JPH0733536B2 - Method for adding powdered chromium ore during molten iron blowing - Google Patents
Method for adding powdered chromium ore during molten iron blowingInfo
- Publication number
- JPH0733536B2 JPH0733536B2 JP2214318A JP21431890A JPH0733536B2 JP H0733536 B2 JPH0733536 B2 JP H0733536B2 JP 2214318 A JP2214318 A JP 2214318A JP 21431890 A JP21431890 A JP 21431890A JP H0733536 B2 JPH0733536 B2 JP H0733536B2
- Authority
- JP
- Japan
- Prior art keywords
- ore
- reaction vessel
- lance
- powdery
- blowing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 title claims description 51
- 239000011651 chromium Substances 0.000 title claims description 46
- 229910052804 chromium Inorganic materials 0.000 title claims description 40
- 238000007664 blowing Methods 0.000 title claims description 33
- 238000000034 method Methods 0.000 title claims description 22
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 title claims description 16
- 229910052742 iron Inorganic materials 0.000 title claims description 8
- 239000007789 gas Substances 0.000 claims description 28
- 239000002893 slag Substances 0.000 claims description 24
- 238000006243 chemical reaction Methods 0.000 claims description 21
- 229910052751 metal Inorganic materials 0.000 claims description 15
- 239000002184 metal Substances 0.000 claims description 15
- 239000003575 carbonaceous material Substances 0.000 claims description 9
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 8
- 239000001301 oxygen Substances 0.000 claims description 8
- 229910052760 oxygen Inorganic materials 0.000 claims description 8
- 239000002245 particle Substances 0.000 claims description 8
- 229910052756 noble gas Inorganic materials 0.000 claims 2
- 230000003647 oxidation Effects 0.000 claims 2
- 238000007254 oxidation reaction Methods 0.000 claims 2
- 238000006213 oxygenation reaction Methods 0.000 claims 2
- 230000003068 static effect Effects 0.000 claims 1
- 229910000831 Steel Inorganic materials 0.000 description 18
- 239000010959 steel Substances 0.000 description 18
- 238000010586 diagram Methods 0.000 description 4
- 238000002474 experimental method Methods 0.000 description 4
- 230000001590 oxidative effect Effects 0.000 description 4
- 230000014509 gene expression Effects 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 2
- 238000003723 Smelting Methods 0.000 description 2
- 230000001174 ascending effect Effects 0.000 description 2
- 239000000571 coke Substances 0.000 description 2
- 238000005453 pelletization Methods 0.000 description 2
- LFYJSSARVMHQJB-QIXNEVBVSA-N bakuchiol Chemical compound CC(C)=CCC[C@@](C)(C=C)\C=C\C1=CC=C(O)C=C1 LFYJSSARVMHQJB-QIXNEVBVSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 239000000112 cooling gas Substances 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000001294 propane Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
Landscapes
- Carbon Steel Or Casting Steel Manufacturing (AREA)
Description
【発明の詳細な説明】 ＜産業上の利用分野＞ 本発明は、上吹きランスから酸素を吹込み溶鉄を吹錬す
る転炉中に粉状クロム鉱石を添加する技術に関するもの
である。TECHNICAL FIELD The present invention relates to a technique for adding powdery chromium ore into a converter for blowing oxygen from a top blowing lance to blow molten iron.
＜従来の技術＞ 本発明は、事前処理しない鉱石と炭材を原料として溶融
還元法によって金属溶湯を得る方法に関するが、事前処
理を行わない鉱石は粉状または粒状（以下粉粒状と称
す）のものが多く、それらを歩留りよく反応容器中に添
加するためには飛散防止を図らなければならないという
問題があった。特に、転炉型の容器は、炉口の断面積が
炉腹に比べて小さく、ガスの上昇速度が大きいので、炉
口を経由して粉粒状の鉱石を落下させても、比較的細か
い粉度の鉱石はガス上昇流によって搬送されて容器内に
到達しない場合が多々あった。すなわち、上記の方法は
添加留りが低く、経済的な方法といえなかった。<Prior Art> The present invention relates to a method for obtaining a molten metal by a smelting reduction method using ores and carbonaceous materials that are not pretreated as raw materials. However, ores that are not pretreated are powdery or granular (hereinafter referred to as powdery or granular). There are many substances, and there is a problem that scattering must be prevented in order to add them to the reaction vessel with good yield. In particular, a converter-type container has a smaller cross-sectional area at the furnace opening than the bellows and a higher gas rising speed, so even if a granular ore is dropped through the furnace opening, a relatively fine powder is obtained. In many cases, the ore of the same degree was transported by the upward flow of gas and did not reach the container. That is, the above method has a low addition residue and cannot be said to be an economical method.
