JPH0587571B2 - - Google Patents
Info
- Publication number
- JPH0587571B2 JPH0587571B2 JP59234283A JP23428384A JPH0587571B2 JP H0587571 B2 JPH0587571 B2 JP H0587571B2 JP 59234283 A JP59234283 A JP 59234283A JP 23428384 A JP23428384 A JP 23428384A JP H0587571 B2 JPH0587571 B2 JP H0587571B2
- Authority
- JP
- Japan
- Prior art keywords
- ore
- chromium
- cao
- solvent
- strength
- 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 - Lifetime
Links
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims description 47
- 239000011651 chromium Substances 0.000 claims description 43
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 41
- 229910052804 chromium Inorganic materials 0.000 claims description 41
- 239000002904 solvent Substances 0.000 claims description 36
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 32
- 238000005245 sintering Methods 0.000 claims description 25
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 18
- 239000002994 raw material Substances 0.000 claims description 16
- 238000002156 mixing Methods 0.000 claims description 11
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 5
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 48
- 239000000292 calcium oxide Substances 0.000 description 24
- 235000012255 calcium oxide Nutrition 0.000 description 24
- 238000000034 method Methods 0.000 description 23
- 235000013980 iron oxide Nutrition 0.000 description 20
- 239000000203 mixture Substances 0.000 description 19
- 239000011575 calcium Substances 0.000 description 13
- 230000000694 effects Effects 0.000 description 11
- 229910000604 Ferrochrome Inorganic materials 0.000 description 10
- 239000002893 slag Substances 0.000 description 9
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 8
- 238000003723 Smelting Methods 0.000 description 8
- 230000006866 deterioration Effects 0.000 description 8
- 238000005469 granulation Methods 0.000 description 8
- 230000003179 granulation Effects 0.000 description 8
- 229910052742 iron Inorganic materials 0.000 description 7
- 238000010521 absorption reaction Methods 0.000 description 6
- 239000000428 dust Substances 0.000 description 6
- 239000002245 particle Substances 0.000 description 6
- 238000007796 conventional method Methods 0.000 description 5
- 229910052500 inorganic mineral Inorganic materials 0.000 description 5
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 5
- 238000002844 melting Methods 0.000 description 5
- 230000008018 melting Effects 0.000 description 5
- 235000010755 mineral Nutrition 0.000 description 5
- 239000011707 mineral Substances 0.000 description 5
- 239000000654 additive Substances 0.000 description 4
- 230000000996 additive effect Effects 0.000 description 4
- 238000005054 agglomeration Methods 0.000 description 3
- 230000002776 aggregation Effects 0.000 description 3
- 239000000571 coke Substances 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- 239000000377 silicon dioxide Substances 0.000 description 3
- 238000003860 storage Methods 0.000 description 3
