阅读说明：本技术 提高钛渣酸解率的方法 (Method for improving acidolysis rate of titanium slag ) 是由 李凯茂 肖军 宋兵 于 2020-05-18 设计创作，主要内容包括：本发明属于钛渣生产技术领域,具体涉及一种提高钛渣酸解率的方法。针对目前采用钛渣制备硫酸法钛白时,钛渣酸解率低的问题,本发明提供了一种提高钛渣酸解率的方法,包括以下步骤：a、将钛精矿和还原剂配料冶炼,按加料及功率输送匹配值为0.8MWh/t～1.2MWh/t,精炼时间为0～1h,得到TiO<Sub>2</Sub>60％～80％钛渣；b、对出炉钛渣进行缓冷冷却；c、将钛渣和硫酸预混,加热进行酸解反应,引发温度为150℃～190℃,主反应时间为8～15min,熟化温度为155～185℃,熟化时间2～3h,再经还原、浸出、沉降、过滤,分别得到钛液和残渣。本发明通过对钛渣物相组成进行精确控制,改变黑钛石相和硅酸盐相包裹形式,使得钛渣酸解率可稳定在95％以上,取得了显著的进步。(The invention belongs to the technical field of titanium slag production, and particularly relates to a method for improving the acidolysis rate of titanium slag. Aiming at the problem that the acidolysis rate of titanium slag is low when titanium white is prepared by a sulfuric acid process by adopting the titanium slag at present, the invention provides a method for improving the acidolysis rate of the titanium slag, which comprises the following steps: a. smelting the titanium concentrate and a reducing agent, wherein the matching value of charging and power transmission is 0.8 MWh/t-1.2 MWh/t, and the refining time is 0-1 h to obtain TiO 2 60 to 80 percent of titanium slag; b. slowly cooling the discharged titanium slag; c. premixing titanium slag and sulfuric acid, heating for acidolysis reaction at an initiation temperature of 150-190 ℃, for a main reaction time of 8-15 min, at a curing temperature of 155-185 ℃, for a curing time of 2-3 h, and then carrying out reduction, leaching, settling and filtering to obtain a titanium liquid and residues respectively. The invention changes the wrapping form of the black titanium phase and the silicate phase by accurately controlling the phase composition of the titanium slag, so that the acidolysis rate of the titanium slag can be stabilized to be more than 95 percent, and the remarkable progress is obtained.)

1. The method for improving the acidolysis rate of the titanium slag is characterized by comprising the following steps of:

a. titanium slag smelting

Selecting TiO₂40-50% of titanium concentrate and reducing agent with fixed carbon more than 80% and reactivity of 50-70%, mixing the titanium concentrate and the reducing agent according to the ratio of 100: 7-15, and adding the mixture into an electric furnace for reduction smelting; the TiO is obtained by the smelting process according to the matching value of charging and power transmission of 0.8 MWh/t-1.2 MWh/t and the refining time of 0-1 h₂60 to 80 percent of titanium slag;

b. titanium slag cooling

Slowly cooling the discharged titanium slag to obtain titanium slag with a grade of 60-80%, a black titanium stone content of more than 90%, a rutile content of less than 1% and a low-valence titanium oxidation rate of less than 0.5%;

c. acidolysis of titanium slag

And premixing the cooled titanium slag and sulfuric acid according to the acid slag ratio of 1.55-1.75, heating for acidolysis reaction at the initiation temperature of 150-190 ℃, the main reaction time of 8-15 min, the curing temperature of 155-185 ℃, the curing time of 2-3 h, and then reducing, leaching, settling and filtering to respectively obtain titanium liquid and residues.

2. The method for improving the acidolysis rate of titanium slag according to claim 1, wherein the acidolysis rate of titanium slag is as follows: step a the reactivity was tested using a PL-500F coke reactivity unit.

3. The method for improving the acidolysis rate of titanium slag according to claim 1, wherein the acidolysis rate of titanium slag is as follows: and c, slowly cooling the steel plate in the step b at the initial temperature of 1620-1720 ℃ and the final temperature of below 300 ℃.