また、粉粒状の鉱石の歩留りを向上させるため、特開昭
60−208409号公報に開示されたように上吹きランスから
炭材と酸化性ガスを、不活性ガスに搬送された鉱石とと
もに噴射する方法がある。この方法は添加歩留りは高い
ものの、ランス内の鉱石の搬送速度が大きいのでランス
内壁面の摩耗が多いという問題があった。Further, in order to improve the yield of powdery ore,
As disclosed in Japanese Patent Laid-Open No. 60-208409, there is a method of injecting a carbonaceous material and an oxidizing gas from an upper blowing lance together with an ore carried in an inert gas. Although this method has a high addition yield, it has a problem that the inner wall surface of the lance is often worn due to the high transfer speed of the ore in the lance.
また、特開昭59−126707号公報に開示されたように、粉
状のクロム鉱石をペレット化して炉内に添加し歩留りを
上げる方法もあるが、ペレット化するための処理費用が
嵩むので経済的な方法とは言えなかった。Further, as disclosed in JP-A-59-126707, there is also a method of pelletizing powdery chromium ore and adding it to the furnace to increase the yield, but the processing cost for pelletizing increases, so it is economical. It wasn't the right way.
＜発明が解決しようとする課題＞ 本発明は、かかる現状に鑑み、粉状クロム鉱石の添加歩
留りを高く維持したまま、特殊なランスを使わずに経済
的に金属溶湯を得る技術を提供するためになされたもの
である。<Problems to be Solved by the Invention> In view of the present situation, the present invention provides a technique for economically obtaining a molten metal without using a special lance while maintaining a high addition yield of powdered chromium ore. It was done by.
＜課題を解決するための手段＞ 本発明は、粉状クロム鉱石と炭材を上吹きを主体とす
る上底吹き可能な反応容器内に供給しつつ、溶鉄浴面上
の軸芯に設けられた上吹きランスから酸素または酸化性
ガスを2.6Nm3/min/t以上8.6Nm3/min/t以下噴射して金属
溶湯を得る方法であって、下記の（１）、（２）式で求
められる水平距離ｒと高さＺとで区画される領域内に、
1mm以下の粒径の粉状クロム鉱石を3.0m/s以下の速度で
添加することを特徴とする溶鉄吹錬時の粉状クロム鉱石
添加方法である。<Means for Solving the Problems> The present invention is provided on a shaft core on a molten iron bath surface while supplying powdery chrome ore and carbonaceous material into a reaction vessel capable of upper-bottom blowing mainly of upper-blowing. A method for obtaining a molten metal by injecting oxygen or an oxidizing gas from 2.6 Nm 3 / min / t or more to 8.6 Nm 3 / min / t or less from a top-blown lance according to the following formulas (1) and (2). Within the area defined by the required horizontal distance r and height Z,
A method for adding powdery chromium ore at the time of molten iron blowing, which comprises adding powdery chromium ore having a particle size of 1 mm or less at a rate of 3.0 m / s or less.
記 ｒ≦0.8r0 ………（１） 0.2L≦Ｚ≦1.1L ………（２） ここで、 r:反応容器のランス軸芯から領域側端までの水平距離
（ｍ）、 r0:反応容器のランス軸芯から反応容器内壁までの水平
距離（ｍ）、 Z:静止状態のスラグ表面を起点とした高さ（ｍ）、 L:静止状態のスラグ表面と上吹きランス先端部までの垂
直距離（ｍ）。Note r ≦ 0.8r 0 (1) 0.2L ≦ Z ≦ 1.1L (2) where r: horizontal distance (m) from the lance axis of the reaction vessel to the end of the area, r 0 : Horizontal distance from the lance axis of the reaction vessel to the inner wall of the reaction vessel (m), Z: Height starting from the stationary slag surface (m), L: From the stationary slag surface to the tip of the top blowing lance Vertical distance of (m).
また、粉状クロム鉱石と炭材を上吹きを主体とする上
底吹き可能な反応容器内に供給しつつ、溶鉄浴面上の軸
芯に設けられた上吹きランスから酸素または酸化性ガス
を2.6Nm3/min/t以上8.6Nm3/min/t以下噴射して金属溶湯
を得る方法であって、1mm以下の粒径の粉状クロム鉱石
の添加位置が（１）、（４）式で求められる領域内であ
り、かつその位置での粉状クロム鉱石の下向き流速ＶＤ
が（３）式を満たすようにして添加することを特徴とす
る粉状クロム鉱石添加方法である。Further, while supplying the powdery chrome ore and carbonaceous material into the upper bottom-blown reaction vessel capable of upper-bottom blowing, oxygen or oxidizing gas is supplied from the upper-blowing lance provided on the shaft core on the molten iron bath surface. 2.6Nm 3 / min / t or more and 8.6Nm 3 / min / t or less is a method of obtaining a molten metal by adding powdered chromium ore with a particle size of 1 mm or less to the positions (1) and (4). The downward flow velocity V D of the pulverized chrome ore in the region determined by
Is added so as to satisfy the formula (3).
