JPS61295334A - Smelting furnace - Google Patents

Abstract

PURPOSE:To obtain compact furnace having high productivity and safety, by equalizing bath depth just under a lance almost to permeating depth of blown smelting material, in furnace in which smelting material is blasted through lance provided at furnace ceiling. CONSTITUTION:Since a hearth of smelting furnace in continuous smelting, etc. of sulfide metal ore, is formed to inverse arch state concaving most at the center generally, the bath depths of a melt 3 from a bath level 3a to the hearth 5 are different in places. Here, the bath depth D just under the lance 1 for blasting smelting material such as refined ore, flux, solid fuel and pressed gas such as air, inserted vertically toward the melt 3 from a furnace ceiling 2 is equalized almost to permeating depth of smelting material blasted from the lance 1. The permeating depth means advancing distance of blasted smelting material particles in the melt 3, i.e. the depth permeated toward the hearth 5 from the level 3a. In this way, the erroding action of blasted smelting material received by hearth is relaxed, further the bath depth becomes to necessary and sufficient depth and the aimed furnace is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to the structure of an n-drilling furnace, and more specifically, to the depth of the bath to the hearth.

[Prior art and its problems] Generally, continuous production of sulfide metal ore is carried out. In No. 11, etc., powdered or granular smelting material, seeding agent, solid fuel, etc., are blown into the melt in the furnace together with pressurized gas such as oxygen-enriched air, and the metallurgical reaction proceeds to smelt it. A method is adopted.

In the smelting furnace used for this purpose, as shown in Figures 1 and 2, a runt for injecting smelting raw materials (hereinafter referred to as raw materials) is usually inserted from the furnace ceiling 2 into the melt inside the furnace. It is inserted vertically towards 8. Then, the raw material that is completely blown into the runt is approximately /IjO from the nozzle 1a.
It is released at a speed of m/s or more, collides with the surface 8a of the solution 8 to generate a splash 4t, and then enters the solution 8.

By the way, in this type of smelting furnace, generally speaking, the less the amount of melt 8 that remains in the furnace, the higher the durability of the furnace.
The amount of intermediate product retained can be reduced, and the more compact the furnace, the less equipment investment can be made. Conventional a-melting furnaces are designed so that the bath depth d at the center of the furnace is approximately 1090 mm.

However, in such a smelting furnace with a bath depth of d,
The bricks forming the hearth 5 were severely eroded by the smelting raw materials that were blown into the melt 8 from the runst, and the bricks forming the hearth 5 were carved in an inverted arch shape, and the selvage of the hearth bricks loosened and the bricks fell off. If the bricks are not able to withstand each other's compressive stress, the bricks may be damaged, increasing the risk of the melt 8 flowing out of the furnace.

``Object of the Invention'' The present invention was made in view of the above circumstances, and an object of the present invention is to provide a smelting furnace with high principal property, compactness, and high safety.

"Ninth Means to Solve the Problem" As a result of extensive research, the present inventors determined that by setting the bath depth directly below the lance approximately equal to the penetration depth of the smelting raw material blown from the lance. We have found that the above problems can be solved.

"Example" Hereinafter, the present invention will be described in detail with reference to Examples.

The hearth of a smelting furnace is generally formed in an inverted arch shape with the center of the furnace concave most, so the depth of the bath from the hot water surface 8a to the hearth 5 varies depending on the location. In the smelting furnace of the present invention, the bath depth D directly below the lance 8 is approximately equal to the penetration depth of the smelting raw material injected from the lance 8.

The penetration depth here is defined as the distance that the injected raw material particles travel through the solution 8, that is, the depth of penetration from the melt surface 3a of the solution 8 toward the hearth 5.

The penetration depth of the raw material particles varies depending on various factors. The main factors include the following.

a) The penetration depth increases as the velocity of the raw material particles increases.

b) As the amount of raw material particles supplied per unit cross-sectional area of the nozzle Ia of the lance l increases, the penetration depth becomes deeper.

C) As the specific gravity and viscosity of #body 8 increase, the penetration depth of raw material particles becomes shallower.

d) As the height from the hot water level 8a to the lance increases, the penetration depth of raw material particles becomes shallower.

Based on these findings, the present inventors have discovered that the relationship between the penetration of raw material particles and each factor can be expressed by the following equation.

Hp −y lJ6 dp 1j66 , u, (L
lll, 7” L-uos.