4. The method for improving the acidolysis rate of titanium slag according to claim 1, wherein the acidolysis rate of titanium slag is as follows: and c, the cooling time of the slow cooling of the titanium slag in the step b is 15-24 h every 8-15 t.

5. The method for improving the acidolysis rate of titanium slag according to claim 1, wherein the acidolysis rate of titanium slag is as follows: the concentration of the sulfuric acid in the step c is 85-95%.

6. The method for improving the acidolysis rate of titanium slag according to claim 1, wherein the acidolysis rate of titanium slag is as follows: and when the grade of the cooled titanium slag is 60-70%, the concentration of sulfuric acid in the step c is 85-90%, the acid slag ratio is 1.55-1.65, the initiation temperature is 150-170 ℃, the main reaction time is 10-15 min, the curing temperature is 155-175 ℃, and the curing time is 2-3 h.

7. The method for improving the acidolysis rate of titanium slag according to claim 1, wherein the acidolysis rate of titanium slag is as follows: and when the grade of the cooled titanium slag is 70-80%, the concentration of sulfuric acid in the step c is 90-95%, the acid slag ratio is 1.65-1.75, the initiation temperature is 170-190 ℃, the main reaction time is 8-13 min, the curing temperature is 175-185 ℃, and the curing time is 2-3 h.

Technical Field

The invention belongs to the technical field of titanium slag production, and particularly relates to a method for improving the acidolysis rate of titanium slag.

Background

Ilmenite and titanium slag are the main raw materials of sulfate process titanium dioxide. Compared with ilmenite, the titanium slag has obvious advantages in the aspects of increasing the productivity of unit equipment, shortening the process flow, reducing the ferrous sulfate as a titanium white byproduct in a sulfuric acid method and the like. With the improvement of the national requirement on environmental protection, the survival pressure of titanium dioxide factories in the sulfuric acid process is getting bigger and bigger, especially in Panzhihua areas, several existing titanium dioxide production enterprises are forced to stop production or select titanium slag as a production raw material due to the treatment problem of ferrous sulfate, and the environmental protection problem becomes the biggest problem restricting the development of the titanium dioxide enterprises in the sulfuric acid process. Therefore, the acid-soluble titanium slag used as a raw material tends to develop the titanium white by the sulfuric acid method.

However, the acidolysis rate of the titanium slag is lower than that of ilmenite by 4-5%, and the improvement of the acidolysis rate of the titanium slag is the main research direction of technicians in the field at present. Factors influencing the acidolysis rate of the titanium slag are closely related to the composition of the titanium slag phase, and the typical titanium slag phase mainly comprises titanium black stone, silicate, rutile, a small amount of metallic iron and the like. The phase composition of the titanium slag is easily affected by the cooling mode. Researches indicate that a quenching mode is not beneficial to the formation and growth of a titanium black stone phase, and the titanium black stone phase of the titanium slag is reduced possibly to reduce the acidolysis rate of the titanium slag; the temperature of the titanium slag is more than 750 ℃ in the cooling process, and rutile TiO which is difficult to dissolve in sulfuric acid is easily formed by oxidizing the titanium slag₂Rutile type TiO in titanium slag₂The higher the content, the lower the acidolysis rate.

Besides the great influence of the cooling mode on the phase of the titanium slag, the phase composition of the titanium slag has a great relationship with the control of the smelting process, but relevant documents for the research on the aspect are only reported.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: when the titanium slag is used for preparing the titanium white by the sulfuric acid process, the acidolysis rate of the titanium slag is low.