- 235000019738 Limestone Nutrition 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- WYTGDNHDOZPMIW-RCBQFDQVSA-N alstonine Natural products C1=CC2=C3C=CC=CC3=NC2=C2N1C[C@H]1[C@H](C)OC=C(C(=O)OC)[C@H]1C2 WYTGDNHDOZPMIW-RCBQFDQVSA-N 0.000 description 2
- WETINTNJFLGREW-UHFFFAOYSA-N calcium;iron;tetrahydrate Chemical compound O.O.O.O.[Ca].[Fe].[Fe] WETINTNJFLGREW-UHFFFAOYSA-N 0.000 description 2
- 238000006477 desulfuration reaction Methods 0.000 description 2
- 230000023556 desulfurization Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000008187 granular material Substances 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- VBMVTYDPPZVILR-UHFFFAOYSA-N iron(2+);oxygen(2-) Chemical class [O-2].[Fe+2] VBMVTYDPPZVILR-UHFFFAOYSA-N 0.000 description 2
- 239000006028 limestone Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000010450 olivine Substances 0.000 description 2
- 229910052609 olivine Inorganic materials 0.000 description 2
- 230000035699 permeability Effects 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 239000004576 sand Substances 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 239000010456 wollastonite Substances 0.000 description 2
- 229910052882 wollastonite Inorganic materials 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 description 1
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 1
- 239000000920 calcium hydroxide Substances 0.000 description 1
- 235000011116 calcium hydroxide Nutrition 0.000 description 1
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 229910001919 chlorite Inorganic materials 0.000 description 1
- 229910052619 chlorite group Inorganic materials 0.000 description 1
- QBWCMBCROVPCKQ-UHFFFAOYSA-N chlorous acid Chemical compound OCl=O QBWCMBCROVPCKQ-UHFFFAOYSA-N 0.000 description 1
- 229910052681 coesite Inorganic materials 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 229910052906 cristobalite Inorganic materials 0.000 description 1
- 239000010436 fluorite Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- -1 iron ore Chemical compound 0.000 description 1
- LIKBJVNGSGBSGK-UHFFFAOYSA-N iron(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Fe+3].[Fe+3] LIKBJVNGSGBSGK-UHFFFAOYSA-N 0.000 description 1
- SZVJSHCCFOBDDC-UHFFFAOYSA-N iron(II,III) oxide Inorganic materials O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 description 1
- 238000004898 kneading Methods 0.000 description 1
- 239000001095 magnesium carbonate Substances 0.000 description 1
- 235000014380 magnesium carbonate Nutrition 0.000 description 1
- ZLNQQNXFFQJAID-UHFFFAOYSA-L magnesium carbonate Chemical compound [Mg+2].[O-]C([O-])=O ZLNQQNXFFQJAID-UHFFFAOYSA-L 0.000 description 1
- 229910000021 magnesium carbonate Inorganic materials 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 229910052682 stishovite Inorganic materials 0.000 description 1
- 239000000454 talc Substances 0.000 description 1
- 229910052623 talc Inorganic materials 0.000 description 1
- 229910052905 tridymite Inorganic materials 0.000 description 1
- 238000003809 water extraction Methods 0.000 description 1
