Flotation and impurity reduction test of a high potassium sodium iron concentrate

With the increasing development of the modern steel industry, the grade of iron ore into the furnace of the increasingly high demand for iron ore impurity content requirements more demanding. In the presence of potassium and sodium in iron ore, potassium and sodium volatilize in the high temperature zone of the lower part of the blast furnace during iron making, and then oxidize into the charge in the upper part, and accumulate in the furnace, causing nodulation and reducing the strength of coke and ore ^{[1] ]} , while seriously affecting the service life of the blast furnace. An iron concentrate contains harmful impurities such as potassium and sodium, and the K+Na content is about 0.8%. A well-known German research institute started the ore dressing test from the original ore and failed to reduce the harmful impurities potassium and sodium to iron concentrate. Quality standard (0.3%). The Changsha Research Institute of Mining and Metallurgy has successfully tested the iron concentrate by reverse flotation by modifying and optimizing the collector .

First, the nature of the sample

The particle size of the ore sample is determined to be 90% - 0.075 mm. The results of multi-element chemical analysis of ore samples are shown in Table 1 ^[2] .

It was observed under the microscope: gangue minerals potassium feldspar and quartz majority, followed by biotite, chlorite, calcite, barite and the like. The feldspar is mostly granular, and the crystal grain size is mostly below 0.02 mm. The surface is generally slightly calcified and has a pale rose red color under the naked eye. The output form of quartz is relatively simple, often irregular granular, with particle sizes ranging from 0.02 to 0.1 mm. Iron minerals are basically dissociated, or partially present in poor organisms.

Second, laboratory test equipment and pharmacy

(1) The main equipments are XFD-63 series single-slot flotation machine; XFD-76 type trough-type flotation machine, standard sieve.

(2) The main reagents in the laboratory include HF regulator, etheramine, NaOH, CaO, SA regulator, SD inhibitor, AY-17 cation collector, and Hoss anion collector.

Third, flotation test and results

Reverse flotation is a mature iron-reducing process, which has been widely used in the concentrating plants of major steel companies at home and abroad. The main gangue in the iron concentrate is feldspar. The commonly used collectors for feldspar flotation are oleic acid and amines, and the regulators are hydrofluoric acid ^{[3 - 4]} .

(1) Drug screening test

The results of the reverse flotation test under different pharmaceutical systems are shown in Table 2. The flotation temperature of the cationic collector is normal temperature (20 ° C), and the flotation temperature of the anionic collector is 30 ° C.

It can be seen from Table 2 that the flotation of the AY-17 collector has the best effect, the flotation effect of the etheramine cation collector is second, and the Hoss anion collector has the worst effect. Taking into account the environmental impact of the agent, SA, SD and AY-17 were selected as the main flotation reagents for reverse flotation, and optimization experiments were carried out.

(2) SA adjusting agent dosage test

In order to examine the effect of SA on flotation indicators, the SA dosage test was conducted. The amount of fixed drug: SD dosage 133.3g / t, AY-17 dosage 100g / t. The test results are shown in Table 3.

It can be seen from Table 3 that when the amount of SA is zero, the impurity content of iron concentrate can meet the requirements; the addition of SA can greatly increase the yield of flotation foam, resulting in an increase in the grade of flotation foam, affecting iron. The recovery rate of the operation is not high, and the grade of iron concentrate is not increased much, and the drop of impurities is not large. Therefore, it is considered that no SA adjusting agent is added.

(3) SD inhibitor dosage test

SD is a commonly used effective iron inhibitor, widely used in the anti-flotation of iron concentrates, which can greatly improve the sorting efficiency of reverse flotation. In order to investigate the effect of SD dosage on flotation index, SD dosage test was carried out under the condition of AY-17 collector dosage of 66.7 g/t. The results are shown in Table 4.

It can be seen from Table 4 that with the increase of the amount of SD inhibitor, the concentrate yield and iron recovery rate increase, the potassium and sodium in the concentrate also increase, but all are within the qualified range, the foam grade is greatly reduced, and the concentrate is refined. The grade is slightly down.

(IV) AY-17 cation collector dosage test

The test results of the AY-17 collector dosage are shown in Table 5 under the condition that the SD dosage is 133.3 g/t.

It can be seen from Table 5 that as the amount of AY-17 increases, the grade of concentrate increases, the content of potassium and sodium of impurities decreases, the amount of collector only needs 66.7g/t, and the grade of iron concentrate reaches 69.93% of TFe. Potassium and sodium were reduced to 0.152% and were fully qualified.

(5) Flotation open circuit test

The amount of SD inhibitor was 133.3g/t, the amount of AY-17 collector was 66.7g/t, and the rough selection was carried out at 20 °C, and the open-circuit test was performed twice. The test results are shown in Table 6.

(6) Flotation closed circuit test

According to the results of the open circuit test, the qualified iron concentrate requirements can be obtained under the conditions of one roughing and two sweeping, and the iron recovery rate lost is also in a reasonable range. Taking into account the residual trapping agent in the closed loop foam, the amount of SD inhibitor is 200g/t, the amount of AY-17 collector is 66.7 g/t, the quality of 1 roughing and 2 sweeping closed loop test is shown in Figure 1. .

Fourth, the conclusion

(1) High-potassium and soda-iron concentrates (K+Na content of 0.8%) can achieve the effect of improving quality and reducing impurities by reverse flotation. The closed-circuit test has obtained 70.24% of iron concentrate grade, and impurity potassium in iron concentrate. The sodium content is 0.17%, which is below the 0.2% index.

(2) AY-17 can be used as an effective cationic collector for potassium and sodium.

references

Introduction [1] Li Hui, steel metallurgy [M]. Beijing: Metallurgical Industry Press, 1993.

[2] Luo Liangfei, a low-iron high-potassium iron ore iron test report [R]. Changsha: Changsha Research Institute of Mining and Metallurgy, 2009.

[3] Hu Weibai, flotation [M]. Beijing: Metallurgical Industry Press, 1992.

[4] Zhang Jian, Fan Liqin, Yan Wenhua, et al. Baotou Steel Concentrator Improves Quality and Reduces Miscellaneous Production Technology [C]∥ Metal Mine Magazine. In 2002, the national iron concentrates to improve quality and reduce the academic discussion and technical exchange meeting. Ma On Shan: Metal Mine Magazine, 2002: 126-130.

Features
1. Fluidizing drying, good heat transfer
2. Thanks to the enclosed structure of drying equipment, there is no need to worry about dust
3. The bag-type filter adopts antistatic fiber for safe operation