KR910006014B1 - Pellet of high chrome ore - Google Patents

Pellet of high chrome ore Download PDF

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KR910006014B1
KR910006014B1 KR1019880017833A KR880017833A KR910006014B1 KR 910006014 B1 KR910006014 B1 KR 910006014B1 KR 1019880017833 A KR1019880017833 A KR 1019880017833A KR 880017833 A KR880017833 A KR 880017833A KR 910006014 B1 KR910006014 B1 KR 910006014B1
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chromium ore
ore
chromium
pellets
pellet
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KR900010022A (en
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김태동
문석민
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재단법인 산업과학기술연구소
백덕현
포항종합제철 주식회사
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    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22BPRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B1/00Preliminary treatment of ores or scrap
    • C22B1/14Agglomerating; Briquetting; Binding; Granulating

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Abstract

A method for chromium ore pellet to make pre-reduced chromium ore pellet is characterized by adding Mg3Si2O5(OH)4 of 3-7 wt.% to a mixture of chromium ore, bentonite, and cokes. In above method, wt.% of chromium ore and bentonite are 88-94 and 3-5, respectively, and wt.% of cokes is 14-20 to a mixture of chromium ore, bentonite, and Mg3Si2O5(OH)4. In this method, metallization efficency can be promoted by adding a cheap Mg3Si2O5(OH)4 to chromium ore pellets.

Description

고환원 크롬광석 펠릿High Reduction Chrome Ore Pellets

본 발명은 예비환원 크롬광석 펠릿을 제조하기 위한 크롬광석 펠릿에 관한 것으로서, 보다 상세하게는, 크롬광석과 코크스 분말을 혼합한 크롬광석 펠릿에 별도의 부원료가 첨가됨으로서 금속화율이 향상되는 고환원 크롬광석 펠릿에 관한 것이다.The present invention relates to chromium ore pellets for the production of pre-reduced chromium ore pellets, and more particularly, high reduction chromium in which the metallization rate is improved by the addition of a separate raw material to the chromium ore pellets mixed with chromium ore and coke powder. Relates to ore pellets.

스텐레스 제조시의 원료로 사용되는 Fe-Cr 합금철의 일반적인 제조법으로는 크롬광석과 코크스를 전기로에 장입하여 제련하는 방법과 크롬광석을 전기로이외의 가열장치에 의하여 미리 부분환원하고 이것을 전기로에서 제련하여 최종적으로는 Fe-Cr로 제조하는 방법들이 있다.The general manufacturing method of Fe-Cr alloy iron used as a raw material for stainless steel manufacturing is to charge smelting chrome or coke in an electric furnace and to partially reduce the chrome ore by a heating device other than an electric furnace and to smelt it in an electric furnace. Finally, there are methods of producing Fe-Cr.

후자에 의한 방법으로 Fe-Cr을 전기로에서 제련할 경우, 전력원단위를 대폭적으로 절감할 수 있고 생산성 및 회수율을 높일 수 있다는 것은 공지된 기술이다. 이와 같이 크롬광석을 펠릿상태로 하여 미리 부분환원한 것을 예비환원 펠릿이라 하며, 예비환원법으로는 여러 가지가 제안되고 있으나, 실용적으로 공업화되고 있는 방법은 로타리킬른에서 소성환원하는 방법뿐이다.In the case of smelting Fe-Cr in an electric furnace by the latter method, it is known that the power source unit can be greatly reduced and productivity and recovery rate can be improved. In this way, the partial reduction of chromium ore in the form of pellets is called pre-reduction pellets, and various reduction methods have been proposed. However, the only industrially industrialized methods are plastic reduction in rotary kilns.