記 ｒ≦0.8r0 ………（１） 40≧ＶＤ−Ｖｅ≧５ ………（３） 1.1L＜Ｚ≦1.5L ………（４） ここで、 r:反応容器のランス軸芯から領域側端までの水平距離
（ｍ）、 r0:反応容器のランス軸芯から反応容器内壁までの水平
距離（ｍ）、 ＶＤ：粉状クロム鉱石の下向きの流速（m/s）、 Ｖｅ：粉状クロム鉱石添加位置での炉内排ガスの上向き
の流速（m/s）、 Z:静止状態のスラグ面を起点とした高さ（ｍ）、 L:静止状態のスラグ表面と上吹きランス先端部までの垂
直距離（ｍ）。Note r ≦ 0.8r 0 (1) 40 ≧ V D −V e ≧ 5 (3) 1.1L <Z ≦ 1.5L… (4) where r: Lance axis of reaction vessel Horizontal distance from core to edge of region (m), r 0 : Horizontal distance from lance shaft core of reaction vessel to inner wall of reaction vessel (m), V D : Downward flow velocity of powdered chromium ore (m / s) , V e : Upward flow velocity (m / s) of the furnace exhaust gas at the position where the powdery chromium ore is added, Z: Height (m) from the stationary slag surface as the starting point, L: With the stationary slag surface Vertical distance (m) to the tip of the upper blowing lance.
＜発明をなすに至った経過及び作用＞ 従来、転炉内のガス流れは、第５図に模式的に示されて
いるように考えられていた。すなわち、上吹きランス５
から噴射されたO2ガスは、周囲のガスと反応しつつスラ
グ４に衝突し、反応した後炉壁に沿って上昇流6aとなっ
て上昇し、上方では上吹きランス中心軸にまで達する。
しかし、本発明者らの観察によると第６図に示すように
ガス流れは上昇流6aの外に、上吹きランス先端部のレベ
ルに下降流6bの存在が認められた。また、上昇流6aが存
在する範囲も従来考えられていた範囲よりも狭く、壁近
傍に限られていることがわかった。<Processes and Actions That Achieve the Invention> Conventionally, the gas flow in the converter has been considered as schematically shown in FIG. That is, the top blowing lance 5
The O 2 gas injected from the above collides with the slag 4 while reacting with the surrounding gas, and after reacting, rises as an ascending flow 6a along the furnace wall, and reaches the central axis of the upper blowing lance above.
However, according to the observations of the present inventors, as shown in FIG. 6, the gas flow was found to have a downward flow 6b at the level of the tip of the upper blowing lance in addition to the upward flow 6a. It was also found that the range in which the ascending flow 6a exists was narrower than the range conventionally considered, and was limited to the vicinity of the wall.
ここで鉱石の添加位置の起点をガス流れの下降流の位置
またはその近傍とすれば、鉱石は下降流に搬送され、か
つ鉱石自身も下向きの運動エネルギを備えているので、
スラグ層または溶鋼層近傍に形成されるガス流の反転流
6cを横切ってスラグ層または溶鋼層に到達し、鉱石はス
ラグ層または溶鋼層に確実に捕捉される。If the starting point of the ore addition position is at or near the position of the downward flow of the gas flow, the ore is transported to the downward flow, and the ore itself also has downward kinetic energy,
Reverse flow of gas flow formed near slag layer or molten steel layer
The slag layer or molten steel layer is reached across 6c, and the ore is reliably trapped in the slag layer or molten steel layer.
さらに、添加歩留りを向上させるために、粉状クロム鉱
石の添加位置の起点を変え、上吹き酸素流量、上吹きラ
ンス孔数、上吹きランス高さ等を数多く変化させた実験
を行い、上吹きランスから酸素または酸化性ガスを2.6N
m3/min/t以上8.6Nm3/min/t以下で噴射した場合、下記式
で求められる反応容器のランス軸芯からの水平距離ｒ、
静止状態のスラグ表面を起点とした高さＺで区画される
領域（第３図参照）内に1mm以下の粒径の粉状クロム鉱
石を添加すれば添加歩留りがよいことを出した。In addition, in order to improve the yield of addition, the starting point of the addition position of the powdered chromium ore was changed, and various experiments were performed in which the number of top-blown oxygen flow, the number of top-blown lance holes, the top-blown lance height, etc. were varied. 2.6N oxygen or oxidizing gas from lance
When sprayed at m 3 / min / t or more and 8.6 Nm 3 / min / t or less, the horizontal distance r from the lance axis of the reaction vessel calculated by the following formula,
It was shown that the addition yield was good if a powdery chrome ore with a grain size of 1 mm or less was added to the region (see FIG. 3) defined by the height Z from the stationary slag surface as the starting point.
