阅读说明：本技术 一种高钛渣除杂的方法 (Method for removing impurities from high-titanium slag ) 是由 赵林 金长浩 但勇 龙泽彬 高波 宋世杰 于 2020-06-22 设计创作，主要内容包括：本发明涉及一种高钛渣除杂的方法,包括以下步骤：步骤1、将粒度为0.02mm～0.1mm的高钛渣和硝酸溶液加入反应釜中,向反应釜中通入氧气,同时升温至130℃以上,然后搅拌条件下保温至少1h,降温,得到第一物料；其中,所述硝酸溶液的质量浓度为10%～30%；所述反应釜内的总压为0.5 Mpa～1.9 Mpa,所述反应釜中氧分压为0.25 MPa以上；搅拌转速为250r/min～800r/min；步骤2、将步骤1得到的第一物料进行过滤处理,得到过滤物和滤液,将过滤物进行水洗至洗液为中性,得到除杂后的高钛渣。发明人通过控制反应釜中氧分压、温度、保温时间、硝酸浓度、搅拌转速等多种因素的相互配合,使得除杂效果好,可以得到高纯度的高钛渣,且该方法能耗小、设备要求低。(The invention relates to a method for removing impurities from high-titanium slag, which comprises the following steps: step 1, adding high titanium slag with the granularity of 0.02 mm-0.1 mm and a nitric acid solution into a reaction kettle, introducing oxygen into the reaction kettle, simultaneously heating to above 130 ℃, then preserving heat for at least 1h under the stirring condition, and cooling to obtain a first material; wherein the mass concentration of the nitric acid solution is 10-30%; the total pressure in the reaction kettle is 0.5-1.9 Mpa, and the oxygen partial pressure in the reaction kettle is more than 0.25 Mpa; the stirring speed is 250r/min to 800 r/min; and 2, filtering the first material obtained in the step 1 to obtain a filtrate and a filtrate, and washing the filtrate with water until the washing liquid is neutral to obtain the high-titanium slag after impurity removal. The inventor controls the mutual cooperation of various factors such as oxygen partial pressure, temperature, heat preservation time, nitric acid concentration, stirring speed and the like in the reaction kettle, so that the impurity removal effect is good, high-purity high-titanium slag can be obtained, and the method has the advantages of low energy consumption and low equipment requirement.)

1. The method for removing impurities from high-titanium slag is characterized by comprising the following steps of:

step 1, adding high titanium slag with the granularity of 0.02 mm-0.1 mm and a nitric acid solution into a reaction kettle, introducing oxygen into the reaction kettle, simultaneously heating to above 130 ℃, then preserving heat for at least 1h under the stirring condition, and cooling to obtain a first material; wherein the mass concentration of the nitric acid solution is 10-30%; the total pressure in the reaction kettle is 0.5-1.9 Mpa, and the oxygen partial pressure in the reaction kettle is more than 0.25 Mpa; the stirring speed is 250r/min to 800 r/min;

and 2, filtering the first material obtained in the step 1 to obtain a filtrate and a filtrate, and washing the filtrate with water until the washing liquid is neutral to obtain the high-titanium slag after impurity removal.

2. An impurity removal method for high titanium slag according to claim 1, wherein in the step 1, the granularity of the high titanium slag is 0.02 mm-0.06 mm.

3. A method for removing impurities from high-titanium slag according to claim 1, wherein in the step 1, the mass ratio of the nitric acid solution to the high-titanium slag is 3-8: 1.

4. An impurity removal method for high titanium slag according to claim 1, wherein in the step 1, the stirring rotation speed is 400r/min to 600 r/min.

5. The method for removing impurities from high-titanium slag according to claim 1, wherein in the step 1, the temperature is increased to 130-200 ℃.

6. An impurity removal method for high titanium slag according to claim 1, wherein in the step 1, the oxygen partial pressure in the reaction kettle is 0.25MPa to 0.9 MPa.

7. The method for removing impurities from high-titanium slag according to claim 1, wherein TiO in the impurity-removed high-titanium slag obtained in the step 2 is₂The mass content is more than 90 percent.

8. The method for removing impurities from high titanium slag according to any one of claims 1 to 7, further comprising the step 3 of carrying out enrichment treatment on the filtrate obtained in the step 2, then carrying out evaporation crystallization, carrying out thermal decomposition treatment on the obtained crystal, and absorbing nitrogen oxides obtained by thermal decomposition by nitric acid absorption equipment to obtain a new nitric acid solution.

9. The method for removing impurities from high-titanium slag according to claim 8, wherein in the step 3, the specific steps of the heating decomposition treatment of the obtained crystal are as follows: and adding the obtained crystal into a heat accumulating type circulating decomposing furnace, contacting with circulating nitric oxide gas at 800-1100 ℃, decomposing for 1-3min, and decomposing to obtain oxide and nitric oxide gas.

10. A method for removing impurities from high-titanium slag according to claim 8, wherein the new nitric acid solution obtained in the step 3 is returned to the step 1 for recycling.

Technical Field

The invention belongs to the technical field of metallurgy, and particularly relates to a method for removing impurities from high-titanium slag.

