JPS63118026A - Operating method for zinc blast furnace - Google Patents

Abstract

PURPOSE:To reduce coke cost by blowing, as carbonaceous reducing material, coke fines of a specific grain size from a tuyere of a blast furnace. CONSTITUTION:A zinc blast furnace is operated by charging lumpy coke as carbonaceous material and sintered lumps or briquettes as zinc material from the top of a zinc blast furnace and also by introducing air or oxygen-enriched air from a furnace-bottom tuyere. At this time, coke fines of <=1mm average grain size are blown as carbonaceous reducing material together with the above air or oxygen-enriched air to be blown from the above tuyere. The above coke fines mean undersizes or crushed matter of lumpy coke, coke dust generated from a coke oven, crushed matter of oil coke, etc., in which volatile matter and moisture contents are regulated to <=20wt% and <=5wt%, respectively. In this way, inexpensive coke fines to be blown from the tuyere can be substituted for a part of expensive lumpy coke.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an improvement in the method of operating a zinc sinter furnace, and more particularly, to an improvement in the method of operating a zinc sinter furnace, and more particularly, to a method for improving the method of operating a zinc sinter furnace, and more particularly, to improve the method of operating a zinc sinter furnace, and more particularly, to improve the method of operating a zinc sinter furnace. This invention relates to a method of operating zinc 1 while reducing the cost per unit as much as possible.

[Conventional technology]

As is well known, in zinc smelting using a molten ore furnace, lump coke, which is a carbonaceous reducing agent, and sintered lumps or briquettes, which are raw materials for zinc, are charged from the top of the furnace, and air or oxygen is introduced from the tuyere at the bottom of the furnace. Enriched air is introduced and zinc vapor? The gases contained are removed from an outlet near the top of the furnace, and zinc is condensed from this vapor by a condenser sprinkled with a spray of molten lead drops. The molten heat is discharged from the bottom of the furnace along with the Pb prions.

The cost of coke as a carbonaceous reducing agent accounts for an extremely large proportion of the smelting cost in zinc smelting using such a smelting furnace, and therefore the development of a method to reduce the coke cost per gold filt recovered is awaited. ing.

[Problem that the invention seeks to solve]

An object of the present invention is to obtain a method for operating a zinc smelting furnace that reduces coke costs.

[Means for solving problems]

To achieve this objective, the present inventor has developed the present invention as a carbonaceous transition agent in the operation of a zinc smelting furnace with an average particle size of 1 m.
The furnace is constructed so that powdered coke of 3 m or less is blown into the furnace through the tuyeres.

[Effect]

In the present invention, lump coke, which is a carbonaceous reducing agent, and sintered lumps or briquettes, which are raw materials for zinc, are charged from the top of the zinc melting furnace, and air or oxygen-enriched air is introduced from the tuyeres at the bottom of the furnace. When operating a zinc smelt furnace, powdered coke with an average particle size of 1 mm or less is injected as a carbonaceous reducing agent together with air or oxygen-enriched air introduced through the tuyeres.

This coke powder refers to the unsieved or crushed coke of lump coke, coke dust generated from coke ovens, crushed oil coke, etc., and has a volatile content of 20% or less and a moisture content of 5% or less. .

If the volatile content exceeds 20% by weight or the water content exceeds 5% by weight, the zinc vapor taken out from the zinc smelting furnace will be re-oxidized by water vapor, and zinc oxide dross will increase in the duster, reducing the zinc recovery rate. It becomes easier to decrease. If the average particle size of the powdered coke exceeds 1 mm, the coke cannot sufficiently contribute to the reduction reaction in the reaction zone at the tuyere tip, and the temperature at the tuyere tip decreases due to the increased amount of blown air.

In this way, by injecting cheap powdered coke through the tuyere, the amount of expensive lump coke charged from the top of the furnace can be reduced. (Lump and powder) costs can be significantly reduced relative to the same conventional coke (Lump) costs.

The degree of this reduction is large even if the amount of powdered coke used is small. Also, if the amount used is increased, the cost reduction will generally increase, but if it is used too much, (1)
The proportion of sintered lumps or briquettes in the charge from the top of the furnace increases, making it easier for them to become semi-molten in the furnace, which increases the ventilation resistance in the furnace, and (2) ) The combustion rate of the injected powdered coke in the reaction zone decreases, which tends to interfere with the stable operation of the blast furnace, so naturally the amount used is approximately 40% of the total coke.
%.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Example Hearth area 11.8 m with 16 tuyeres of 128 diameters
, size 25 from the top of the zinc melting furnace with a height of 10.8 m.
~100 mm of lump coke and sintered mass were charged in a charging packet, and air was heated to 950C. Coke dust and pulverized coal generated from a coke oven having the composition and particle size shown in Table 1 are introduced from the tuyere at a rate of 0 to 0.12 t/hour from a 25 mm diameter nozzle dedicated to injecting carbonaceous reducing agent. A zinc molten ore furnace was operated by blowing. On this occasion,
The injection of coke dust was carried out with 12 Nm/h of air for flow, and the injection of pulverized coal was carried out with 12 Nm/h of nitrogen for flow, rather than air with a high risk of explosion. In addition, each operation period is fixed at two weeks, and the amount of metal zinc produced during that period is 200 to 230 tons.
/ day.

Table 1 The conditions of these operations and the results obtained are shown in Table 2.

Table 2 *1 Replacement rate (%) = -x 1o.

Yu *3 *5 *2 Exchange rate ((5) = -X 100 *3 a: Amount of lump coke per 1 recovered metallic zinc during operation with only lump coke without blowing x 4 b : Amount of injected coke dust or pulverized coal per 1 unit of recovered metal zinc *5 c : Amount of lump coke per 1 unit of recovered metal zinc when operating with injection [Effects of the invention] From the above As is clear, by replacing a portion of the expensive lump coke with inexpensive powder coke injected through the tuyere and operating the zinc smelting furnace, the cost of zinc smelting becomes extremely large. reduce the cost of carbonaceous reducing agent,
Zinc recovery rate B in the condenser can be significantly reduced while maintaining the same as before.

Claims (1)

[Claims] (1) A method for operating a zinc molten slag furnace, which comprises injecting powdered coke with an average particle size of 1 mm or less as a carbonaceous reducing agent through the tuyere of the furnace.