記 ｒ≦0.8r0 ………（１） 0.2L≦Ｚ≦1.1L ………（２） ここで、 r:反応容器のランス軸芯から領域側端までの水平距離
（ｍ）、 r0:反応容器のランス軸芯から反応容器内壁までの水平
距離（ｍ）、 Z:静止状態のスラグ表面を起点とした高さ（ｍ）、 L:静止状態のスラグ表面と上吹きランス先端部までの垂
直距離（ｍ）。Note r ≦ 0.8r 0 (1) 0.2L ≦ Z ≦ 1.1L (2) where r: horizontal distance (m) from the lance axis of the reaction vessel to the end of the area, r 0 : Horizontal distance from the lance axis of the reaction vessel to the inner wall of the reaction vessel (m), Z: Height starting from the stationary slag surface (m), L: From the stationary slag surface to the tip of the top blowing lance Vertical distance of (m).
第３図に（１）式、（２）式のｒ、Ｚで区画された領域
を示す。図のようにランスとスラグ層に囲まれた中心部
領域を粉状クロム鉱石の添加位置とすればよいことがわ
かった。かかる領域に1mm以下の粒径の粉状クロム鉱石
を3.0m/s以下の速度で添加すれば粉状クロム鉱石の流速
を極端に低くした場合でも粉状クロム鉱石の添加歩留り
を高くできることがわかった。この理由は既に述べたよ
うに転炉内に発生する下降流6bに添加した粉状クロム鉱
石が搬送されるためである。粉状クロム鉱石を運搬・添
加する手段として、例えば第１図に示すような方法があ
るが、他にどの手段でも構わない。FIG. 3 shows the regions partitioned by r and Z in the equations (1) and (2). As shown in the figure, it was found that the central region surrounded by the lance and the slag layer should be the addition position of the powdery chromium ore. It was found that by adding powdered chromium ore with a particle size of 1 mm or less to such a region at a speed of 3.0 m / s or less, the yield of powdered chromium ore can be increased even if the flow rate of powdered chromium ore is extremely low. It was The reason for this is that the powdered chromium ore added to the downflow 6b generated in the converter is transported as described above. As a means for carrying and adding the powdery chromium ore, for example, there is a method as shown in FIG. 1, but any other means may be used.
第１図の７は、出鋼口10に耐火物製カバーを設けた鋼製
パイプであり、溶融還元中に炉内に挿入し、当該パイプ
の先端すなわち粉状クロム鉱石添加の起点を当該
（１），（２）式のｒ、Ｚで区画された領域に位置せし
めた場合である。粉状クロム鉱石の添加のためのパイプ
は７以外にも第１図の鋼製パイプ８や９のように炉口11
や炉肩12を通して挿入してもよい。Reference numeral 7 in FIG. 1 is a steel pipe having a refractory cover provided on the tap hole 10, which is inserted into the furnace during the smelting reduction, and the tip of the pipe, that is, the starting point of the addition of the powdery chromium ore is concerned ( This is a case where they are located in a region partitioned by r and Z in the expressions 1) and (2). In addition to the pipe 7 for addition of powdered chromium ore, the steel pipes 8 and 9 in FIG.
It may also be inserted through the furnace shoulder 12.
以上のように各種実験から、粉状クロム鉱石の搬送用パ
イプの磨耗を少なくし、かつ鉱石の添加歩留りがよい粉
状クロム鉱石の添加位置が明らかとなったわけである
が、第１図に示す方法では操業方法によっては不都合な
点が生じる場合があった。As described above, various experiments have revealed the position of addition of the powdery chromium ore, which reduces wear of the powdery chromium ore transport pipe and has a good addition rate of the ore, as shown in FIG. In some cases, disadvantages may occur depending on the operation method.
すなわち、第５図あるいは第６図に示される底吹き羽口
２から吹込まれるガスが、酸素を主体とするガスでかつ
流量が0.3Nm3/min/t以上の場合には、スラグや溶鋼が添
加用のパイプに飛散付着してパイプが溶損される場合が
あった。That is, when the gas blown from the bottom blowing tuyere 2 shown in FIG. 5 or 6 is a gas mainly containing oxygen and the flow rate is 0.3 Nm 3 / min / t or more, slag and molten steel There was a case where the powder was scattered and adhered to the pipe for addition and the pipe was melted and damaged.