종래의 예비환원 크롬광석 펠릿의 제조법은 통상 74μ이하인 입자가 약 80% 이상 되도록 미 분쇄한 광석과 코크스에 벤토나이트등의 점결제를 혼합하고, 펠리타이저에서 수첨가하여 생펠릿을 조립한 다음, 로타리 킬른에 장입하여 1200-1450℃로 소성환원하는 것이다. 이렇게 제조된 실용적인 예비환원 크롬광석 펠릿의 금속화율은 약 55-65%로써, 철광석 펠릿의 경우보다 훨씬 낮은 금속화율을 나타내는데 이는 크롬광석 자체가 환원되기 어려운 물질이기 때문이다. 여기서 금속화율은 크롬광석중의 철 및 크롬성분과 결합하고 있는 산소량과 환원에 의하여 제거된 산소량과의 비율로 계산한 값으로, 아래식에 의하여 계산한다.Conventional methods for preparing pre-reduced chromium ore pellets are usually mixed with unpulverized ore and coking with bentonite and the like, so that particles having a diameter of 74 μm or less are about 80% or more, and granulated raw pellets by adding water in a pelletizer. It is charged into a rotary kiln and plastically reduced to 1200-1450 ° C. The metallization rate of the practical pre-reduced chromium ore pellets thus prepared is about 55-65%, which is much lower than that of iron ore pellets because the chromium ore itself is difficult to reduce. Here, the metallization rate is calculated by the ratio between the amount of oxygen bonded to iron and chromium components in the chromium ore and the amount of oxygen removed by reduction, and is calculated by the following equation.

Figure kpo00001
Figure kpo00001

따라서, 코크스를 혼합한 크롬광석 펠릿의 금속화율을 개선하기 위한 방법으로 펠릿중의 SiO2함량증가, 붕산염등의 첨가 혹은 Fe-Ni의 제련슬래그의 첨가(일본특허공보 : 85-53731, 고환원 크롬광석 펠릿의 제조법)방법등이 제안되고 있다.Therefore, as a method for improving the metallization rate of chromium ore pellets mixed with coke, an increase in the content of SiO 2 in the pellets, addition of borate salts, or addition of smelting slag of Fe-Ni (Japanese Patent Publication: 85-53731, High Reduction) Method of manufacturing chrome ore pellets) has been proposed.

그러나, 상기 방법들의 경우 붕산염등은 화공약품으로서 가격이 고가이고, Fe-Ni 제련슬래그등은 구득하기 어려운 문제점들을 내포하고 있다. 본 발명은 사문암의 첨가량을 종래의 규석과 동일한 비율로 제반문제점들을 해소하기 위해 예비환원 크롬광석 펠릿을 제조할 때 크롬광석 펠릿의 배합원료로 SiO2원인 규석대신에 국내에서 쉽게 구할 수 있는 사문암(Mg3Si2O5(OH)4)을 펠릿의 배합원료로 첨가하므로서 예비환원 펠릿의 금속화율을 향상시킬 수 있는 고환원 크롬광석 펠릿을 제공하고자 하는데, 그 목적이 있다.However, in the above methods, borate and the like are expensive as chemicals, and Fe-Ni smelting slag contains problems that are difficult to obtain. The present invention is a serpentine rock that can be easily obtained domestically in place of silica 2 cause silica as a raw material of chromium ore pellets when preparing pre-reduced chromium ore pellets in order to solve the problems in the same ratio as the conventional silica. An object of the present invention is to provide a high-reduction chromium ore pellet which can improve the metallization rate of the pre-reduced pellet by adding Mg 3 Si 2 O 5 (OH) 4 ) as a blending material of the pellet.

이하에서 본 발명을 좀더 상세하게 설명하면 다음과 같다. 본 발명은 예비환원 크롬광석 펠릿을 제조하기 위한 크롬광석 펠릿에 있어서, 크롬광석, 벤토나이트 및 코크스로 이루어진 통상의 크롬광석 펠릿 배합원료에 사문암이 3-7중량% 첨가된 고환원 크롬광석 펠릿에 관한 것이다.Hereinafter, the present invention will be described in more detail. The present invention relates to high-reduced chrome ore pellets in which chromite ore is added to the chromium ore pellets for preparing pre-reduced chrome ore pellets, wherein serpentine is added to a conventional chromium ore pellet blended material consisting of chromium ore, bentonite and coke. will be.

상기에서, 크롬광석은 88-94중량%, 벤토나이트는 3-5중량%, 사문암은 3-7중량%, 코크스는 크롬광석, 벤토나이트 및 사문암으로 이루어지는 배합원료에 대하여 14-20중량%가 바람직하다.In the above, chromium ore is 88-94% by weight, bentonite is 3-5% by weight, serpentine is 3-7% by weight, coke is preferably 14-20% by weight relative to the blending material consisting of chromium ore, bentonite and serpentine. .

상기 크롬광석으로는 고환원 크롬광석 펠릿의 원료로 통상 사용되는 것이라면 어느 것이나 가능하며, 보다 바람직한 크롬광석으로는 25-35중량%의 T.Cr, 15-30중량%의 T.Fe 및 기타 Al2O3, MgO 등을 함유한 것을 들 수 있다.The chromium ore can be any one commonly used as a raw material of high-reduction chromium ore pellets, and more preferred chromium ore is 25-35% by weight of T.Cr, 15-30% by weight of T.Fe and other Al. 2 O 3, it may be mentioned containing MgO and the like.

