertically, so that observe from this mixing section downstream according to the burner of claim 1.

3, according to the burner of claim 2, be characterised in that eyepiece (77,78) gets telescopical form, it can be adjusted to the part of the required observation of observing burner.

4, according to the burner of claim 2, be characterised in that eyepiece is closed in the bar (73) of one of burner on being arranged in axially, this bar defines the part of inhaling type coupling mechanism in the combustion chamber.

5, a kind of in blast furnace melting copper to produce the method for steel that oxygen level is less than 0.05% fusing of weight, be included in the blast furnace and burn, to produce reduction flame, thus, oxygen containing gas in shortage is conducted to burner, so that perfect combustion is conducted to the fuel of burner, this fuel is low-pressure gas formula liquid fuel, is characterised in that burning is what to carry out in the burner that above-mentioned any one claim limited.

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