阅读说明：本技术 一种高硫磁铁矿精矿脱硫的酸预处理-浮选方法 (Acid pretreatment-flotation method for high-sulfur magnetite concentrate desulfurization ) 是由 冯泉 张强 于 2020-07-02 设计创作，主要内容包括：本发明的一种高硫磁铁矿精矿脱硫的酸预处理-浮选方法,该工艺在处理铁精矿脱硫过程中,首先将高硫磁铁矿精矿配成浓度矿浆后,进行特定程度的酸预处理,再经浓缩过滤进行固液分离,滤液返回酸预处理工序,预处理铁精矿选用黄药捕收剂进行脱硫浮选,得到合格铁精矿和硫尾矿。该工艺酸预处理中的酸液可循环使用,降低药剂成本,脱硫浮选过程无需添加活化剂,药剂制度和流程结构简单。通过酸预处理-浮选工艺可获得硫含量低、铁回收率高的铁精矿,有效解决磁黄铁矿与磁铁矿的分离难题。(The invention relates to an acid pretreatment-flotation method for high-sulfur magnetite concentrate desulfurization, which is characterized in that in the process of treating iron concentrate desulfurization, firstly, high-sulfur magnetite concentrate is prepared into concentrated ore pulp, then acid pretreatment is carried out to a specific degree, solid-liquid separation is carried out through concentration and filtration, filtrate returns to the acid pretreatment process, and the pretreated iron concentrate is subjected to desulfurization flotation by using a xanthate collecting agent to obtain qualified iron concentrate and sulfur tailings. The acid liquor in the acid pretreatment of the process can be recycled, the cost of the reagent is reduced, an activating agent is not required to be added in the desulfurization flotation process, and the reagent system and the flow structure are simple. The iron ore concentrate with low sulfur content and high iron recovery rate can be obtained by an acid pretreatment-flotation process, and the separation problem of pyrrhotite and magnetite is effectively solved.)

1. An acid pretreatment-flotation method for high-sulfur magnetite concentrate desulfurization is characterized by comprising the following steps:

(1) taking high-sulfur magnetite concentrate to prepare ore pulp with the concentration of 30-50 wt%, adding sulfuric acid to adjust the initial pH value of the ore pulp to 1.0-2.0, and carrying out pretreatment under the stirring condition for 20-80 min to obtain pretreated ore pulp;

(2) concentrating and filtering the pretreated ore pulp, and performing solid-liquid separation to obtain acid liquor and pretreated iron ore concentrate;

(3) the method comprises the steps of preparing desulfurization flotation ore pulp with the concentration of 30-35 wt% by acid pretreatment of iron ore concentrate, adjusting the pH value, adding a collecting agent and a foaming agent, wherein the adding amount of the collecting agent is 100-600 g/t, the adding amount of the foaming agent is 20-90 g/t, carrying out open-circuit desulfurization flotation, and obtaining a foam product which is sulfur tailings, and an iron ore concentrate in a cell, wherein the open-circuit desulfurization flotation comprises 1-time roughing and 1-2-time concentrating.

2. The acid pretreatment-flotation method for desulfurizing the high-sulfur magnetite concentrate according to claim 1, wherein in the step (1), the TFe grade of the high-sulfur magnetite concentrate is 63.43-65.86%, and the S content is 1.31-4.57%; the high-sulfur magnetite concentrate comprises pyrrhotite and pyrite, wherein the pyrrhotite and the pyrite form sulfur-containing minerals, the content of the pyrrhotite in the high-sulfur magnetite concentrate is 3.35-11.70%, and the fineness of the high-sulfur magnetite concentrate is-0.074 mm and accounts for more than 90%.

3. The acid pretreatment-flotation method for desulfurizing the high-sulfur magnetite concentrate according to claim 1, wherein in the step (1), the stirring speed is 200-600 rpm, and the pretreatment temperature is room temperature.

4. The acid pretreatment-flotation method for desulfurization of high-sulfur magnetite concentrate according to claim 1, wherein in the step (3), the desulfurization flotation pulp is subjected to flotation after adjusting the pH to 5.0-5.5, and the pH adjustment is completed by adding an alkaline regulator.