Background

The high titanium slag is commonly known as titanium ore concentrate formed by a physical production process, and the titanium ore is heated and melted by an electric furnace, so that titanium dioxide and iron in the titanium ore are melted and separated to obtain the titanium dioxide concentrate with high content. The high titanium slag is neither waste slag nor by-product, but is a high-quality raw material for producing titanium tetrachloride, titanium white and titanium sponge products, and the titanium slag is smelted from titanium concentrate.

The chlorination process for preparing titanium dioxide has become the main method for producing titanium dioxide at present due to its advantages of short process, low production cost and energy consumption, and less pollution of three wastes, etc., TiO₂The high titanium slag with the content of more than 90 percent can be used as a production raw material of titanium white by a chlorination process, and is limited by the fact that titanium ores in China are generally low in taste and low in purity, particularly, impurities such as silicon, iron, manganese, calcium, magnesium and the like in the titanium slag are high in content and difficult to purify, and the industrial development of the titanium white and the titanium sponge in China is severely restricted.

At present, methods for removing impurities and improving quality of high-titanium slag include an electric heating method, a roasting pretreatment two-step leaching method, a hydrochloric acid leaching method, a sulfuric acid leaching method and an alkali leaching method; the electric heating method is a mature method, has simpler process, does not produce solid and liquid waste materials, belongs to high-temperature smelting, mainly removes sulfur, phosphorus and carbon, has higher energy consumption and generates a large amount of low-price titanium; the roasting pretreatment two-step leaching method comprises the steps of firstly carrying out sodium roasting to change the phase composition of titanium slag, and then selectively removing impurities in the titanium slag through hydrochloric acid pressure leaching, wherein the silicon removal effect is not obvious; the sulfuric acid method and the hydrochloric acid leaching method mainly aim at acid-soluble titanium slag, and have weak desiliconization capability, long reaction time and large investment on pressure leaching equipment; the alkali leaching method mainly comprises a new process for cleaning and metallurgy of sub-soluble salt titanium, which is proposed by the research on process engineering of Chinese academy of sciences, and the research proposes that high-titanium slag is used as a raw material, and a sodium-alkali molten salt method is adopted to prepare a titanium-rich material; the process comprises the steps of mixing titanium slag with sodium alkali, carrying out molten salt reaction on the titanium slag and the sodium alkali at normal pressure and low temperature, efficiently and selectively converting titanium in the titanium slag into titanate, carrying out hydrolysis and precipitation on the titanate, and leaving impurity components such as iron, calcium, magnesium and the like which do not react with the sodium alkali in a non-titanium slag phase to realize effective separation of Ti from other impurities, but the problems of excessive alkali consumption, high requirement on equipment, difficulty in later-stage separation and the like exist.

For example, in chinese patent 201510250414.4, the acid-soluble titanium slag is modified, subjected to acid impurity removal, and calcined by using microwaves as a heating method to meet the requirements of producing titanium white by a chlorination method, but the method requires a microwave reactor, and thus the investment on equipment is large; one or more modifiers selected from sodium carbonate, sodium hydroxide, phosphorus pentoxide, sodium phosphate or dihydrogen phosphate are added in the process of modifying the high-titanium slag, and various impurities are introduced, so that the subsequent quality improvement is difficult; the method uses sulfuric acid as pickle liquor, which causes difficulty in subsequent waste acid recovery and pollutes the environment; meanwhile, the calcination process needs to be heated to 900-1000 ℃ and has higher requirements on equipment and higher energy consumption; chinese patent 201510879416.X discloses a three-stage process for preparing high-quality titanium slag, which comprises the steps of modifying titanium slag, carrying out pressurized acid leaching and granulation, carrying out ball milling, roasting, filtering and washing, carrying out pressurized acid leaching, mixing with a binder uniformly, and carrying out microwave drying to obtain high-quality titanium slag; the process has complex operation procedures and higher equipment requirements, and other impurities can be introduced by adding the modifier to influence the upgrading process; chinese patent 201410387332.X discloses a method for preparing anatase titanium dioxide by acidolysis of clean titanium slag; the method comprises the steps of mixing and roasting common titanium slag serving as a raw material and sodium hydroxide, carrying out acidolysis by using sulfuric acid, hydrolyzing to obtain metatitanic acid precipitate, and roasting to obtain high-quality anatase titanium dioxide, wherein the process needs repeated roasting treatment to consume a large amount of energy, the acidolysis uses 15-55% sulfuric acid to seriously corrode equipment, and the subsequent waste acid is not well treated, so that the environmental hazard is large.

Disclosure of Invention

The invention aims to: aiming at the technical problems of high energy consumption, high equipment requirement, poor impurity removal effect and the like in the method for removing impurities from high-titanium slag in the prior art, the method for removing impurities from high-titanium slag is provided, and has the advantages of low energy consumption, low equipment requirement and good impurity removal effect.

