CN1046926C

CN1046926C - Method for recovering tailings of iron ore

Info

Publication number: CN1046926C
Application number: CN96109194A
Authority: CN
Inventors: 张伟晒
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-08-19
Filing date: 1996-08-19
Publication date: 1999-12-01
Anticipated expiration: 2016-08-19
Also published as: CN1148035A

Abstract

The present invention relates to a method for recovering tailings of iron ore. In the method, wet tailings of iron ore is calcined in a universal calcining device at the temperature of 400 DEG C to 800 DEG C, wherein the constant temperature is controlled between 400 DEG C and 600 DEG C for 30 minutes; then, ferroferric oxide slags are separated from an object to be calcined after carrying out magnetic separation by a universal magnetic separator, and can be recycled to be used as iron ore. The residues can be used as non-crystalline metakaolin mixed slags to be made into low-grade cement, tiles, or filler for mines, so the wet tailings which are originally seen as waste materials are recycled.

Description

Method for recovering iron ore tailing slag

The invention relates to a method for recovering iron ore tailings, in particular to a method for recovering wet iron ore tailings.

In the prior art, the tailings of the iron ore are divided into dry tailings and wet tailings, wherein the dry tailings can be used for building materials, and the wet tailings can be used as waste materials to be discharged and accumulated in a tailings field, so that the tailings not only occupy the land, but also have great harm to the environment. The search for a recovery method and a use thereof is one of the research contents of scientists today.

The invention aims to provide a method for recovering wet tailing slag in iron ore, namely a light-burning method. It can transform about half of wet tailings into a mineral material with iron content higher than 40% and reuse it as iron ore resource, and the other half of wet tailings can be transformed into active amorphous metakaolin, which can be used as mining filler or made into low grade cement, brick and other building materials or products.

The embodiments of the present invention are as follows: the recovery method of iron ore wet tailing slag (general grain size is less than 5 mm, iron content is more than 23%, water content is less than 50%), controlling proper calcination time from 400 deg.C to 800 deg.C, the calcination effect can be divided into three stages, stage 1: siderite (FeCO) contained in the tailing slag is treated at 400-600 deg.C₃) And hematite (Fe)₂O₃) The components are converted into magnetic ferroferric oxide, and the simple formula is as follows:

thus, the iron ore can be recovered by magnetic separation and reused as iron ore raw materials.

At this stage the following reaction was again carried out:

stage 1: kaolinite (Al) contained in tailing slag₂O₃·2SiO₂·2H₂O) to amorphous metakaolin (Al) with activity₂O₃·2SiO₂) It can be made into low-grade cement, brick and mine field filler. 。

Stage 2: at the temperature of 600-700 ℃, dolomite (CaMg) CO contained in the tailing slag is treated₃Converted into calcium oxide and magnesium oxide, also can be made into low-grade cement, brick and used as minesite filling material, etc., 。

stage 3: at 700-800 deg.C, adding calcite (CaCO) contained in the tailing slag₃) It can be used as calcium oxide, low-grade cement, brick, or filler in mine field. 。

And magnetite (Fe) originally contained in the tailings₂O₄) The iron ore is not changed and can be recovered by magnetic separation and reused as the iron ore raw material. In general, the ferriferrous oxide and the original tailings obtained in the first stage of calcinationThe magnetite inherent in the raw material is separated by magnetic separation to obtain the ferroferric oxide-containing mineral aggregate, the amount of which is about half of that of the untreated tailings, and the mixture containing amorphous metakaolin, calcium oxide, magnesium oxide and the like obtained in the other half, namely the 1 st stage, the 2 nd stage and the 3 rd stage can be prepared into low-grade cement, bricks and fillers.

The method of the invention has the advantages that:

1. the calcining method is simple, reliable and stable in process.

2. General calcination equipment may be used.

3. The wet tailing slag is utilized by 100 percent, the three wastes are completely recycled, and the environment can be greatly improved.

The following preferred examples describe the invention in detail, but are not meant to limit the scope of the invention.

Example 1: the wet tailings of meishan iron ore near Nanjing, when analyzed, generally contained the amount of each mineral within the following range (wt%) (about 50% of water had been evaporated).

Magnetite: 9-11 siderite: 15-17 kaolinite: 14-16

Calcite: 12-14 dolomite: 8-11 hematite: 4-6

Quartz: 14-16, and the balance of feldspar, pyrite, montmorillonite, clay and other components.

2 kg of wet tailing slag of the components are calcined in a crucible, when the temperature rise is from 400 ℃ to 600 ℃ for 30 minutes, the color of the tailing material is observed to be changed into grey brown, the constant temperature time from 400 ℃ to 600 ℃ is strictly controlled to be 20-45 minutes, the tailing material is changed into iron red, namely, the tailing material is calcined into iron redIncreasing the quantity proportion of ferroferric oxide in the Mingtai minerals, gradually increasing the temperature from 600 ℃ to 700 ℃ for 30 minutes, and finally stopping calcining when the temperature reaches 800 ℃. The specific magnetization coefficient value of the calcined tailing material is measured to be 5500 multiplied by 10^-6Mansion rice of C.G.S.M³Per gram. Magnetic separation is carried out by a general magnetic separator, the slag containing ferroferric oxide is separated to obtain 0.4 kg, and the slag can be used as the raw material of iron ore, and other amorphous metakaolin and calcium oxideAnd magnesium oxide, etc. in total, 0.58 kg. Can be made into low-grade cement, brick or used as mineral processing field filling material. Of course. During the calcination, less than 50% of the water contained has evaporated when the temperature reaches 100 ℃.

Example 2: the specific magnetization coefficient of the calcined material obtained by analysis was 6500X 10 under the same conditions as in example 1 except that the constant temperature time was changed to 20 minutes at 400-600 deg.C^-6Cm³And g, magnetically separating to obtain 0.35 kg of ferroferric oxide-containing slag and 0.62kg of amorphous metakaolin mixture.

Example 3: the specific magnetization coefficient of the calcined material obtained by analysis was 6800X 10 under the same conditions as in example 1 except that the calcination temperature was 400-600 ℃ and the constant temperature time was 45 minutes^-6Cm³And g, the slag containing ferroferric oxide obtained after magnetic separation is 0.32 kg, and the mixture of amorphous metakaolin is 0.54 kg.

From the above examples 1 to 3, it can be seen that when the calcination is carried out while the constant temperature of 400 ℃ and 600 ℃ is controlled for 30 minutes, the amount of ferroferric oxide contained in the calcined product is the highest.

Claims

1. A method for recovering iron ore tailing slag is characterized in that:

(1) calcining the wet iron ore tailings in a general calciner to calcine from 400 ℃ to 800 ℃ in stages, wherein the constant temperature time is controlled to be 20-45 minutes at the temperature of 400-600 ℃,

(2) and (3) magnetically separating the calcined substance in the step (1) to separate slag containing ferroferric oxide, wherein the residue is amorphous metakaolin mixed slag.

2. The recovery method of iron ore tailings according to claim 1, characterized in that: the calcination time is controlled to be 30 minutes when the calcination temperature is between 400 ℃ and 600 ℃.