CN101380678A

CN101380678A - Technological process for producing reduced iron fine-powder

Info

Publication number: CN101380678A
Application number: CNA2007100127943A
Authority: CN
Inventors: 高振华; 张志华
Original assignee: BEIPIAO SHENGLONG POWDER METALLURGY Co Ltd
Current assignee: Beipiao Xinzheng Powder Metallurgy Co. Ltd.
Priority date: 2007-09-08
Filing date: 2007-09-08
Publication date: 2009-03-11
Anticipated expiration: 2027-09-08
Also published as: CN101380678B

Abstract

The invention discloses a technique for producing reduced iron concentrate powder. In the technique, decomposition ammonia gas is pumped into the iron powder reduced by one time in a reducing furnace at the temperature of 750 to 900 DEG C for reducing the iron powder into the iron concentrate powder. The method is technically characterized in that water vapor and chlorine hydride gas are pumped simultaneously when the decomposition ammonia gas is pumped; the pumped flux of the ammonia gas is 40 to 60m<3>/h; the controlled flux of the water vapor and the chlorine hydride gas are 5 to 10m<3>/h; the mixed volume ratio of the water vapor to the chlorine hydride gas is 1: 0.1 to 0.2. As the water vapor and the chlorine hydride gas are added into the reduced gas, the dew point of the decomposition ammonia gas is controlled within a certain range, thus being capable of reducing the carbon content of an iron concentrate product from the original content of more than 0.4 percent to a content below 0.02 percent; the technical flow is reasonable; the production cost is lower; the product quality is greatly improved.

Description

Produce the process of reduced iron fine-powder

Technical field

The present invention relates to a kind of production method of reduced iron powder, particularly the production technology of secondary reduction iron powder.

Background technology

At present domestic in the production process of producing reduced iron powder, part sponge iron phosphorus content through once reduction is higher, producing the smart powder of iron need be through secondary reduction, to be reduced into purity be iron essence powder more than 99.0% through decomposing ammonia to be about to a reduced iron powder 98.5% or more, but the smart powder phosphorus content of the iron that the common process that once reduces obtains is higher, usually phosphorus content reaches more than 0.4%, can not satisfy the specification requirement of the smart powder of high standard iron to carbon content, the direct rolled-up stock of the smart powder of iron can be owing to high processing and the serviceability that influences product of phosphorus content thus.

Summary of the invention

The objective of the invention is to overcome the defective that exists in the existing secondary reduction iron refined powder producing process is that phosphorus content is higher than technical standard, provides a kind of decarburization effect remarkable, the reduced iron fine-powder production technology that properties of product improve greatly.

To achieve these goals, the present invention feeds to decompose in the secondary reduction reaction and quantitatively adds water vapour and hydrogen chloride gas in the ammonia process, make the dew point of cracked ammonium be controlled at certain limit, the inventive method is the iron powder through once reduction to be fed the decomposition ammonia make the smart powder of iron in 750～900 ℃ of reduction in reduction furnace, it is characterized in that feeding water vapour and hydrogen chloride gas simultaneously at feeding cracked ammonium gas, the feeding flow of cracked ammonium gas is 40～60m ³/ hour, water vapour and hydrogen chloride gas control flow are 5～10m ³/ hour, water vapour is 1:0.1～0.2 with the mixed volume ratio of hydrogen chloride gas.

The used cracked ammonium of the present invention is that liquid ammonia is through being decomposed into 75%H ₂+ 25%N ₂Mist mixes with water vapour hydrogen chloride in the feeding secondary reduction stove through purifying, and water vapour control temperature is 120～150 ℃, and the dew point of cracked ammonium gas is controlled at-30～-50 ℃, and the reduction reaction time is 3～6 hours.

Technology of the present invention compared with prior art has following advantage:

1, owing to increased water vapour and hydrogen chloride gas in the reducing gases, control cracked ammonium gas dew point is in certain limit, and the phosphorus content that can make the smart powder product of iron is by original being reduced to more than 0.4% below 0.02%;

2, technological process is reasonable, and production cost is lower, has improved product quality greatly.

The specific embodiment

Embodiment 1:

Be in 98.5% the smart powder reduction furnace of reduced iron powder input steel band type iron, then reduction furnace to be heated content, when being warming up to 800～850 ℃, feeding and decompose ammonia (liquid ammonia becomes 75%H through pyrolysis ₂+ 25%N ₂Mist), import iron powder and reducing gas continuously under this reduction temperature, ammonia flow is controlled at 45～50m ³/ hour, and feeding water vapour and hydrogen chloride gas simultaneously, flow is 5～7m ³/ hour, water vapour is 1:0.1～0.2 with the mixed volume ratio of hydrogen chloride gas, steam temperature is 120～150 ℃, decompose the ammonia dew point and be controlled at-30～-50 ℃, reach 3～4 hours when the reduction reaction time, continue promptly to obtain finished product 850 ℃～900 ℃ insulations 1～2 hour.

Embodiment 2:

Be in 98.0% the smart powder reduction furnace of reduced iron powder input steel band type iron, then reduction furnace to be heated content, when being warming up to 800～850 ℃, feeding and decompose ammonia (liquid ammonia becomes 75%H through pyrolysis ₂+ 25%N ₂Mist), import iron powder and reducing gas continuously under this reduction temperature, ammonia flow is controlled at 45～50m ³/ hour, and feeding water vapour and hydrogen chloride gas simultaneously, flow is 8～10m ³/ hour, water vapour is 1:0.1～0.2 with the mixed volume ratio of hydrogen chloride gas, steam temperature is 120～150 ℃, decompose the ammonia dew point and be controlled at-30～-40 ℃, reach 3～4 hours when the reduction reaction time, continue promptly to obtain finished product 850 ℃～900 ℃ insulations 1～2 hour.

Examination and test of products the results list is as follows: (wt% of unit)

Claims

1, a kind of process of producing reduced iron fine-powder, be in reduction furnace, to feed the decomposition ammonia to make the smart powder of iron through the iron powder of once reduction in 750～900 ℃ of reduction, it is characterized in that feeding water vapour and hydrogen chloride gas simultaneously at feeding cracked ammonium gas, the feeding flow of cracked ammonium gas is 40～60m ³/ hour, water vapour and hydrogen chloride gas control flow are 5～10m ³/ hour, water vapour is 1:0.1～0.2 with the mixed volume ratio of hydrogen chloride gas.

2,, it is characterized in that the dew point of cracked ammonium gas is controlled at-30～-50 ℃ according to the process of the described production reduced iron fine-powder of claim 1.

3, according to the process of the described production reduced iron fine-powder of claim 1, it is characterized in that steam temperature is 120～150 ℃, reduction reaction temperature is 800～850 ℃, the reduction reaction time is 3～6 hours.