5. The acid pretreatment-flotation method for desulfurization of high-sulfur magnetite concentrate according to claim 4, wherein in the step (2), the alkalinity regulator is selected from one of sodium hydroxide, sodium carbonate or potassium hydroxide.

6. The acid pretreatment-flotation method for desulfurizing the high-sulfur magnetite concentrate according to claim 1, wherein in the step (3), the collector is butyl xanthate or amyl xanthate, and the foaming agent is 2# oil.

7. The acid pretreatment-flotation method for desulfurizing the high-sulfur magnetite concentrate according to claim 1, wherein in the step (3), the addition amount of the collecting agent in 1-time roughing is 300-600 g/t, the addition amount of the foaming agent is 50-90 g/t, the addition amount of the collecting agent in 1-time concentrating is 200-400 g/t, the addition amount of the foaming agent is 25-45 g/t, the addition amount of the collecting agent in 2-time concentrating is 100-200 g/t, and the addition amount of the foaming agent is 20-30 g/t.

8. The acid pretreatment-flotation method for desulfurization of high-sulfur magnetite concentrate according to claim 1, wherein in the step (3), the yield of iron concentrate is 75.68-89.24%, the S content is 0.12-0.25%, and the TFe recovery rate is 78.43-96.02%.

The technical field is as follows:

the invention belongs to the technical field of mineral flotation separation and resource comprehensive utilization in the field of mineral processing engineering, and particularly relates to an acid pretreatment-flotation process for iron ore concentrate desulfurization, in particular to a process method for flotation separation of magnetite and pyrrhotite.

Background art:

iron ore resources are rich in China, and the reserves of iron ore are in the forefront of the world. Iron ore resources in China are widely distributed but relatively concentrated, and various types of iron ore deposits with different sizes are found in regions such as northeast, southwest, eastern China, southwest and northwest China, but the iron ore resources in China are mainly poor ores (accounting for 98 percent of the total reserves), are difficult to develop and high in production cost, so that the dependence of the iron and steel industry in China on iron ore import exceeds 50 percent.In addition, the quality of domestic iron ore concentrate is poor, and the main problem of the iron ore concentrate is that the iron ore concentrate contains SiO₂、S、Al₂O₃And the like.

Sulfur, a common impurity in iron ore, directly causes the quality of steel to deteriorate. Most of iron ores in Shanxi, Hubei, Anhui, Yunnan, Xinjiang and other places in China contain pyrite, pyrrhotite, chalcopyrite and other metal sulfide minerals. In order to fully utilize the iron ore resources, iron ore concentrate desulfurization treatment is required. The pyrite and the magnetite have large magnetic difference and can be effectively removed through ore grinding-magnetic separation; however, as the magnetism of the pyrrhotite is similar to that of the magnetite, the pyrrhotite and the magnetite can enter magnetite concentrate together and are difficult to remove, and the pyrrhotite in different crystal systems and production areas has large property difference and is easy to oxidize in air, so that no mature ore dressing process can effectively realize the separation of the pyrrhotite and the magnetite at home and abroad.

The sulfur in magnetite concentrate that is difficult to remove effectively is mainly pyrrhotite. At present, the iron ore concentrate desulfurization process comprises the following steps: magnetic separation process, leaching process, oxidizing roasting, microbial desulfurization and flotation process. Although partial research is carried out on the leaching process, the oxidizing roasting process and the microbial desulfurization process, the industrial application effect of magnetite concentrate desulfurization (pyrrhotite) is poor. At present, flotation technology is mostly adopted at home and abroad to carry out magnetite concentrate desulfurization, and the gravity center of flotation desulfurization research is mainly in the aspects of an activating agent and a collecting agent, and the emerging novel activating agent and the high-efficiency combined collecting agent play a good desulfurization effect to a certain extent. However, when magnetite concentrate contains refractory pyrrhotite with poor flotability or high oxidation degree, the novel reagent cannot fundamentally solve the problem of magnetite concentrate desulfurization. Therefore, it is very urgent to find a treatment method capable of effectively removing the sulfur-containing minerals in the magnetite concentrate.