Landscapes
- Manufacture And Refinement Of Metals (AREA)
Description
産業上の利用分野
本発明はクロム鉱石の焼結方法に関する。更に
詳しくは、媒溶剤の未溶融残留を防止し、成品強
度・歩留りを向上させると共に強度の経時劣化を
防止することのできるクロム鉱石の焼結方法に関
する。
従来の技術
クロム鉱石は、鉄鋼などの添加物であるフエロ
クロムの原料として有用であるが、入手できるク
ロム鉱石原料はその殆どが粉状であるために、フ
エロクロム製造用の製錬炉で使用する場合、飛散
による歩留り低下防止および原料充填層内の通気
性確保の観点から、予め焼結機による塊状化処理
を行うことが多い。
しかしながら、クロム鉱石は溶融温度が1650〜
1700℃と高く、通常焼結機で達成し得る1400℃程
度の温度で溶融、結合し塊状化を図ることは困難
である。このため、クロム鉱石の焼結においては
予めCaO、SiO2並びにMgO等を含有する媒溶剤
を添加することにより易溶融性の組成とし、同時
に添加されるコークスの燃焼熱によりこれら媒溶
剤を溶融してスラグを形成し、溶融媒溶剤をクロ
ム鉱石粒子間に浸透させて、該鉱石間の結合力を
維持していた。クロム鉱石の塊状化処理におい
て、鉱石粒子間の結合力を増大させることは、成
品焼結鉱の歩留りを向上させ、かつ、強度を向上
させる上で極めて重要であり、これまでにCaO、
SiO2並びにMgOを主体とする焼結鉱の各種製造
法が提案されている。例えば、特公昭51−10685
号公報発明、同51−4922号公報発明を例示するこ
とができる。
まず、第１の特公昭50−10685号公報発明は微
粒状のクロム鉱石にコークスを添加し、同じく微
粒状の媒溶剤を添加し混練した後、グリナワルト
式またはドワイトロイド式焼結機で焼結すること
からなるクロム鉱石の焼結方法を開示するもので
あり、ここで使用する媒溶剤は30〜60重量％の
MgOと30〜60重量％のSiO2を含有している。
また、第２の特公昭51−4922号公報発明も同様
なクロム焼結鉱の製造方法を開示しているが、そ
こで使用されている媒溶剤はSiO2を３〜30重量
％、CaOを20〜55重量％及びMgOを10〜30重量
％含有するものである。
発明が解決しようとする問題点
上記の如く、クロム鉱石は微粉状（一般に約
0.5mm程度の平均粒径を有する）であり、従つて
これを製錬炉で還元製錬する際の作業性等を改善
するために、予め塊状化されていた。この塊状化
は媒溶剤並びにコークスと共に焼結炉で焼結する
ことで達成されるが、従来提案されている上記の
ような方法では依然として不十分であり、改良の
余地が残されている。
即ち、上記のような方法において開示された組
成・配合率の媒溶剤では、クロム焼結鉱の成品歩
留りを向上させ、かつ焼結鉱の強度を向上させる
上で十分な効果を達成しているものとはいえず、
さらにまたこのような媒溶剤を用いて得られる成
品は保存中の大気湿分あるいは降雨、粉塵防止散
水中の水分吸蔵により、成品々位が著しく劣化さ
れるという欠点を有していることがわかつた。
そこで、このような従来法の諸欠点を改善する
新たなクロム焼結鉱の製造方法を開発することが
強く望まれており、本発明の目的もこの点にあ
る。
問題点を解決するための手段
本発明者等はクロム焼結鉱の製造方法の上記の
ような現状に鑑み、さらに成品歩留りおよび強度
を改善し、かつ保存中の水分吸蔵などによる強度
の経時劣化を防止することのできる新規なクロム
鉱石の焼結法を開発すべく種々検討、研究した結
果、上記本発明の目的達成のために、媒溶剤に酸
化鉄含有原料を所定量添加し、さらに原料の混
合・造粒操作を２度行うことが極めて有効である
ことを見出し、本発明を完成した。
本発明のクロム鉱石の焼結法は同様にCaO−
SiO2系またはCaOSiO2−MgO系媒溶剤に酸化鉄
含有原料を、該酸化鉄含有原料中ののFeと該媒
溶剤中のCaとの比、Fe／Caが0.08以上となるよ
うに添加し、これを予め混合・造粒し、さらにこ
れにクロム鉱石を添加し再度混合・造粒した後、
焼結機で焼結することおよび粉コークスの添加を
上記２度の混合・造粒工程のいずれかにおいて行
うことを特徴とする。
本発明の方法において、媒溶剤原料、即ち、
CaO源、SiO2源およびMgO源としてはCaO、
SiO2、MgOを主として含有するものであればい
かなるものでもよく、例えばフエロクロム滓、ク
ロムバルブ（クロム鉱石のソーダ焙焼物の水抽出
残渣）、石灰石、螢石、硅砂、苦土橄欖石、蛇紋
石、滑石、緑泥石、その他種々の鉱滓、鉱物等の
材料を挙げることができる。これらは一般に、
CaOとSiO2との総量およびCaOとSiO2とMgOと
の総量がクロム鉱石に対し少なくとも35重量％と
なるような量で添加される。従つて、この条件を
満足するように上記材料から適宜選択し、配合し
て使用される。この媒溶剤の粒度は溶融物形成の
観点から小さい程好ましいが、粒径３mm程度まで
のものであれば困難なしに使用できる。
また、本発明において有利に使用できる鉄酸化
物源としてはFe2O3、Fe3O4、FeOのいずれかを
含有するものであれ特に制限はなく、例えば鉄鉱
石、高炉ダスト、転炉ダスト、電気炉ダスト等の
材料を挙げることができる。
作 用
本発明の目的とするクロム焼結鉱成品歩留り、
強度を改善し、かつ強度の経時劣化を防止するた
めには媒溶剤の組成、成分の適正化を図ることが
きわめて重要である。
クロム焼結鉱製造時の媒溶剤は、焼結鉱製造工
程だけでなく、フエロクロム製錬工程でのスラグ
の溶融性および脱硫性をも考慮してその適正配合
率が決定される。フエロクロム製練時のスラグは
通常第１図の斜線部領域内の組成を有することが
適正であるとされており、焼結鉱製造時の媒溶剤
もこの組成に合致した配合率となる。ところで、
フエロクロム製錬炉は通常1700℃以上の高温度に
保持されるために、第１図で示した範囲内の組成
のスラグであれば十分に溶融することができる。
これに対し、焼結機で達成し得る温度は最高
1400℃程度が限界であり、従つて添加する媒溶剤
中のスラグ分全量を溶融することは困難である。
たとえ溶融したとしても焼結温度下では第１図中
のCaO分の少ないウオラストナイト組成近傍での
一部の溶融に限られる。
一方、本発明で目的とする媒溶剤の配合組成
は、よりCaOに富み、ウオラストナイト組成との
差の分だけCaOが過剰となり、未溶融のまま焼結
鉱中に残留する。残留するカルシウムは殆どが脆
弱な生石灰（CaO）の形であり、従つて第２図お
よび第３図に示したように強度が低く、歩留りが
悪い。また、この生石灰（CaO）は外部環境から
の水分吸蔵によつて消石灰（Ca（OH）2）に変化
し、この時の体積膨張により焼結鉱成品中に亀裂
が発生して第４図に示したような強度劣化を生ず
る。
以上のクロム焼結鉱の呈する諸欠点を改善する