また、粉状クロム鉱石の添加速度を数m/s以下まで低下
させた場合には、パイプ先端がスラグの付着によって閉
塞することがあった。これは底吹きガス流量が大きい場
合は溶鋼の撹拌力が大きくなるので還元には有利となる
が、スピッティングによる溶鋼の飛散やスラグの飛散が
大となる。その結果、粉状クロム鉱石を添加する位置と
して（１），（２）式を満たす位置では、鉱石供給用の
パイプが底吹きガス流量が大きい場合には溶損する恐れ
が生ずる。In addition, when the addition rate of powdered chrome ore was reduced to several m / s or less, the tip of the pipe was sometimes blocked due to the adhesion of slag. This is advantageous for reduction because the stirring force of the molten steel becomes large when the flow rate of the bottom blowing gas is large, but the scattering of molten steel and the scattering of slag due to spitting become large. As a result, at the position where the pulverized chromium ore is added and the formulas (1) and (2) are satisfied, the ore supply pipe may be melted when the bottom blown gas flow rate is large.
そこでさらに広範囲に条件を変更させて鉱石の添加歩留
りを調べたところ、第４図に示すように鉱石を添加する
位置での炉内排ガスの上向きの流速をＶｅ（m/s）、鉱
石の下向きの流速をＶＤ（m/s）とし、次式を導いた。Therefore, when the addition yield of ore was investigated by changing the conditions over a wider range, as shown in FIG. 4, the upward flow velocity of the exhaust gas in the furnace at the position where the ore was added was V e (m / s), The following equation was derived with the downward flow velocity being V D (m / s).
40≧ＶＤ−Ｖｅ≧５（m/s） ………（３） この（３）式の関係を満たせば（２）式を満たさない前
記（４）式の領域から添加した場合でも、本発明者らの
行った実験結果を示す第２図から、高添加歩留りが得ら
れることが確認された。40 ≧ V D −V e ≧ 5 (m / s) (3) If the relation of this equation (3) is satisfied, even if it is added from the region of the above equation (4) that does not satisfy equation (2), From FIG. 2 showing the results of experiments conducted by the present inventors, it was confirmed that a high addition yield was obtained.
なお、（１）式、（２）式を満たす領域では既に述べた
ように排ガスの上向きの流速Ｖｅが小さいか、または下
向きになるので鉱石の速度ＶＤを小さくしても（３）式
を満たすことになる。It should be noted that, in the region satisfying the formulas (1) and (2), the upward flow velocity V e of the exhaust gas is small or downward as described above, and therefore the formula (3) is obtained even if the ore velocity V D is reduced. Will be met.
そこで添加用ランスの位置を半径方向・高さ方向をさら
に変化させて検討したところ、（１）式を満たす範囲内
にランス添加用パイプを配置すれば粉状クロム鉱石の添
加速度を比較的低くしても（３）式を満たすのが容易で
あることがわかった。ただし、ランス添加用パイプの高
さを極端に高くして炉口レベルまで高くすると、粉状ク
ロム鉱石の添加速度を大きくする必要があった。静止状
態のスラグ表面を起点とした高さＺをおよそ静止状態の
スラグ表面と上吹きランス先端までの垂直距離Ｌの２倍
以下、望ましくは1.5倍以下にするのが望ましいと考え
られる。Therefore, when the position of the addition lance was examined by changing the radial direction and the height direction further, if the lance addition pipe was placed within the range satisfying the formula (1), the addition rate of the powdered chromium ore was relatively low. However, it has been found that it is easy to satisfy the expression (3). However, if the height of the pipe for lance addition was made extremely high to the level of the furnace mouth, it was necessary to increase the addition rate of the powdery chromium ore. It is considered that the height Z from the stationary slag surface as the starting point is approximately twice or less, preferably 1.5 times or less, the vertical distance L between the stationary slag surface and the tip of the upper blowing lance.
なお、粉状クロム鉱石の粒度は粗ければ上昇流による飛
散がないのは当然である。1mmアンダーの粉状クロム鉱
石で本発明による方法が特に有効である。Naturally, if the particle size of the pulverized chrome ore is coarse, it will not be scattered by the upward flow. The method according to the invention is particularly effective for pulverized chrome ores of 1 mm under.
以下に本発明の実施例を説明する。Examples of the present invention will be described below.
＜実施例＞ （実施例１） 5tの試験転炉を用いた。底吹き羽口は内径3mmφの単管
で、羽口本数は４本であり、底吹きガス流量はスピッテ
ィングを抑えるように0.5〜1.5Nm3/minでArガスを用い
た。上吹きランスは６孔で12mmφ、O2ガス流量は10〜30
Nm3/minとした。また、炭材としてコークスを10〜30kg/
minの割合で炉上から添加した。さらに粉状クロム鉱石
（粒度：＜500μｍ）を10〜30kg/minの割合で投入し
た。粉状クロム鉱石の組成は第１表のとおりである。<Example> (Example 1) A 5 ton test converter was used. The bottom-blowing tuyere was a single tube with an inner diameter of 3 mmφ, the number of tuyere was 4, and the bottom-blowing gas flow rate was 0.5 to 1.5 Nm 3 / min using Ar gas so as to suppress spitting. Top blowing lance has 6 holes and 12mmφ, O 2 gas flow rate is 10-30
It was set to Nm 3 / min. In addition, coke as a carbon material is 10-30 kg /
It was added from above the furnace at a rate of min. Further, powdery chromium ore (particle size: <500 μm) was added at a rate of 10 to 30 kg / min. The composition of the powdery chromium ore is shown in Table 1.