The technical scheme for solving the technical problems comprises the following steps: the method for improving the acidolysis rate of the titanium slag comprises the following steps:

a. titanium slag smelting

Selecting TiO₂40-50% of titanium concentrate and reducing agent with fixed carbon more than 80% and reactivity of 50-70%, mixing the titanium concentrate and the reducing agent according to the ratio of 100: 7-15, and adding the mixture into an electric furnace for reduction smelting; the TiO is obtained by the smelting process according to the matching value of charging and power transmission of 0.8 MWh/t-1.2 MWh/t and the refining time of 0-1 h₂60 to 80 percent of titanium slag;

b. titanium slag cooling

Slowly cooling the discharged titanium slag to obtain titanium slag with a grade of 60-80%, a black titanium stone content of more than 90%, a rutile content of less than 1% and a low-valence titanium oxidation rate of less than 0.5%;

c. acidolysis of titanium slag

And premixing the cooled titanium slag and sulfuric acid according to the acid slag ratio of 1.55-1.75, heating for acidolysis reaction at the initiation temperature of 150-190 ℃, the main reaction time of 8-15 min, the curing temperature of 155-185 ℃, the curing time of 2-3 h, and then reducing, leaching, settling and filtering to respectively obtain titanium liquid and residues.

In the method for improving the acidolysis rate of the titanium slag, the reactivity in the step a is tested by a PL-500F coke reactivity device.

In the method for improving the acidolysis rate of the titanium slag, the slow cooling initial temperature in the step b is 1620-1720 ℃, and the final temperature is below 300 ℃.

In the method for improving the acidolysis rate of the titanium slag, the cooling time of the slow cooling of the titanium slag in the step b is 15-24 h per 8-15 t.

Wherein, in the method for improving the acidolysis rate of the titanium slag, the concentration of the sulfuric acid in the step c is 85-95%.

In the method for improving the acidolysis rate of the titanium slag, when the grade of the cooled titanium slag is 60-70%, the concentration of sulfuric acid in the step c is 85-90%, the acid slag ratio is 1.55-1.65, the initiation temperature is 150-170 ℃, the main reaction time is 10-15 min, the curing temperature is 155-175 ℃, and the curing time is 2-3 h.

In the method for improving the acidolysis rate of the titanium slag, when the grade of the cooled titanium slag is 70-80%, the concentration of sulfuric acid in the step c is 90-95%, the acid slag ratio is 1.65-1.75, the initiation temperature is 170-190 ℃, the main reaction time is 8-13 min, the curing temperature is 175-185 ℃, and the curing time is 2-3 h.

Compared with the prior art, the invention has the beneficial effects that:

the invention provides a method for improving the acidolysis rate of titanium slag, which changes the wrapping form of a titanium black stone phase and a silicate phase by accurately controlling the phase composition of the titanium slag, and controls key parameters in the acidolysis of the titanium slag by slowly cooling the titanium slag. The method has strong operability and important practical significance.

Detailed Description

The invention provides a method for improving the acidolysis rate of titanium slag, which comprises the following steps:

a. titanium slag smelting

Selecting TiO₂40-50% of titanium concentrate and reducing agent with fixed carbon more than 80% and reactivity of 50-70%, mixing the titanium concentrate and the reducing agent according to the ratio of 100: 7-15, and adding the mixture into an electric furnace for reduction smelting; the TiO is obtained by the smelting process according to the matching value of charging and power transmission of 0.8 MWh/t-1.2 MWh/t and the refining time of 0-1 h₂60 to 80 percent of titanium slag;

b. titanium slag cooling

Slowly cooling the discharged titanium slag to obtain titanium slag with a grade of 60-80%, a black titanium stone content of more than 90%, a rutile content of less than 1% and a low-valence titanium oxidation rate of less than 0.5%;

c. acidolysis of titanium slag

And premixing the cooled titanium slag and sulfuric acid according to the acid slag ratio of 1.55-1.75, heating for acidolysis reaction at the initiation temperature of 150-190 ℃, the main reaction time of 8-15 min, the curing temperature of 155-185 ℃, the curing time of 2-3 h, and then reducing, leaching, settling and filtering to respectively obtain titanium liquid and residues.

In the method for improving the acidolysis rate of the titanium slag, the reactivity in the step a is tested by a PL-500F coke reactivity device.