には、焼結鉱中の未溶融CaOの残留を回避するこ
とであり、このためには焼結温度以下で容易に
CaOを溶融同化する物質を添加する必要がある。
さらに、この添加物質はフエロクロム製錬炉にお
いて成品であるフエロクロム合金中に不純物とし
て混入せず、かつスラグの溶融性および脱硫性を
阻害しない元素であればよい。
本発明者等は種々検討を重ねた結果、このよう
な諸要件を満足する添加物が鉄酸化物であること
を見出した。即ち、鉄酸化物のうちヘマタイト
（Fe2O3）はCaOと同化してカルシウムフエライ
ト（nCa Ｏ・Fe2O3）を形成し、マグネタイト
（Fe3O4）およびウスタイト（FeO）はCaOおよ
びSiO2と同化してオリビン（CaO・FeO・SiO2）
を形成する。しかもカルシウムフエライトの溶融
温度は1200℃、オリビンのそれは1100℃であり、
いずれもクロム鉱石の焼結温度1400℃よりも低い
溶融点を有している。
従つて、CaO−SiO2系あるいはCaO−SiO2−
MgO系媒溶剤を用いて製造した場合のクロム焼
結鉱中の過剰CaO（残留する未溶融CaO）は、こ
れら鉄酸化物の添加により消滅し、残留未溶融分
の無い完全に溶融した結合力の強いスラグで構成
された焼結鉱が得られることになる。この結果、
成品焼結鉱の歩留り、強度は向上し、同時に水分
吸蔵による強度の経時劣化も防止することができ
る。
ところで、以上述べた鉄酸化物添加の効果を発
現させるためには、原料段階で媒溶剤中に鉄酸化
物を均一に分散させておく必要がある。これを達
成する方策としては、まず大量の鉄酸化物
（Fe／Caが0.10以上に成る様に調製）を原料に直
接配合添加する方法が考えられる。この方法でも
かなりの効果を達成することができるが、Cr／
Fe比率の低いクロム鉱石では成品としてのフエ
ロクロム合金中のCrの品位を大巾に低下させる
という欠点がある。
このような欠点を補う有効な方法は、媒溶剤と
鉄酸化物とを予め混合・造粒し、次いでこれにク
ロム鉱石を加えて再度混合・造粒した後、焼結機
で焼結することである。この操作を行うに際して
は、粉コークスは２度の混合・造粒操作のいずれ
において添加することもできる。この場合、添加
する鉄酸化物は媒溶剤中だけに集中的に均一分散
するので、少ない添加量（Fe／Caが0.08以上）
で大きな効果が得られる。
従つて、本発明の方法における酸化鉄含有原料
の添加量、即ち媒溶剤中のCaと酸化鉄含有原料
中のFe比、Fe／Caが0.08以上となるような量は
臨界的であり、これらの値以下で使用しても、酸
化鉄成分によるCaOの同化溶融効果を完全に達成
することができない。
実施例
以下添付図面を参照しつつ記載される実施例、
参考例および比較例に従つて、本発明を更に具体
的に説明するが、本発明の範囲はこれら実施例に
より何等制限されない。
参考例
本例においては、従来のクロム焼結鉱が保存中
の大気その他からの水分吸蔵により、強度の経時
劣化を示すことを実証する。
第１表に示す組成のCaO、SiO2、MgO系の原
料からなる媒溶剤を使用し、これにクロム鉱石と
粉コークスとを加えて、常法に従つて焼結鍋装置
で焼成して、強度（タンブラーJIS法）および歩
留り（＋５mmの成品比率）を測定し、結果を第２
図および第３図に示した。
INDUSTRIAL APPLICATION FIELD OF THE INVENTION The present invention relates to a method for sintering chromium ore. More specifically, the present invention relates to a method for sintering chromium ore that can prevent unmelted solvents from remaining, improve product strength and yield, and prevent deterioration of strength over time. Conventional technology Chromium ore is useful as a raw material for ferrochrome, which is an additive for steel, etc. However, since most of the available chromium ore raw materials are in powder form, it is difficult to use them in smelting furnaces for producing ferrochrome. From the viewpoint of preventing a decrease in yield due to scattering and ensuring air permeability in the raw material packed bed, agglomeration treatment is often performed in advance using a sintering machine. However, chromium ore has a melting temperature of 1650 ~
The temperature is as high as 1,700°C, and it is difficult to melt, combine, and form a lump at the temperature of about 1,400°C, which can be achieved with a normal sintering machine. For this reason, when sintering chromium ore, a solvent containing CaO, SiO 2 , MgO, etc. is added in advance to make it easily meltable, and these solvents are melted by the combustion heat of coke that is added at the same time. A slag was formed and a solvent solvent was infiltrated between the chromium ore particles to maintain the bond between the ore particles. In the agglomeration process of chromium ore, increasing the bonding force between ore particles is extremely important for improving the yield and strength of finished sintered ore.