, Ps 112 ,, -024 , Np ,
u cU 512-like TI ・(d6+2Ho−tanθ) −(1) where, Ho/d・o<3. For g, Np-WS/(π/ b *dp ”m Ps-3o
)...(If He/di≧3g, then Np-(Ws/(g/6edp”sps*S!0)
))
,))”+lψ613 Summer Og(H・d/dj)−a
ogψ3 / lo, g (u a / 100) + Q2
3;3 Jog(Ws/S)”-(<4)
(Explanation of symbols) Hp: Penetration depth of raw material particles cs) pL: Density of solution (g/d) Gas velocity at the center of uC nitrogen jet (ell/S) d
o: Internal diameter of lance (am) dp: Diameter of raw material particles (1) So: Cross-sectional area of lance (d) Amount of ore fed per W3 lance (g/S) θ: Spread angle of gas or raw material particles H1・: Lance height from the hot water surface) pL: Viscosity of the solution (, g/cs"s>In the above formula, the density of the solution ('L), the height of the Z-stain H・0), etc. are #! Ren It will be determined automatically by considering the metal to be used and the furnace I & suitable operating conditions.In addition, the number of lances used will be changed to accommodate the amount of ore that changes depending on the amount of raw material.
The true ore supply amount (W s ) is approximately constant.

Therefore, the penetration depth (Hp) of the raw material particles is determined mainly by the lance diameter (do2) and the lance cross-sectional area (so). Here, from the formula,
The thicker the lance l, the deeper the penetration depth (Hp) of the raw material particles becomes.In practice, if the lance l is made thicker directly below the lance l, the density of the raw material particles at the nozzle part (ρS) and the velocity of the raw material particles K
(us, ) and the gas velocity K (uc
) etc. become smaller, so the penetration depth becomes smaller.
On the contrary, it tends to become shallower. Usually, the lance of the smelting furnace is
Since it is said to be more than 3 inches, calculating from this,
The appropriate bath depth D directly below the lance l of the smelting furnace is generally txt.

It is about 13001 or more, preferably about 73001 or more. Even if the bath depth L exceeds /30θ, no improvement in the effect of preventing corrosion of the hearth bricks can be expected, and the amount of melt remaining in the furnace only increases, which is uneconomical.

"Function" In the smelting furnace of the present invention, the bath depth D directly below the lance is set to be approximately equal to the penetration depth of the raw material blown from the lance 1, so the energy of the raw material blown into the hearth collides with the hearth. Significant relief. Therefore, in this smelting furnace, the hearth is less damaged by the erosive action of the injected raw material, and the progress of the erosion is slow.

[Test - A smelting furnace with a bath depth L of /300 mb was designed, constructed, and tested for two years. The tested furnace had a maximum throughput of nLtffton/day and an internal diameter of t/qm.

Internal volume rem, lance diameter d6- 0/am, lance cross-sectional area S1) aoos-oψd, lance height Hα-! r
It's from Ocs. Additionally, the operating conditions of the furnace during the test period were approximately as follows.

Solution density rL-Hirokiyo θ g/- Raw material particle density? s-s, tp~lA2g/d Raw material particle speed ug-200N2tOm/s Gas velocity at the center of the jet ucm20θ~2jOm/s Raw material particle diameter dp-Kota~3j μ Ore feed amount Wj-/φ~/'7 T' /h・Lance spread angle θ-IAφ~448: Viscosity of liquid solution 'L-Q/yO, // g /aaas2
After one year of test operation, the furnace was shut down and the hearth 5 was inspected, and it was found that holes as large as 90 to 3R were formed directly under the lance due to erosion, but in this test furnace, xo-
Only a hole with a depth of 4 cm was formed.

"Effects of the Invention" As explained in detail above, in the smelting furnace of the present invention, the depth of the bath directly below the lance is approximately equal to the depth of penetration of the smelting raw material to be blown, so that the smelting furnace cannot be blown. The raw material alleviates the erosive effects on the hearth. Therefore, the hearth furnace of the present invention has excellent safety without the risk of melt spillage caused by breakage of the hearth bricks or the like.

In addition, since the furnace of the present invention has a bath depth that is necessary and sufficient, the raw violet properties of the furnace will not be deteriorated unnecessarily, and the scale of the furnace will not become unnecessarily large. It is a smelting furnace with an excellent balance of safety, principal property, and model 1.

[Brief explanation of the drawing]

Figures @f and 2 are for detailed explanation of the present invention, with Figure 1 being a longitudinal sectional view of the furnace, and Figure 2 being a top view of the furnace. l...Lance, 2...Furnace ceiling, 8...
...Solution, 8a...Mountain surface, 5...
Hearth, D... Bath depth.

Claims (1)

[Scope of Claims] A smelting furnace in which a lance for blowing smelting raw materials such as concentrate, solvent, solid fuel, and pressurized gas such as air is provided on the ceiling wall of the furnace body where the melt remains, A smelting furnace characterized in that the bath depth from the surface of the melt to the hearth of the furnace body is set to be approximately equal to the penetration depth of smelting raw materials injected from the lance immediately below the lance.