The invention content is as follows:

the invention aims to overcome the defects of the prior flotation and desulfurization of the sulfur-containing iron ore concentrate which is difficult to treat in the prior art, and provides the iron ore concentrate desulfurization process which has simple flow structure and medicament system, low beneficiation cost and good stability and can effectively realize the sulfur-containing pyrrhotite.

According to the technical scheme, an acid pretreatment process is added before the desulfurization flotation operation, the surface activity of sulfur-containing minerals which are difficult to float is improved under the action of acid pretreatment of the sulfur-containing iron ore concentrate, and the sulfur-containing minerals in the iron ore concentrate can be effectively removed through the desulfurization flotation operation, so that the iron ore concentrate which is low in sulfur content and meets the quality requirement is obtained. The process solves the problem of effective desulfurization of the sulfur-containing iron ore concentrate with poor floatability and high oxidation degree.

In order to achieve the purpose, the invention adopts the following technical scheme:

an acid pretreatment-flotation method for high-sulfur magnetite concentrate desulfurization comprises the following steps:

(1) taking high-sulfur magnetite concentrate to prepare ore pulp with the concentration of 30-50 wt%, adding sulfuric acid to adjust the initial pH value of the ore pulp to 1.0-2.0, and carrying out pretreatment under the stirring condition for 20-80 min to obtain pretreated ore pulp;

(2) concentrating and filtering the pretreated ore pulp, and performing solid-liquid separation to obtain acid liquor and pretreated iron ore concentrate;

(3) the method comprises the steps of preparing desulfurization flotation ore pulp with the concentration of 30-35 wt% by using iron ore concentrate subjected to acid pretreatment, adjusting the pH value, adding a collecting agent and a foaming agent, wherein the adding amount of the collecting agent is 100-600 g/t, and the adding amount of the foaming agent is 20-90 g/t, performing open-circuit desulfurization flotation to obtain a foam product which is sulfur tailings, and obtaining an iron ore concentrate in a cell, wherein the open-circuit desulfurization flotation comprises 1-time roughing and 1-2-time concentrating.

In the step (1), the TFe grade of the high-sulfur magnetite concentrate is 63.43-65.86%, and the S content is 1.31-4.57%; the high-sulfur magnetite concentrate comprises a large amount of pyrrhotite and a small amount of pyrite, the pyrrhotite and the pyrite form sulfur-containing minerals, the content of the pyrrhotite in the high-sulfur magnetite concentrate is 3.35-11.70%, and the fineness of the high-sulfur magnetite concentrate is-0.074 mm and accounts for more than 90%.

In the step (1), the concentration of the ore pulp is 30-50 wt%, the ore pulp is too high in concentration and difficult to effectively activate the surface of the sulfur-containing mineral, the acid dosage is increased due to too low concentration, and the medicament cost is increased.

In the step (1), the initial pH value of the ore pulp is 1.0-2.0, and the pH value of the ore pulp directly influences the pretreatment effect of sulfur-containing minerals in the iron ore concentrate.

In the step (1), the stirring speed is 200-600 rpm, and the pretreatment temperature is room temperature; the operation is preferably carried out at the rotating speed of 600rpm, which is beneficial to the dispersion of ore pulp and the contact action of sulfuric acid, shortens the pretreatment time and improves the efficiency.

In the step (2), a concentration magnetic separator and a ceramic filter can be adopted for solid-liquid separation, and the obtained acid liquid can be recycled, so that the method is economic and environment-friendly.

In the step (3), the desulfurization flotation pulp is floated after the pH value is adjusted to 5.0-5.5, and the pH adjustment is completed by adding an alkaline regulator.

In the step (3), the alkalinity regulator is selected from one of sodium hydroxide, sodium carbonate or potassium hydroxide.

In the step (3), the open-circuit process can reduce the adverse effect caused by middling return.

In the step (3), the collecting agent is butyl xanthate or amyl xanthate.

In the step (3), the foaming agent is 2# oil.