상기 크롬광석중의 T.Cr 및 T.Fe의 함량은 많을수록 좋으나, 35중량% 이상의 T.Cr 및 30중량%이상의 T.Fe를 함유한 광석을 준비하는데는 많은 비용이 수반되며, 그 함량이 너무 적으면 회수율이 나빠 경제성이 떨어지게 된다.The higher the content of T.Cr and T.Fe in the chromium ore, the better, but it is expensive to prepare an ore containing 35% by weight or more of T.Cr and 30% or more by weight of T.Fe. Too little can result in poor recovery and poor economic efficiency.

그리고, 상기 크롬광석의 양은 88-94중량%가 바람직한데, 그 양이 88중량% 이하인 경우에는 크롬광석 펠릿중의 T.Cr 및 T.Fe의 함량이 너무 낮아 Fe-Cr 합금철 제조시 회수율이 떨어지고, 94중량% 이상인 경우에는 환원율이 떨어지게 된다.In addition, the amount of chromium ore is preferably 88-94% by weight, when the amount is 88% by weight or less, the content of T.Cr and T.Fe in the chromium ore pellets is too low to recover the Fe-Cr alloy If the fall, if the 94% by weight or more will be reduced.

상기 벤토나이트의 첨가량은 통상적인 조업에서와 같이 원료조업조건에 따라 탄력적으로 결정되며, 보다 바람직한 첨가량은 3-5중량%이며, 3중량%이하에서는 점결력이 떨어지며, 5중량%이상에서는 슬래그양이 증가된다.The addition amount of the bentonite is elastically determined according to the raw material operating conditions, as in the usual operation, more preferably the addition amount is 3-5% by weight, less than 3% by weight caking force, more than 5% by weight slag amount Is increased.

환원제인 코크스의 첨가량은 크롬광석중의 크롬 및 철의 산화물의 환원에 필요한 환원당량의 약 65-100%에 해당하는 양이 바람직한데, 본 발명에 있어서, 바람직한 크롬광석중의 T.Cr 및 T.Fe량을 감안해 볼 때 그 첨가량은 14-20중량%가 바람직하다.The amount of coke added as a reducing agent is preferably about 65-100% of the reduction equivalent required for the reduction of chromium and iron oxides in the chromium ore. In the present invention, T.Cr and T in the preferred chromium ore are preferred. In view of the amount of Fe, the amount of addition is preferably 14-20% by weight.

상기 펠릿에 첨가된 사문암은 800℃이상의 고온이되면 사문암의 분해반응이 진행되어 먼저 결합수가 제거되고 엔스태타이트(MgSiO3), 포스테라이트(Mg2SiO4) 및 SiO2등이 생성된다. 이와 같이 SiO2가 생성되면 종래의 규석첨가시 SiO2가 크로마이트중의 MgO 및 Al2O3를 흡수하여 크로마이트의 환원성을 촉진시키는 효과와 동일한 작용에 의하여 규석이나 사문암 무첨가시보다 금속화율이 향상되는 것이다. 그러나 사문암첨가가 동량의 규석첨가시보다 금속화율이 높다는 원인에 대하여는 아직 해석하기가 곤란한 실정이다.When the serpentine is added to the pellets at a high temperature of 800 ° C. or more, the decomposition reaction of the serpentine proceeds, so that the binding water is firstly removed, and thus, the enanthate (MgSiO 3 ), forsterite (Mg 2 SiO 4 ), and SiO 2 are produced. As such, when SiO 2 is produced, the metallization rate is higher than that of silica or serpentine, due to the same effect as that of SiO 2 absorbing MgO and Al 2 O 3 in chromite to promote reducibility of chromite. To improve. However, it is still difficult to interpret the reason why the addition of serpentine rock has a higher metallization rate than the addition of silica.