本実施例および比較例ともにC:4.4〜4.5重量％（以下％
と略す）,Si:0.1〜0.2％、Mn:0.4〜0.5％の溶銑を3.5〜
3.7t装入し、溶銑温度を1550〜1600℃に保つようにし、
最終的にC:5.3〜5.5％,Cr:15〜16％のクロム溶銑を得
た。上吹きランスはスラグ表面〜ランス先端間の距離を
0.3〜1.5mの間で変化させた。なお、5t転炉は炉芯を垂
直に通過する軸に対称の容器であり、その寸法は第７図
のとおりでありr0＝0.75mである。C: 4.4 to 4.5% by weight (hereinafter,%
, Si: 0.1-0.2%, Mn: 0.4-0.5% hot metal 3.5-
Charge 3.7t and keep the hot metal temperature at 1550 ~ 1600 ℃,
Finally, chromium hot metal with C: 5.3-5.5% and Cr: 15-16% was obtained. The top blowing lance measures the distance between the slag surface and the tip of the lance.
It was changed between 0.3 and 1.5 m. The 5t converter is a vessel that is symmetrical with respect to the axis passing vertically through the core, and its dimensions are as shown in Fig. 7 and r 0 = 0.75m.
また、実施例および比較例の実施条件及び結果を第２表
に示す。Table 2 shows the working conditions and results of the examples and comparative examples.
第２表から、粉状クロム鉱石の添加位置を本発明に係る
領域内にすれば良好なCrの添加歩留りが得られることが
明らかである。なお、ここでいうCr歩留りとは、全添加
Cr鉱石中のCr重量に対するメタルとスラグへ歩留ったCr
重量の割合である。It is clear from Table 2 that a good Cr addition yield can be obtained if the addition position of the powdery chromium ore is within the region according to the present invention. The Cr yield here is the total addition.
Cr yielded to metal and slag relative to Cr weight in Cr ore
It is a ratio of weight.
（実施例２） 60〜85tの大型転炉による実験も行った。大型転炉では
二重管羽口（内管径17mmφ、羽口６本）を用いて底吹き
ガスとして1.0〜1.3Nm3/min/t溶鋼のO2を吹き込んだ。
外管からは冷却用ガスとしてプロパンを用いて0.04〜0.
06Nm3/min/t溶鋼を吹き込んだ。上吹きランスは30mmφ
の６つのストレート孔を有し、O2ガス流量は2.6〜2.8Nm
3/min/t溶鋼とした。炭材は4.3〜5.8kg/min/t溶鋼のコ
ークスを炉上から添加した。 (Example 2) An experiment using a large converter of 60 to 85 tons was also conducted. In a large-scale converter, double tube tuyere (inner tube diameter 17 mmφ, 6 tuyere) was used to blow 1.0 to 1.3 Nm 3 / min / t molten steel O 2 as bottom blowing gas.
Propane is used as a cooling gas from the outer tube at 0.04 to 0.
06Nm 3 / min / t Molten steel was blown. Top blowing lance is 30mmφ
Has 6 straight holes and the O 2 gas flow rate is 2.6 ~ 2.8Nm
3 / min / t molten steel. As the carbon material, 4.3 to 5.8 kg / min / t molten steel coke was added from above the furnace.
粉状クロム鉱石は4.3〜6.2kg/min/t溶鋼の割合で投入し
た。粉状クロム鉱石の組成、粒径、溶銑の組成は実施例
１とほぼ同じである。Powdered chromium ore was added at a rate of 4.3 to 6.2 kg / min / t molten steel. The composition of the chrome ore powder, the particle size, and the composition of the hot metal are almost the same as in Example 1.
溶銑を45〜60t装入し、溶銑温度を1550〜1600℃まで上
昇させた後クロム鉱石と炭材を添加し最終的に〔％Ｃ〕
＝5.3〜5.5、〔％Cr〕＝13〜15のクロム溶銑を得た。こ
こで第１図に示す鉱石添加用の鋼製パイプ８の高さ・半
径方向の位置を変化させて操業を行った。第３表にその
結果を示す。Charge 45 to 60 tons of hot metal, raise the temperature of hot metal to 1550 to 1600 ° C, then add chromium ore and carbonaceous material and finally [% C]
= 5.3 to 5.5, [% Cr] = 13 to 15 were obtained. Here, the operation was performed by changing the height and radial position of the steel pipe 8 for ore addition shown in FIG. The results are shown in Table 3.