In the step (3), the addition amount of the collecting agent for 1-time rough concentration is 300-600 g/t, the addition amount of the foaming agent is 50-90 g/t, the addition amount of the collecting agent for 1-time fine concentration is 200-400 g/t, the addition amount of the foaming agent is 25-45 g/t, the addition amount of the collecting agent for 2-time fine concentration is 100-200 g/t, and the addition amount of the foaming agent is 20-30 g/t.

In the step (3), the yield of the obtained iron ore concentrate is 75.68-89.24%, the S content is 0.12-0.25%, and the recovery rate of TFe is 78.43-96.02%.

The invention has the beneficial effects that:

1. the sulfur-containing magnetite concentrate is subjected to desulfurization flotation after acid pretreatment, any activating agent is not needed, only a conventional metal sulfide collecting agent and a foaming agent are needed to be added, and the flotation agent system is simple;

2. according to the magnetite concentrate desulfurization acid pretreatment-flotation process, the desulfurization flotation is a coarse 1-2 fine concentration open-circuit process, and the process structure is simple;

3. the acid liquid obtained by the acid pretreatment and solid-liquid separation can be recycled, so that the cost of the medicament is saved, and the method is economical and feasible;

4. compared with the conventional flotation operation, the acid pretreatment-flotation process has the advantages of obvious desulfurization effect, strong adaptability and small yield loss of iron ore concentrate.

Description of the drawings:

FIG. 1 is a process flow diagram of an acid pretreatment-flotation process for desulfurization of high sulfur magnetite concentrate of examples 1-4 of the present invention.

The specific implementation mode is as follows:

the present invention will be described in further detail with reference to examples.

An acid pretreatment-flotation method for high-sulfur magnetite concentrate desulfurization comprises the following steps:

(1) taking high-sulfur magnetite concentrate, wherein the TFe grade of the high-sulfur magnetite concentrate is 63.43-65.86%, the S content is 1.31-4.57%, the high-sulfur magnetite concentrate comprises a large amount of pyrrhotite and a small amount of pyrite, the pyrrhotite and the pyrite form sulfur-containing minerals, the pyrrhotite content in the high-sulfur magnetite concentrate is 3.35-11.70%, the fineness of the high-sulfur magnetite concentrate is-0.074 mm and accounts for more than 90%, preparing the high-sulfur magnetite concentrate into ore pulp with the concentration of 30-50 wt%, adding sulfuric acid to adjust the initial pH value of the ore pulp to be 1.0-2.0, stirring at 200-600 rpm, carrying out pretreatment at room temperature, wherein the pretreatment time is 20-80 min, and obtaining the pretreated ore pulp, preferably, wherein the rotation speed is 600 rpm;

(2) concentrating and filtering the pretreated ore pulp, and performing solid-liquid separation by adopting a concentration magnetic separator and a ceramic filter to obtain acid liquor and pretreated iron ore concentrate, wherein the acid liquor can be recycled;

(3) preparing iron ore concentrate from acid pretreatment into desulfurization flotation pulp with the concentration of 30-35 wt%, adding an alkaline regulator (specifically one of sodium hydroxide, sodium carbonate or potassium hydroxide), adjusting the pH to 5.0-5.5, adding a collecting agent and a foaming agent, wherein the collecting agent is butyl xanthate or amyl xanthate, the adding amount is 100-600 g/t, the foaming agent is 2# oil, the adding amount is 20-90 g/t, performing open-circuit desulfurization flotation to obtain a foam product which is sulfur tailings, and the product in a tank is iron ore concentrate, so that the yield of the iron ore concentrate is 75.68-89.24%, the S content is 0.12-0.25%, and the recovery rate of TFe is 78.43-96.02%; the open-circuit desulfurization flotation comprises 1 time of roughing and 1-2 times of concentrating, wherein the adding amount of a collecting agent of the 1 time of roughing is 300-600 g/t, the adding amount of a foaming agent is 50-90 g/t, the adding amount of a collecting agent of the 1 time of concentrating is 200-400 g/t, the adding amount of the foaming agent is 25-45 g/t, the adding amount of a collecting agent of the 2 times of concentrating is 100-200 g/t, and the adding amount of the foaming agent is 20-30 g/t.