다만, 사문암의 분해생성물인 SiO2의 효과이외에도, 결합수의 소실에 의한 펠릿내 공극의 형성 즉, 환원 가스의 유통을 촉진시킬 수 있는 통로의 확대에 의하여 금속화율을 개선시키거나, 불순성분이 혼재된 상태에서의 상기 규산염(엔스태타이트, 포스테라이트)의 불순물흡수 작용등에 의한 것이라고 추정된다.However, in addition to the effect of SiO 2 , which is a decomposition product of serpentine rock, the metallization rate may be improved or impurities may be formed due to the formation of voids in the pellets due to the loss of the binding water, that is, the expansion of the passage which may promote the flow of reducing gas. It is presumed that it is due to the impurity absorbing action of the silicate (anthite, forsterite) in the mixed state.

따라서, 본 발명에서와 같이 사문암 첨가펠릿을 환원시킬 경우 용제의 무첨가시 및 규석첨가시에 비하여 펠릿의 금속화율이 향상된다.Therefore, when the serpentine-added pellets are reduced as in the present invention, the metallization rate of the pellets is improved as compared with the absence of the solvent and the addition of the silica.

상기 사문암은 SiO2및 MgO를 주성분으로하는 것으로서, 본 발명에 있어서 바람직하게 적용될 수 있는 것은 30-45중량%의 SiO2및 25-40중량%의 MgO를 함유하는 것이다.The serpentine is mainly composed of SiO 2 and MgO, and it can be preferably applied in the present invention to contain 30-45 wt% SiO 2 and 25-40 wt% MgO.

본 발명의 크롬광석 펠릿은 상기와 같이 배합되는 배합원료를 통상의 방법 즉, 74μ이하인 입자가 80%이상이되도록 미세하게 분쇄한 크롬광석, 코크스, 벤토나이트와 사문암을 혼합하고 펠리타이저에서 수첨가하여 조립하므로서 제조되며, 이렇게 제조된 본 발명의 크롬광석 펠릿은 로타리킬른에 장입되어 킬른의 건조대(-400℃), 예열대(400-800℃) 및 환원대(1200-1450℃)를 연속적으로 이동하면서 약 4시간만에 배출되어 최종산물인 예비환원 펠릿이 된다.In the chromium ore pellet of the present invention, the blended raw materials blended as described above are mixed in a conventional manner, that is, finely pulverized chromium ore, coke, bentonite and serpentine are added to the pelletizer to make 80% or more of particles less than 74μ. It is manufactured by assembling, and thus the chromium ore pellets of the present invention are charged in a rotary kiln to continuously move the kiln's drying table (-400 ° C), preheating table (400-800 ° C) and reducing table (1200-1450 ° C). It is discharged in about 4 hours and becomes the final product preliminary pellet.

이하 실시예를 통하여 본 발명을 상세히 설명한다.Hereinafter, the present invention will be described in detail through examples.

[실시예]EXAMPLE

하기 표 1의 화학성분을 갖는 배합원료를 하기 표 2와 같은 배합비로 배합하여 약 12mm의 크기를 갖는 펠릿을 제조하고 이 펠릿을 수평관상로에 장입하고 통전하여 노내분위기의 온도에 대한 승온속도를 10℃/min으로 하여 1200℃로 승온하고 이온도에서 2시간 유지한 다음(이때, 노내분위기는 펠릿에 첨가된 환원제인 코우크스의 산화손실을 방지하기 위하여 질소분위기로 유지하였다).Formulated raw materials having the chemical composition of Table 1 in the following mixing ratio to prepare a pellet having a size of about 12mm and charging the pellet in a horizontal tube furnace and energized to increase the rate of temperature rise in the atmosphere of the furnace atmosphere The temperature was raised to 1200 ° C. at 10 ° C./min and maintained at ionicity for 2 hours (at this time, the furnace atmosphere was kept in a nitrogen atmosphere to prevent oxidation loss of coke, a reducing agent added to the pellet).

펠릿의 금속화율을 측정하여 하기 표 2에 나타내었다.The metallization rate of the pellets was measured and shown in Table 2 below.

[표 1]TABLE 1

Figure kpo00002
Figure kpo00002

[표 2]TABLE 2

Figure kpo00003
Figure kpo00003

상기에서 사용된 코크스의 고정탄소(Fixed Cabon)함량은 87.78중량%이고, 코크스의 첨가량은 크롬광석중의 산화철 및 산화크롬성분이 90% 환원(산화크롬은 Cr2O3가 Cr3C2로, 산화철은 FeO가 Fe로 환원)되는데 소요되는 화학양론적인 당량으로 하였으며, 환원시험방법은 실제의 로타리킬른 조업조건을 고려한 것이다.The fixed carbon content of coke used above is 87.78% by weight, and the amount of coke added is 90% reduction of iron oxide and chromium oxide components in chromium ore (chromium oxide is Cr 2 O 3 to Cr 3 C 2) . The iron oxide is the stoichiometric equivalent of FeO to Fe), and the reduction test method takes into account the actual rotary kiln operating conditions.