（１）式および（３）式を満たす操業を行えば高い歩留
りで粉状クロム鉱石を添加できることがわかる。一方、
（３）式を満たさない場合では粉状クロム鉱石の飛散が
大きく、結果的にダスト発生量の増加やCr歩留りの低下
を招き経済的な溶製が難しいことがわかる。It is understood that the powdery chromium ore can be added with a high yield if the operation satisfying the expressions (1) and (3) is performed. on the other hand,
It is understood that if the formula (3) is not satisfied, the powdery chromium ore is largely scattered, resulting in an increase in the amount of dust generation and a decrease in the Cr yield, making it difficult to economically melt.
＜発明の効果＞ 本発明によれば、粉状クロム鉱石を事前処理せずに、輸
送パイプの摩耗も少なく、しかも高添加歩留りで溶融還
元することができるので、金属溶湯を安価に歩留りよく
製造することができる。 <Effects of the Invention> According to the present invention, it is possible to produce a molten metal at low cost and with good yield, since the powdery chromium ore can be melted and reduced with a high addition yield without pretreatment of the chromium ore and the wear of the transportation pipe is small. can do.
第１図は、本発明に係る方法の具体的実施（例）を示す
模式図、第２図は、（ＶＤ−Ｖｅ）と添加歩留りの関係
を示す特性図、第３図は、本発明に係る区画された領域
を示す説明図、第４図は、ＶＤ、Ｖｅの説明図、第５図
は、従来考えられていた転炉内のガス流を示す模式図、
第６図は、本発明者らが見出した転炉内のガス流を示す
模式図、第７図は、実施例に用いた転炉の形状、寸法を
示す説明図である。 １……転炉、２……底吹き羽口、 ３……金属溶湯、４……スラグ、 ５……上吹きランス、６……ガス流、 6a……上昇流、6b……下降流、 6c……反転流、７……鋼製パイプ、 ８……鋼製パイプ、９……鋼製パイプ、 10……出鋼口、11……炉口、 12……炉肩。FIG. 1 is a schematic diagram showing a specific implementation (example) of the method according to the present invention, FIG. 2 is a characteristic diagram showing the relationship between (V D −V e ) and the addition yield, and FIG. FIG. 4 is an explanatory view showing a partitioned area according to the invention, FIG. 4 is an explanatory view of V D and V e , and FIG. 5 is a schematic view showing a gas flow in a conventional converter.
FIG. 6 is a schematic diagram showing the gas flow in the converter found by the present inventors, and FIG. 7 is an explanatory diagram showing the shape and dimensions of the converter used in the examples. 1 ... Converter, 2 ... Bottom blowing tuyere, 3 ... Metal melt, 4 ... Slag, 5 ... Top blowing lance, 6 ... Gas flow, 6a ... Upflow, 6b ... Downflow, 6c ... reverse flow, 7 ... steel pipe, 8 ... steel pipe, 9 ... steel pipe, 10 ... steel tap, 11 …… furnace mouth, 12 …… furnace shoulder.
フロントページの続き (72)発明者 桜谷 敏和 千葉県千葉市川崎町１番地 川崎製鉄株式 会社技術研究本部内 (72)発明者 藤井 徹也 千葉県千葉市川崎町１番地 川崎製鉄株式 会社技術研究本部内 (72)発明者 大杉 仁 千葉県千葉市川崎町１番地 川崎製鉄株式 会社千葉製鉄所内 (56)参考文献 特開 昭58−136709（ＪＰ，Ａ) 特開 昭62−211347（ＪＰ，Ａ)Front page continuation (72) Inventor Toshikazu Sakuraya, 1 Kawasaki-cho, Chiba, Chiba Prefecture, Technical Research Headquarters, Kawasaki Steel Co., Ltd. (72) Tetsuya Fujii, 1 Kawasaki-machi, Chiba, Chiba Pref. (72) Inventor Hitoshi Osugi 1 Kawasaki-cho, Chiba-shi, Chiba Inside the Chiba Works, Kawasaki Steel Co., Ltd.