Various methods for producing sintered ore mainly composed of SiO 2 and MgO have been proposed. For example, Tokuko Sho 51-10685
The invention disclosed in Japanese Patent Application Publication No. 51-4922 can be exemplified. First, the invention disclosed in Japanese Patent Publication No. 50-10685 involves adding coke to fine grained chromium ore, adding fine grained solvent, kneading it, and then sintering it in a Greenawalt type or Dwight Lloyd type sintering machine. The present invention discloses a method for sintering chromium ore, in which the solvent used is 30 to 60% by weight.
Contains MgO and 30-60% by weight SiO2 . In addition, the second invention disclosed in Japanese Patent Publication No. 51-4922 discloses a similar method for producing chromium sintered ore, but the solvent used therein is 3 to 30% by weight of SiO 2 and 20% by weight of CaO. -55% by weight and 10-30% by weight of MgO. Problems to be solved by the invention As mentioned above, chromium ore is in the form of fine powder (generally about
It has an average particle size of about 0.5 mm), and therefore, it has been agglomerated in advance in order to improve workability when reducing and smelting it in a smelting furnace. This agglomeration is achieved by sintering in a sintering furnace together with a solvent and coke, but the previously proposed methods described above are still insufficient, and there is still room for improvement. That is, the solvent having the composition and blending ratio disclosed in the method described above achieves sufficient effects in improving the yield of chromium sintered ore and improving the strength of sintered ore. It cannot be called a thing,
Furthermore, it has been found that products obtained using such solvents have the disadvantage that the quality of the products is significantly deteriorated due to atmospheric moisture or rainfall during storage, and water absorption during dust prevention spraying. Ta. Therefore, it is strongly desired to develop a new method for producing chromium sintered ore that improves the various drawbacks of the conventional method, and this is also the purpose of the present invention. Means for Solving the Problems In view of the above-mentioned current state of the production method of chromium sintered ore, the present inventors have further improved the product yield and strength, and have also attempted to solve the problem of deterioration of strength over time due to moisture absorption during storage, etc. As a result of various studies and researches to develop a new chromium ore sintering method that can prevent The present invention was completed based on the discovery that it is extremely effective to perform the mixing and granulation operations twice. The chromium ore sintering method of the present invention is also CaO−
An iron oxide-containing raw material is added to a SiO 2 -based or CaOSiO 2 -MgO-based solvent such that the ratio of Fe in the iron oxide-containing raw material to Ca in the solvent, Fe/Ca, is 0.08 or more. After mixing and granulating this in advance, adding chromium ore and mixing and granulating it again,
It is characterized in that sintering with a sintering machine and addition of coke powder are performed in either of the above two mixing/granulation steps. In the method of the present invention, the solvent raw material, i.e.
CaO, SiO 2 source and MgO source include CaO,
Any material may be used as long as it mainly contains SiO 2 and MgO, such as ferrochrome slag, chromium bulb (residue of water extraction from soda roasting of chromium ore), limestone, fluorite, silica sand, magnesite, and serpentine. , talc, chlorite, and various other slags and minerals. These are generally
The amounts are added such that the total amount of CaO and SiO 2 and the total amount of CaO, SiO 2 and MgO is at least 35% by weight relative to the chromium ore. Therefore, the above-mentioned materials are appropriately selected and blended to satisfy this condition. The particle size of this solvent is preferably as small as possible from the viewpoint of melt formation, but any particle size up to about 3 mm can be used without difficulty. Further, iron oxide sources that can be advantageously used in the present invention are not particularly limited as long as they contain Fe 2 O 3 , Fe 3 O 4 , or FeO, such as iron ore, blast furnace dust, converter dust, etc. , electric furnace dust, and the like. Effect The yield of chromium sintered mineral products targeted by the present invention,
In order to improve strength and prevent deterioration of strength over time, it is extremely important to optimize the composition and components of the solvent. The appropriate blending ratio of the solvent used in producing chromium sintered ore is determined not only in the sintered ore production process, but also in consideration of the meltability and desulfurization properties of slag in the ferrochrome smelting process. It is generally considered appropriate for the slag during ferrochrome smelting to have a composition within the shaded area in FIG. 1, and the proportion of the solvent used in producing sintered ore also matches this composition. by the way,
Since a ferrochrome smelting furnace is normally maintained at a high temperature of 1700° C. or higher, slag having a composition within the range shown in FIG. 1 can be sufficiently melted. In contrast, the temperature that can be achieved with a sintering machine is the highest
The limit is about 1400°C, and therefore it is difficult to melt the entire amount of slag in the added solvent.