상기 표2에 나타난 바와 같이, 기본 배합시의 금속화율에 비해 규석을 첨가하는 비교예(A, B)가 금속화율이 개선되었음을 알 수 있으며, 특히, 본 발명의 조성범위에 부합되게 사문암을 첨가한 발명재 E, F, G의 경우가 상기 비교예(A, B)에 비하여 더욱 향상된 금속화율을 나타내고 있다.As shown in Table 2, it can be seen that the comparative examples (A, B) to add silica compared to the metallization rate in the base compounding, the metallization rate is improved, in particular, adding serpentine rock in accordance with the composition range of the present invention In the case of the invention materials E, F and G, the metallization rate was further improved as compared with the comparative examples (A and B).

또한, 본 발명의 조성범위를 벗어나게 사문암을 첨가한 비교예 H는 오히려 감소되었다.In addition, Comparative Example H in which serpentine was added outside the composition range of the present invention was rather reduced.

상술한 바와 같이, 본 발명은 경제적으로 구입할 수 있는 사문암을 크롬광석 펠릿 원료에 첨가하므로서 보다 향상된 금속화율은 얻을 수 있는 효과가 있는 것이다.As described above, the present invention has an effect of obtaining an improved metallization rate by adding economically available serpentine to the chromium ore pellet raw material.

Claims (2)

예비환원 크롬광석 펠릿을 제조하기 위한 크롬광석 펠릿에 있어서, 크롬광석, 벤토나이트 및 코크스로 이루어진 크롬광석 펠릿 배합원료에 사문암이 3-7중량% 첨가되는 것을 특징으로 하는 고환원 크롬광석 펠릿.A chromium ore pellet for producing pre-reduced chromium ore pellets, wherein the serpentine is added to the chromium ore pellet blending material consisting of chromium ore, bentonite and coke, 3 to 7% by weight. 제1항에 있어서, 크롬광석이 88-94중량%, 벤토나이트가 3-5중량% 그리고 코크스가 크롬광석, 벤토나이트 및 사문암으로 이루어진 배합원료에 대하여 14-20중량%인 것을 특징으로 하는 고환원 크롬광석 펠릿.The high-reduced chromium according to claim 1, wherein the chromium ore is 88-94% by weight, bentonite is 3-5% by weight and the coke is 14-20% by weight based on the blended material consisting of chrome ore, bentonite and serpentine. Ore pellets.
KR1019880017833A 1988-12-29 1988-12-29 Pellet of high chrome ore KR910006014B1 (en)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101246331B1 (en) * 2010-11-19 2013-03-21 주식회사 포스코 APPARATUS FOR MANUFACTURING Fe-Cr
KR101246330B1 (en) * 2010-11-19 2013-03-21 주식회사 포스코 METHOD FOR MANUFACTURING Fe-Cr
KR101246332B1 (en) * 2010-11-19 2013-03-21 주식회사 포스코 COMPACTED CHROMIUM ORE AND FLUX FOR MANUFACTURING Fe-Cr
KR101492783B1 (en) * 2011-11-15 2015-02-12 오토텍 오와이제이 Process for the manufacture of ferrochrome
WO2017063250A1 (en) * 2015-10-14 2017-04-20 福建鼎信实业有限公司 Production method for hot-delivering oxidized pellets in shaft furnace to sealed ferrochrome electric furnace

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101246331B1 (en) * 2010-11-19 2013-03-21 주식회사 포스코 APPARATUS FOR MANUFACTURING Fe-Cr
KR101246330B1 (en) * 2010-11-19 2013-03-21 주식회사 포스코 METHOD FOR MANUFACTURING Fe-Cr
KR101246332B1 (en) * 2010-11-19 2013-03-21 주식회사 포스코 COMPACTED CHROMIUM ORE AND FLUX FOR MANUFACTURING Fe-Cr
KR101492783B1 (en) * 2011-11-15 2015-02-12 오토텍 오와이제이 Process for the manufacture of ferrochrome
WO2017063250A1 (en) * 2015-10-14 2017-04-20 福建鼎信实业有限公司 Production method for hot-delivering oxidized pellets in shaft furnace to sealed ferrochrome electric furnace

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