Preparation Of Iron Powder Research Articles

Preparation of iron powders using rotary cup atomizer with water curtain

A novel atomization process based on a rotary cup atomizer (RCA) was proposed to manufacture iron powders using semisteel as the raw material. To achieve rapid cooling of iron droplets and efficient separation of iron powders from cooling water, a circle of water curtain was set around the RCA in the experimental setup. The effects of rotating speed, cup diameter, slope angle, and cup depth on the particle size of iron granules were investigated to meet the size requirement of iron powders applied as reductive agent during the sulfate process. Results indicated that the optimal conditions for the atomization of semisteel were a rotating speed of 1800 rpm, a cup diameter of 150 mm. Under such conditions, the accumulative fraction of the obtained iron granules that measured less than 0.45 mm reached a maximum of 93.12 wt% when the slope angle and cup depth were 45° and 50 mm. Thus, this novel preparation process for iron powders with semisteel using RCA basically achieved the required particle size. The median diameter of the obtained iron granules decreased with an increase in rotating speed, cup diameter, slope angle, and cup depth. The disintegration mechanism of semisteel was determined, and the result indicated that the atomization process probably followed the ligament formation mode. A modified correlation that considered the influences of slope angle and cup depth was proposed to predict median granule size. An analysis on atomizer design was conducted based on these findings to provide a good insight for industrialization. As with RCA design for the treatment of molten semisteel rating up to 3.5 t/h, the minimum diameter of the rotary cup decreased from 1.36 m to 1.10 m as the rotary speed increased from 1200 rpm to 1800 rpm.

Study on Preparation of Iron Powder and Nano-Carbon Black by Reaction Process of High-Iron Bauxite and Natural Gas

In this paper, high-iron bauxite was reduced deeply using natural gas as reductant in a closed circulation reduction furnace and then it was disposed by ball milling and magnetic separation. The results of study showed: when the optimum conditions of reduction of high-iron bauxite were that a temperature of 900°C, a reaction time of 120 min and a material thickness of 5 mm, iron powder and carbon black can be obtained, the particle size of iron powder was about 50∼200 nm, and the carbon black was about 30∼100 nm.

The preparation of iron powders consisting of submicroscopic elongated particles by pseudomorphic reduction of iron oxides

The preparation of submicroscopic elongated iron particles by pseudomorphic reduction of α-FeOOH with hydrogen has been studied. At a temperature of 350°C rapid sintering occurs of the iron particles formed. At temperatures below 300°C sintering is largely absent but the reaction is too slow. It has been found that the reduction rate at low temperatures can be increased, and hence sintering diminished, by absorption of Ag+ or Co+ ions on the surface of the iron oxide particles, leading to iron powders with improved magnetic properties. When Sn2+is adsorbed the reaction rate decreases. Yet the coercivity of the iron powders obtained is considerably increased, probably also due to a diminished sintering.

Fatigue strength of sintered iron-base antifriction materials

1. Sintered antifriction materials based on iron powder lose much of their strength when subjected to cyclic loading. 2. Increasing the porosity of these materials substantially lowers both their static and fatigue strengths. It should be noted in this connection that the dependence of the static strength on porosity is similar in character to the dependence of the fatigue strength on porosity. 3. Increasing the amount of free graphite also adversely affects the strength characteristics, but, at a porosity of 20% or more, graphite-content variation has but little effect on the static and fatigue strengths. Additions of copper and sulfur raise the strength of the materials investigated. 4. The number of cycles to the inflexion point on the fatigue curve diminishes with increasing porosity. The scatter of fatigue-test results generally increases with increasing porosity. 5. The method of preparation of iron powder affects the strength characteristics of the materials.

Carbide-thermic method of preparation of iron powder

The author has developed a process for the preparation of high-purity iron powder, which is based on the reduction of mill scale or rich iron ore with calcium carbide and subsequent concentration of the reaction products by magnetic wet separation.

Combined process for the reduction of iron scale in continuous vertical muffle furnaces

A description is given of an improved technique for the preparation of iron powder from scale. As a result of the investigation, the quality of the powder has been raised, its cost reduced, and the working conditions have been improved.

Preparation of iron powder by the thermal decomposition of iron pentacarbonyl

1. A new method is proposed for the preparation of electronic iron powders by the thermal decomposition of liquid iron pentacarbonyl atomized by means of centrifugal nozzles. 2. A technological process has been developed for the production of powders by the new method. Powder has been produced in the form of two fractions—a fine one from the filter (20%) and a coarser one from the decomposition apparatus (80%). The fine fraction consists mainly of particles 0.5–1.0 μ in size. 3. The electromagnetic parameters of both fractions meet present-day electronic industry requirements.