In the method for improving the acidolysis rate of the titanium slag, the slow cooling initial temperature in the step b is 1620-1720 ℃, and the final temperature is below 300 ℃.

In the method for improving the acidolysis rate of the titanium slag, the cooling speed cannot be too high for sufficiently and slowly cooling, and the cooling time of the slowly cooling titanium slag in the step b is 15-24 h per 8-15 t.

Wherein, in the method for improving the acidolysis rate of the titanium slag, the concentration of the sulfuric acid in the step c is 85-95%.

In the method for improving the acidolysis rate of the titanium slag, when the grade of the cooled titanium slag is 60-70%, the concentration of sulfuric acid in the step c is 85-90%, the acid slag ratio is 1.55-1.65, the initiation temperature is 150-170 ℃, the main reaction time is 10-15 min, the curing temperature is 155-175 ℃, and the curing time is 2-3 h.

In the method for improving the acidolysis rate of the titanium slag, when the grade of the cooled titanium slag is 70-80%, the concentration of sulfuric acid in the step c is 90-95%, the acid slag ratio is 1.65-1.75, the initiation temperature is 170-190 ℃, the main reaction time is 8-13 min, the curing temperature is 175-185 ℃, and the curing time is 2-3 h.

The main improvement of the invention is that: the phase composition of the titanium slag is changed by batching, and the phase composition of the titanium slag is related to the separation and sedimentation time of slag iron. The separation of slag iron is poor, the settling time is short, the black titanium stone phase and the silicate phase are poor in separation, and the acidolysis rate of the titanium slag is slower, so that the complete acidolysis reaction is influenced. The slag iron separation is related to the matching value of charging and power transmission, and the settling time is related to the refining time. The feeding amount is higher than the theoretical power conveying amount, the refining time is short, the slag iron separation is poor, the feeding amount is lower than the theoretical power conveying amount, the refining time is long, the power consumption is high, the smelting time is long, and the smelting cost is influenced. And refining time and feed and power delivery match values are related to the reactivity of the selected reductant. The lower the feed and power delivery match values and the shorter the refining time, the more reactive the selected reducing agent and, conversely, the less reactive the reducing agent. Therefore, in order to comprehensively balance the cost and the slag-iron separation and sedimentation time, the invention particularly sets the matching value of charging and power transmission in the smelting process to be 0.8 MWh/t-1.2 MWh/t, sets the refining time to be 0-1 h, and can adjust the acidolysis rate of the titanium slag by adjusting the phase composition.

Meanwhile, the invention adopts a slow cooling mode, the cooling mode is favorable for the nucleation and growth of the black titanium phase, the requirement on the internal temperature of the slag block is met when the slag block is crushed, the rutile content and the low-valence titanium content in the titanium slag are mainly controlled, the phase composition is further controlled, and the acidolysis rate of the titanium slag is favorably improved.

The control of key parameters of titanium slag acidolysis is of great importance to the acidolysis rate. The black titanium stone phase in the titanium slag phase comprises an iron-containing high black titanium stone phase and an iron-containing low black titanium stone phase. The two contents are different, and the key parameters of acidolysis are different. The content difference of the two is mainly related to the reduction depth in the titanium slag smelting process. The deeper the titanium slag is smelted and reduced, the higher the titanium slag grade is, and the higher the iron-containing low-blacktitanium ore phase ratio is. Conversely, the lower the proportion of iron-containing low-titanium-black phase. The key parameters of acidolysis mainly comprise indexes such as reaction acid concentration, acid-slag ratio, initiation temperature, main reaction time, curing temperature, curing time and the like. The invention screens out different reaction conditions by tests aiming at the titanium slag with the grade of 60-70 percent and the titanium slag with the grade of 70-80 percent respectively, thereby further improving the acidolysis rate of the titanium slag.

The following examples are intended to illustrate specific embodiments of the present invention without limiting the scope of the invention to the examples.