Claims (2)
る上底吹き可能な反応容器内に供給しつつ、溶鉄浴面上
の軸芯に設けられた上吹きランスから酸素または酸化性
ガスを2.6Nm3/min/t以上8.6Nm3/min/t以下噴射して金属
溶湯を得る方法であって、 下記の（１）、（２）式で求められる水平距離ｒと高さ
Ｚとで区画される領域内に、1mm以下の粒径の粉状クロ
ム鉱石を3.0m/s以下の速度で添加することを特徴とする
溶鉄吹錬時の粉状クロム鉱石添加方法。 記 ｒ≦0.8r0 ………（１） 0.2L≦Ｚ≦1.1L ………（２） ここで、 r:反応容器のランス軸芯から領域側端までの水平距離
（ｍ）、 r0:反応容器のランス軸芯から反応容器内壁までの水平
距離（ｍ）、 Z:静止状態のスラグ表面を起点とした高さ（ｍ）、 L:静止状態のスラグ表面と上吹きランス先端部までの垂
直距離（ｍ）。1. While supplying powdery chrome ore and carbonaceous material into a reaction vessel mainly capable of top-blown and capable of top-bottom blowing, oxygen or oxidation is carried out from a top-blowing lance provided on a shaft core on a molten iron bath surface. A method for obtaining a molten metal by injecting a noble gas from 2.6 Nm 3 / min / t or more to 8.6 Nm 3 / min / t or less, which is the horizontal distance r and height obtained by the following equations (1) and (2). A method for adding powdery chromium ore at the time of molten iron blowing, which comprises adding powdery chromium ore having a particle size of 1 mm or less at a rate of 3.0 m / s or less in a region partitioned by Z. Note r ≦ 0.8r 0 (1) 0.2L ≦ Z ≦ 1.1L (2) where r: horizontal distance (m) from the lance axis of the reaction vessel to the end of the area, r 0 : Horizontal distance from the lance axis of the reaction vessel to the inner wall of the reaction vessel (m), Z: Height starting from the stationary slag surface (m), L: From the stationary slag surface to the tip of the top blowing lance Vertical distance of (m).
る上底吹き可能な反応容器内に供給しつつ、溶鉄浴面上
の軸芯に設けられた上吹きランスから酸素または酸化性
ガスを2.6Nm3/min/t以上8.6Nm3/min/t以下噴射して金属
溶湯を得る方法であって、 1mm以下の粒径の粉状クロム鉱石の添加位置が（１）、
（４）式で求められる領域内であり、かつその位置での
粉状クロム鉱石の下向き流速ＶＤが（３）式を満たすよ
うにして添加することを特徴とする粉状クロム鉱石添加
方法。 記 ｒ≦0.8r0 ………（１） 40≧ＶＤ−Ｖｅ≧５ ………（３） 1.1L＜Ｚ≦1.5L ………（４） ここで、 r:反応容器のランス軸芯から領域側端までの水平距離
（ｍ）、 r0:反応容器のランス軸芯から反応容器内壁までの水平
距離（ｍ）、 ＶＤ：粉状クロム鉱石の下向きの流速（m/s）、 Ｖｅ：粉状クロム鉱石添加位置での炉内排ガスの上向き
の流速（m/s）、 Z:静止状態のスラグ表面を起点とした高さ（ｍ）、 L:静止状態のスラグ表面と上吹きランス先端部までの垂
直距離（ｍ）。2. Oxygen or oxidation is carried out from an upper blowing lance provided on a shaft core on a molten iron bath surface while supplying powdery chrome ore and carbonaceous material into a reaction vessel capable of mainly blowing upper and bottom. A method for obtaining a molten metal by injecting a noble gas from 2.6 Nm 3 / min / t or more to 8.6 Nm 3 / min / t or less, wherein the addition position of powdery chromium ore with a particle size of 1 mm or less is (1),
A method for adding powdery chrome ore, characterized in that the powdery chrome ore is added so that the downward flow velocity V D of the powdery chrome ore at the position is within the region obtained by the formula (4) and satisfies the formula (3). Note r ≦ 0.8r 0 (1) 40 ≧ V D −V e ≧ 5 (3) 1.1L <Z ≦ 1.5L… (4) where r: Lance axis of reaction vessel Horizontal distance from core to edge of region (m), r 0 : Horizontal distance from lance shaft core of reaction vessel to inner wall of reaction vessel (m), V D : Downward flow velocity of powdered chromium ore (m / s) , V e : Upward flow velocity (m / s) of the exhaust gas in the furnace at the pulverized chromium ore addition position, Z: Height from the stationary slag surface as the starting point (m), L: Static slag surface Vertical distance (m) to the tip of the upper blowing lance.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1-215064 | 1989-08-23 | ||
| JP21506489 | 1989-08-23 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03166312A JPH03166312A (en) | 1991-07-18 |
| JPH0733536B2 true JPH0733536B2 (en) | 1995-04-12 |
Family
ID=16666156
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2214318A Expired - Fee Related JPH0733536B2 (en) | 1989-08-23 | 1990-08-15 | Method for adding powdered chromium ore during molten iron blowing |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0733536B2 (en) |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ZA827820B (en) * | 1981-10-30 | 1983-08-31 | British Steel Corp | Production of steel |
| JPS62211347A (en) * | 1986-02-28 | 1987-09-17 | Nippon Kokan Kk <Nkk> | Melting reduction method |
-
1990
- 1990-08-15 JP JP2214318A patent/JPH0733536B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH03166312A (en) | 1991-07-18 |
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