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

a method for removing impurities from high-titanium slag comprises the following steps:

step 1, adding high titanium slag with the granularity of 0.02 mm-0.1 mm and a nitric acid solution into a reaction kettle, introducing oxygen into the reaction kettle, simultaneously heating to above 130 ℃, then preserving heat for at least 1h under the stirring condition, and cooling to obtain a first material; wherein the mass concentration of the nitric acid solution is 10-30%; the total pressure in the reaction kettle is 0.5-1.9 Mpa, and the oxygen partial pressure in the reaction kettle is more than 0.25 Mpa; the stirring speed is 250r/min to 800 r/min;

and 2, filtering the first material obtained in the step 1 to obtain a filtrate and a filtrate, and washing the filtrate with water until the washing liquid is neutral to obtain the high-titanium slag after impurity removal.

The invention provides a method for removing impurities from high-titanium slag. The method provided by the inventor has low requirement on equipment and low energy consumption, and the inventor controls the mutual cooperation of various factors such as oxygen partial pressure, temperature, heat preservation time, nitric acid concentration, stirring speed and the like in the reaction kettle, so that the impurity removal effect is good, and high-purity high-titanium slag can be obtained.

Further, step 1 is preceded by a step a: the high titanium slag is crushed to the granularity of 0.02 mm-0.1 mm.

Further, in the step 1, the granularity of the high titanium slag is 0.02 mm-0.06 mm. The inventor discovers that the granularity of the crushed high-titanium slag is an important parameter influencing the impurity removal rate through a large amount of researches, and discovers that the impurity removal effect is not good due to too small or too large granularity, and the high-titanium slag is likely to agglomerate due to too small granularity, so that the oxygen dispersion effect is influenced, and the purity of the final product is not obviously improved; if the granularity is too large, impurities can not be fully contacted with the nitric acid solution, the reaction is not sufficient, the final effect can be also affected adversely, and preferably, in the step 1, the high titanium slag is crushed to the granularity of 0.05-0.06 mm.

Further, in the step 1, the mass ratio of the nitric acid solution to the high titanium slag is 3-8: 1.

On the basis of controlling the mass concentration of the nitric acid solution to be 10-30%, the inventor researches and researches the mass ratio of the nitric acid solution to the high-titanium slag through experiments, wherein the poor impurity leaching effect is caused by the excessively small mass ratio of the nitric acid solution to the high-titanium slag, but the waste of the nitric acid solution is caused by the excessively large mass ratio, the economic burden is increased,

preferably, the mass ratio of the nitric acid solution to the high-titanium slag is 4.5-6: 1.

Further, in the step 1, the stirring speed is 400 r/min-600 r/min. Through a large amount of experimental researches and researches of the inventor, the stirring rotating speed in the reaction kettle has a direct and close relation to the purity of a final product, the rotating speed is too low, the dissolved oxygen in a reaction solution is possibly dispersed unevenly, high titanium slag is not dispersed unevenly, the reaction effect is poor, the rotating speed is too high, the contact between the high titanium slag and a nitric acid solution is possibly poor, the reaction is insufficient, and the poor impurity removal effect is also caused, preferably, in the step 1, the stirring rotating speed is 400 r/min-500 r/min.

Further, in the step 1, the temperature is raised to 130 ℃ to 200 ℃. The inventor discovers through research that when the temperature in the reaction kettle needs to be controlled to be higher than 130 ℃, and lower than 130 ℃, the reaction effect of the high titanium slag and the nitric acid in the reaction kettle is poor, and the purity of the final product is affected, but if the temperature is too high, the leaching effect is not greatly improved, and the economic burden is increased, and preferably, in the step 1, the temperature is increased to 130-200 ℃.

Further, in the step 1, heat preservation is carried out for 1-4 hours under the stirring condition. The inventor discovers through exploration that the setting of the heat preservation time in the reaction kettle is also important, when the heat preservation time is less than 1h, the high titanium slag and the nitric acid in the reaction kettle can not fully react, the purity of the final product is affected, but if the heat preservation time is too long, the leaching effect cannot be greatly improved, and the economic burden can be increased.

Further, in the step 1, the oxygen partial pressure in the reaction kettle is 0.25MPa to 0.9 MPa. The inventors have found through research that a factor of oxygen partial pressure in the reaction kettle is an important factor in the whole system, and when the oxygen partial pressure is lower than 0.25Mpa, the oxygen dispersion rate in the reaction kettle is low, which affects the leaching effect of impurities, but if the oxygen partial pressure is too high, the economic cost is also increased, and preferably, in the step 1, the oxygen partial pressure in the reaction kettle is 0.25Mpa to 0.5 Mpa.

Further, the TiO in the high titanium slag after impurity removal obtained in the step 2₂The mass content is more than 90 percent.

Further, the method also comprises a step 3 of carrying out enrichment treatment on the filtrate obtained in the step 2, then carrying out evaporative crystallization, carrying out heating decomposition treatment on the obtained crystal, and absorbing nitrogen oxides after thermal decomposition by nitric acid absorption equipment to obtain a new nitric acid solution.

Further, the method comprises a step 3 of carrying out enrichment treatment on the filtrate obtained in the step 2, evaporating and crystallizing, adding the obtained crystals into a heat storage type circulating decomposition furnace, contacting with circulating nitric oxide gas at 800-.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The percentage contents appearing in the following examples are not directly specified as percentages by mass.