Hematite-siderite-limonite mixed iron ore three-stage suspension roasting-magnetic separation method

A suspension roasting, iron ore technology, applied in chemical instruments and methods, magnetic separation, solid separation, etc., can solve the problems of long roasting time, waste of resources, poor sorting index, etc., to ensure the uniformity of reduction and efficient recovery The effect of improving the utilization and recovery rate

Inactive Publication Date: 2015-06-24
NORTHEASTERN UNIV
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Problems solved by technology

However, the ore size suitable for shaft furnace processing is 25~75mm. About 40% of the ore of 0~25mm in Jiuquan Iron and Steel Concentrator can only use the strong magnetic separation process, and only iron concentrate with a TFe grade of 49.06% can be obtained, and the iron recovery rate is 66.59% %, resulting in a large waste of resources
Moreover, the shaft furnace roasting process has problems such as high energy consumption, long roasting time, and uneven product quality.
Changsha Research Institute of Mining and Metallurgy conducted a systematic coal-based rotary kiln magnetization roasting-weak magnetic separation-reverse flotation test study on Daxigou siderite, and built a Daxigou concentrator with an annual processing capacity of 1.8 million tons based on this. The iron concentrate TFe grade is 60.63%, and the iron recovery rate is 75.42%. However, the rotary kiln process still has problems such as low magnetic susceptibility, easy ring formation, unstable production, low operating rate and high energy consumption.
[0005] When the above magnetization roasting technology is used to process hematite-siderite-limonite mixed ore, there are the following three problems: 1. Due to the inconsistency of iron mineral properties, the reactions of different minerals under the same reduction conditions are not synchronized, and the reduction materials cannot complete reaction to form magnetic Fe 3 o 4 , or there is over-reduction to generate non-magnetic FeO, which leads to poor sorting indicators; 2. The heating and reduction of materials are carried out simultaneously, and the reduction atmosphere is difficult to guarantee, and it is difficult to implement industrialization; 3. It cannot handle 0~25mm fine-grained materials

Method used

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  • Hematite-siderite-limonite mixed iron ore three-stage suspension roasting-magnetic separation method
  • Hematite-siderite-limonite mixed iron ore three-stage suspension roasting-magnetic separation method
  • Hematite-siderite-limonite mixed iron ore three-stage suspension roasting-magnetic separation method

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Experimental program
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Effect test

Embodiment 1

[0051] The main components of the red chestnut-brown mixed iron ore used are shown in Table 1 (unit wt%);

[0052] Table 1

[0053] components TF FeO SiO 2 Al 2 o 3 CaO content 34.43 9.24 49.41 0.15 0.39 components MgO P S K Na content 0.37 0.07 0.05 0.04 0.03

[0054] The chemical phase analysis results are shown in Table 2;

[0055] Table 2

[0056]

[0057] The method proceeds as follows:

[0058] 1. Pre-oxidation: Grind the red chestnut-brown mixed iron ore until the particle size -0.074mm accounts for 40% of the total weight, then put it into the suspension reaction furnace, and feed air into the suspension reaction furnace to make the material suspended state; the material in the suspension reaction furnace is heated to 800°C for pre-oxidation roasting. At this time, the suspension reaction furnace is an oxidizing atmosphere, and the pre-oxidation time is 10s; Iron ore-limonite mixed ore;

[0059] 2. Hea...

Embodiment 2

[0065] The iron grade of red chestnut brown mixed iron ore is 33%, and it contains 21% FeO, SiO 2 30%;

[0066] Method is with embodiment 1, and difference is:

[0067] (1) The part that is ground to a particle size of -0.074mm accounts for 50% of the total weight, and is heated to 700°C for pre-oxidation roasting, and the pre-oxidation time is 30s;

[0068] (2) The reduction time is 10 seconds; the flow ratio of CO and nitrogen is 1:3;

[0069] (3) When the temperature drops to 350°C, air is introduced into the suspension reaction furnace for reoxidation; the main component of the reoxidized material is magnetic iron γ-Fe 2 o 3 and Fe 3 o 4 ; where γ-Fe 2 o 3 The weight content is 60%, Fe 3 o 4 The weight content is 36%;

[0070] (4) After secondary grinding, when the part of the material with a particle size of -0.044mm accounts for 50% of the total weight, magnetic separation is carried out under the condition of a magnetic field strength of 60~100kA / m; the reco...

Embodiment 3

[0072] The iron grade of red chestnut mixed iron ore is 30%, and it contains 9% FeO, SiO 2 40%;

[0073] Method is with embodiment 1, and difference is:

[0074] (1) The part that is ground to a particle size of -0.074mm accounts for 60% of the total weight, and is heated to 600°C for pre-oxidation roasting, and the pre-oxidation time is 60s;

[0075] (2) The reduction time is 30 seconds; the flow ratio of CO and nitrogen is 1:5;

[0076] (3) When the temperature drops to 300°C, air is introduced into the suspension reaction furnace for reoxidation; the main component of the reoxidized material is magnetic iron γ-Fe 2 o 3 and Fe 3 o 4 ; where γ-Fe 2 o 3 The weight content is 70%, Fe 3 o 4 The weight content is 22%;

[0077] (4) When the material after the secondary grinding to the particle size -0.044mm accounts for 60% of the total weight, magnetic separation is carried out under the condition of a magnetic field strength of 60~100kA / m; the recovery rate of iron i...

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Abstract

The invention discloses a hematite-siderite-limonite mixed iron ore three-stage suspension roasting-magnetic separation method and belongs to the technical field of mineral processing. The method comprises the following steps: (1) performing ore grinding on the hematite-siderite-limonite mixed iron ore, putting in a suspension reacting furnace till the materials are in a suspending state; heating to the temperature of 450-800 DEG C and performing preoxidized roasting; (2) stopping heating, and introducing nitrogen to replace the air; introducing a reducing gas till the materials are in a suspension loose state and performing reduction; (3) replacing the unreacted residual reducing gas, introducing the air to reoxidize when the temperature is reduced to 250-400 DEG C and taking out to perform secondary ore grinding; and (4) performing magnetic separation when the magnetic field intensity is 60-100 kA / m. The method provided by the invention is simple in process, strong in method adaptability, safe and reliable in process, uniform and stable in product quality and energy-saving and energy-reducing, and the recovery rate of the high refractory ore is increased.

Description

technical field [0001] The invention belongs to the technical field of mineral processing, and in particular relates to a three-stage suspension roasting-magnetic separation method of red chestnut-brown mixed iron ore. Background technique [0002] With the rapid development of my country's iron and steel industry, the demand for iron ore has risen sharply; my country's iron ore has low grade, poor endowment, and high mining and dressing costs, resulting in domestic iron ore production far from meeting the needs of the development of the iron and steel industry; in 2014, my country imported There are 933 million tons of iron ore, and the dependence on foreign countries is as high as 78.5%. The high dependence of iron ore on foreign countries further reduces the international discourse power and safety of China Iron and Steel. In 2014, the price of imported iron ore has dropped from US$130 / t at the beginning of the year to below US$70 / t, and the price of domestic iron ore has ...

Claims

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Application Information

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IPC IPC(8): C22B1/02B03C1/00
Inventor 李艳军韩跃新高鹏
Owner NORTHEASTERN UNIV
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