Even if it were to melt, under the sintering temperature, it would only be partially melted near the wollastonite composition shown in Figure 1 with a low CaO content. On the other hand, the blended composition of the solvent targeted in the present invention is richer in CaO, and CaO is in excess due to the difference from the wollastonite composition, and remains unmelted in the sintered ore. The remaining calcium is mostly in the form of brittle quicklime (CaO) and therefore has low strength and poor yield as shown in FIGS. 2 and 3. In addition, this quicklime (CaO) changes to slaked lime (Ca(OH) 2 ) by absorbing moisture from the external environment, and the volumetric expansion at this time causes cracks to occur in the sintered mineral product, as shown in Figure 4. This results in strength deterioration as shown. In order to improve the above-mentioned drawbacks of chromium sintered ore, it is necessary to avoid the unmelted CaO remaining in the sintered ore.
It is necessary to add a substance that melts and assimilates CaO.
Further, this additive substance may be any element as long as it does not mix as an impurity into the ferrochrome alloy, which is a finished product in the ferrochrome smelting furnace, and does not inhibit the melting properties and desulfurization properties of the slag. As a result of various studies, the present inventors have discovered that iron oxide is an additive that satisfies these various requirements. That is, among iron oxides, hematite (Fe 2 O 3 ) is assimilated with CaO to form calcium ferrite (nCa O Fe 2 O 3 ), and magnetite (Fe 3 O 4 ) and wustite (FeO) are combined with CaO and Assimilated with SiO 2 to form olivine (CaO, FeO, SiO 2 )
form. Moreover, the melting temperature of calcium ferrite is 1200℃ and that of olivine is 1100℃.
Both have melting points lower than the 1400°C sintering temperature of chromium ore. Therefore, CaO−SiO 2 system or CaO−SiO 2 −
Excess CaO (residual unmelted CaO) in chromium sintered ore produced using MgO-based solvents is eliminated by the addition of these iron oxides, resulting in a completely melted bond with no residual unmelted content. This results in sintered ore composed of strong slag. As a result,
The yield and strength of the finished sintered ore are improved, and at the same time, deterioration of strength over time due to moisture absorption can be prevented. By the way, in order to bring out the effect of adding iron oxide as described above, it is necessary to uniformly disperse the iron oxide in the solvent at the raw material stage. One possible way to achieve this is to add a large amount of iron oxide (prepared so that the Fe/Ca ratio is 0.10 or more) directly to the raw material. This method can also achieve considerable effects, but Cr/
A chromium ore with a low Fe ratio has the disadvantage of greatly reducing the quality of Cr in the finished ferrochrome alloy. An effective method to compensate for these drawbacks is to mix and granulate the solvent and iron oxide in advance, then add chromium ore, mix and granulate it again, and then sinter it in a sintering machine. It is. When performing this operation, coke powder can be added in either of the two mixing and granulation operations. In this case, the added iron oxide is intensively and uniformly dispersed only in the solvent, so the amount added is small (Fe/Ca is 0.08 or more).
You can get a big effect. Therefore, the amount of the iron oxide-containing raw material added in the method of the present invention, that is, the amount such that the ratio of Ca in the solvent to Fe in the iron oxide-containing raw material, Fe/Ca, is 0.08 or more is critical; Even if it is used below the value of , the effect of assimilation and melting of CaO by the iron oxide component cannot be completely achieved. Examples Examples described below with reference to the attached drawings,
The present invention will be explained in more detail according to Reference Examples and Comparative Examples, but the scope of the present invention is not limited in any way by these Examples. Reference Example This example demonstrates that conventional chromium sintered ore exhibits deterioration in strength over time due to absorption of moisture from the atmosphere and other sources during storage. Using a solvent consisting of CaO, SiO 2 , and MgO-based raw materials having the composition shown in Table 1, chromium ore and coke powder are added thereto, and the mixture is sintered in a sintering pot device according to a conventional method. Measure the strength (tumbler JIS method) and yield (product ratio of +5 mm) and compare the results with the second one.
It is shown in FIG.
【表】
第２図および第３図の結果から明らかな如く、
通常鉄焼結鉱の平均的な強度は65％、歩留りは75
％であるが、CaO、SiO2、MgO系媒溶剤で焼結
したクロム焼結鉱の場合は著しく強度および歩留
りが悪い。さらにこれ等の成品焼結鉱にスプレー
で水を添加すると、第４図に示すように、クロム
焼結鉱は極端に強度が低下することがわかる。
CaO、SiO2、MgO系媒溶剤を用いて製造したク
ロム焼結鉱はこのような各種欠点を有し、改善が
必要である。
実施例 １
直径300mm、高さ500mmの焼結鍋試験により鉄酸
化物添加効果を確認した。使用した原料の組成は
第１表に示したものと同一である。各原料の配合
はクロム鉱石：粉コークス：石灰石：硅砂：蛇紋
粉＝55：５：22：10：８で一定とし、これに対し
鉄鉱石あるいは転炉ダストを外比で添加した。
これら鉄鉱石および転炉ダストの成分並びに組
成は以下の第２表に示す通りである。[Table] As is clear from the results in Figures 2 and 3,
The average strength of normal iron sinter is 65% and the yield is 75%.
