4 Siderite beneficiation process

Siderite is a common carbonate mineral with relatively low iron content, usually in granular, earthy, or dense massive aggregates. As a common weak magnetic iron ore, siderite is difficult to beneficiate. At present, there are four kinds of siderite beneficiation methods: siderite gravity separation, siderite strong magnetic separation, siderite flotation, magnetized roasting-weak magnetic separation.

1. Siderite gravity separation process

The gravity separation process is suitable for the treatment of coarse-grained and medium-grained siderites, and heavy-medium beneficiation and jig beneficiation are often used.

Dense medium beneficiation mainly uses dense and easy-to-regenerate solid (such as ferrosilicon, magnetite, galena) fine particles mixed with water to form a resuspension with adjustable density as the separation medium. The density of ore particles with a density greater than that of the medium sinks, The ore particles whose density is lower than the medium float up, so as to realize the separation.

The gravity separation process has large production capacity, low investment, high separation accuracy according to specific gravity, and strong adaptability to the particle size of the selected ore.

Jig beneficiation is based on the density difference of ore. The ore mixture is separated into a vertically elevated, variable-speed media stream.

The jig has the characteristics of simple structure, low investment, high separation efficiency and high recovery rate. Under suitable conditions, about 80% of the waste rock in siderite can be removed.

2. Siderite Intensive Magnetic Separation Process

After crushing, screening, grinding and grading, the siderite to be selected is sent to the washing tank and the desliming tank for desliming treatment, and repeatedly enters the washing tank and the desliming tank for many times to obtain the deslimed siderite. After desliming, the siderite is sent to a wet-type strong magnetic separator for separation, and outputs high-grade magnetic concentrate powder, low-grade magnetic tailings powder and medium-grade magnetic medium mineral powder in three ways.

3. Siderite flotation process

The flotation process is mainly used for the separation of fine siderite, including two processes: positive flotation and reverse flotation.

The positive flotation process is to grind the siderite to the desired particle size and then desliming. After desliming, the fatty acid collector is added to the neutral or weakly acidic medium to flotate iron minerals (also known as acid positive flotation).

In addition, it is not necessary to de-slime after grinding, just add soda and other regulators, use oxidized paraffin soap and tall oil as collectors, and flotation in weak alkaline medium (also known as alkaline positive flotation process).

4. Siderite magnetization roasting-weak magnetic separation process

Siderite is a carbonate of iron. After roasting in a neutral or weakly reducing atmosphere, the carbon dioxide in the ore is decomposed, thereby improving the grade of the ore. The magnetic properties of iron minerals are obviously enhanced, while the magnetic properties of gangue minerals have little change, and can be sorted by weak magnetic separation.

Commonly used magnetization roasting methods mainly include reduction roasting, neutral roasting and oxidative roasting.

Among them, reduction roasting method is widely used, namely shaft furnace (75-15mm) and rotary kiln (15-0mm), roasting temperature is controlled at 650-900 ℃, roasting time is as long as 6-8 hours, and as short as 15-10 minute.

Through this beneficiation process, siderite can be converted into magnetite, and then separated by a weak magnetic field magnetic separator to obtain a higher-grade concentrate.