%, but in the case of chromium sintered ore sintered with CaO, SiO 2 , and MgO-based solvents, the strength and yield are significantly poor. Furthermore, when water is added by spray to these finished sintered ores, the strength of the chromium sintered ores is extremely reduced, as shown in FIG. 4.
The chromium sintered ore produced using CaO, SiO 2 , and MgO-based solvents has various drawbacks as described above, and improvements are required. Example 1 The effect of adding iron oxide was confirmed by a sintering pot test with a diameter of 300 mm and a height of 500 mm. The composition of the raw materials used was the same as shown in Table 1. The composition of each raw material was kept constant at chromium ore: coke powder: limestone: silica sand: serpentine powder = 55:5:22:10:8, to which iron ore or converter dust was added at an external ratio. The components and compositions of these iron ores and converter dust are shown in Table 2 below.
【表】
混合・造粒は第５図に示したように、本発明の
方法で実施した。
かくして得た、クロム焼結鉱成品につき各種物
性の測定を行い、第６図〜第９図にその結果を示
した。
第６図および第７図は、夫々本発明法の造粒法
で混合・造粒した際の、酸化鉄含有原料添加の強
度および歩留りに対する効果を示すものであり、
添加量が増大するに従い、強度並びに歩留りが大
巾に増大することがわかる。比較のために鉄酸化
物を添加しなかつた場合の結果も併せてプロツト
した。
一方、第８図は第６図に示した鉄鉱石をFe／
Ca比率が0.09となるように添加した焼結鉱の水分
吸蔵に対する強度劣化効果を示したものである。
鉄鉱石を添加した焼結鉱は殆ど劣化しないこと
が、第８図の結果から理解することができる。
また、第９図は鉄酸化物として鉄鉱石を添加し
た際の本発明法の造粒方法の効果を示したもので
ある。
クロム製錬炉は通常電気炉が用いられるが、操
業上通気性を阻害しないために必要最低強度60
（タンブラー指数）を達成する必要があり、従つ
て第９図より明らかな如く、鉄酸化物の下限臨界
添加量はFe／Ca比率0.08でなければならないこ
とがわかる。
発明の効果
かくして、詳しく説明したように、本発明の焼
結法に従つて、所定比率（Fe／Ca）の酸化鉄含
有原料を媒溶剤に添加し、さらに、混合・造粒操
作を２度行うことにより、クロム焼結鉱成品中に
残留する恐れのある媒溶剤の未溶融部分を完全に
焼結温度下でなくすことが可能となり、その結果
該成品の歩留り、強度を大巾に向上し得るばかり
でなく、外的環境からの水分吸蔵に基く強度の経
時劣化の問題も完全に解決することが可能となつ
た。
従つて、本発明のクロム鉱石の焼結法は、鉄鋼
等に対する添加物であるフエロクロムの製造技術
の改良において極めて有用な発明であるといえよ
う。[Table] Mixing and granulation were performed according to the method of the present invention as shown in FIG. Various physical properties of the chromium sintered mineral product thus obtained were measured, and the results are shown in FIGS. 6 to 9. Figures 6 and 7 show the effect of adding iron oxide-containing raw materials on strength and yield when mixed and granulated using the granulation method of the present invention, respectively.
It can be seen that as the amount added increases, the strength and yield increase significantly. For comparison, the results when no iron oxide was added were also plotted. On the other hand, Figure 8 shows the iron ore shown in Figure 6 as Fe/
This figure shows the strength deterioration effect on moisture absorption of sintered ore with Ca ratio added to 0.09.
It can be understood from the results shown in FIG. 8 that the sintered ore to which iron ore has been added hardly deteriorates. Moreover, FIG. 9 shows the effect of the granulation method of the present invention when iron ore is added as iron oxide. Electric furnaces are usually used for chromium smelting furnaces, but the minimum strength required is 60 to avoid impeding air permeability during operation.
Therefore, as is clear from FIG. 9, the lower critical addition amount of iron oxide must be an Fe/Ca ratio of 0.08. Effects of the Invention Thus, as explained in detail, according to the sintering method of the present invention, a predetermined ratio (Fe/Ca) of an iron oxide-containing raw material is added to a solvent, and the mixing and granulation operations are further carried out twice. By doing so, it is possible to completely eliminate the unmelted portion of the solvent that may remain in the chromium sintered mineral product at the sintering temperature, and as a result, the yield and strength of the product are greatly improved. Not only has it been possible to completely solve the problem of strength deterioration over time due to moisture absorption from the external environment. Therefore, it can be said that the chromium ore sintering method of the present invention is an extremely useful invention in improving the manufacturing technology of ferrochrome, which is an additive for steel and the like.
第１図はCaO−SiO2−MgO系媒溶剤の適正配
合率を示す平衡状態図であり、第２図は従来法に
おける媒溶剤の成分構成に対し、得られる成品焼
結鉱の強度をプロツトしたグラフであり、第３図
は同様に従来法における媒溶剤の成分構成に対
し、焼結鉱の＋５mm成品比率をプロツトしたグラ
フであり、第４図は従来の成品焼結鉱の水分吸蔵
による強度の経時劣化の状況を示すグラフであ
り、第５図は本発明のクロム鉱石の焼結法の各工
程を示したフロー図であり、第６図および第７図
は夫々媒溶剤と鉄酸化物の成分構成（Fe／Ca）
に対し、強度および歩留りをプロツトしたグラフ
であり、第８図は本発明の方法により得られた成
品焼結鉱の水分吸蔵に伴う強度変化の状況を示す
グラフであり、第９図は第６図と同様な関係をプ
ロツトしたものであり、造粒法の違いに基く
Fe／Caに対する強度変化の相違を示すグラフで
ある。
Figure 1 is an equilibrium state diagram showing the appropriate blending ratio of the CaO-SiO 2 -MgO solvent, and Figure 2 is a plot of the strength of the resulting sintered ore with respect to the component composition of the solvent in the conventional method. Similarly, Figure 3 is a graph plotting the +5mm product ratio of sintered ore against the component composition of the solvent in the conventional method, and Figure 4 is a graph that plots the ratio of sintered ore products with a +5 mm product ratio compared to the composition of the solvent in the conventional method. FIG. 5 is a flow diagram showing each step of the chromium ore sintering method of the present invention, and FIGS. 6 and 7 are graphs showing how the strength deteriorates over time. Composition of objects (Fe/Ca)
8 is a graph plotting the strength and yield of sintered ore obtained by the method of the present invention, and FIG. This is a plot of the same relationship as in the figure, based on differences in granulation methods.
It is a graph showing the difference in intensity change with respect to Fe/Ca.
Claims (1)
溶剤に酸化鉄含有原料を、該酸化鉄含有原料中の
Feと該媒溶剤中のCaとの比、Fe／Caが0.08以上
となるように添加し、これを予め混合・造粒した
後、さらにこれにクロム鉱石を添加後、再度混
合・造粒した後、焼結機で焼結し、かつ粉コーク
スの添加を上記２度の混合・造粒工程のいずれか
の工程において行うことを特徴とするクロム鉱石
の焼結方法。1 Adding an iron oxide-containing raw material to a CaO-SiO 2 -based or CaO-SiO 2 -MgO-based solvent,
Fe was added so that the ratio of Fe to Ca in the solvent, Fe/Ca, was 0.08 or more, and this was mixed and granulated in advance, and then chromium ore was added to this, and then mixed and granulated again. Chromium ore is then sintered in a sintering machine, and coke powder is added in one of the two mixing and granulating steps described above.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23428384A JPS61113732A (en) | 1984-11-07 | 1984-11-07 | Sintering method of chrome ore |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23428384A JPS61113732A (en) | 1984-11-07 | 1984-11-07 | Sintering method of chrome ore |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61113732A JPS61113732A (en) | 1986-05-31 |
| JPH0587571B2 true JPH0587571B2 (en) | 1993-12-17 |
Family
ID=16968548
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP23428384A Granted JPS61113732A (en) | 1984-11-07 | 1984-11-07 | Sintering method of chrome ore |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61113732A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100308830B1 (en) * | 1997-07-18 | 2002-04-17 | 이구택 | Sintered ore manufacturing method for improving recovery ratio of sintered ore |
| CN105063348A (en) * | 2015-08-19 | 2015-11-18 | 山西太钢不锈钢股份有限公司 | Fluxed MgO pellet ore production method |
| JP7234768B2 (en) * | 2019-04-16 | 2023-03-08 | 日本製鉄株式会社 | Preheating method of immersion nozzle |
-
1984
- 1984-11-07 JP JP23428384A patent/JPS61113732A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61113732A (en) | 1986-05-31 |
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