阅读说明：本技术 硫酸亚铁与硫化钡制硫酸钡与硫化亚铁工艺 (Process for preparing barium sulfate and ferrous sulfide from ferrous sulfate and barium sulfide ) 是由 陈朝华 于 2018-07-02 设计创作，主要内容包括：本发明是将BaS液与Na<Sub>2</Sub>SO<Sub>4</Sub>液起反应,制得BaSO<Sub>4</Sub>沉淀,过滤得Na<Sub>2</Sub>S滤液。如：BaS+Na<Sub>2</Sub>SO<Sub>4</Sub>＝BaSO<Sub>4</Sub>↓+Na<Sub>2</Sub>S。继续将Na<Sub>2</Sub>S液与FeSO<Sub>4</Sub>液起反应制得FeS沉淀,过滤得Na<Sub>2</Sub>SO<Sub>4</Sub>滤液。如：Na<Sub>2</Sub>S+FeSO<Sub>4</Sub>＝FeS↓+Na<Sub>2</Sub>SO<Sub>4</Sub>。这Na<Sub>2</Sub>SO<Sub>4</Sub>液可返还上式作原料,重复循环使用。在整个反应过程中Na<Sup>+</Sup>离子从Na<Sub>2</Sub>SO<Sub>4</Sub>变成Na<Sub>2</Sub>S,再后又变成Na<Sub>2</Sub>SO<Sub>4</Sub>。只是起初加入Na<Sub>2</Sub>SO<Sub>4</Sub>,往后Na<Sub>2</Sub>SO<Sub>4</Sub>和Na<Sub>2</Sub>S都是重复循环使用。这就是生产中Na<Sub>2</Sub>SO<Sub>4</Sub>和Na<Sub>2</Sub>S这两种原料不必购买,节约了原料成本,提高了经济效益。其他原料也不贵,使成品的造价很低。而硫酸钡每吨近三千元。欲办一个年产五千吨硫酸钡厂,每年可得产值一千多万元,利润空间很大。是一个设备简、投资少、工艺短、上马易、见效快、用途广、成本低、效益好的短平快项目。(The invention is to mix BaS liquid with Na 2 SO 4 Reacting the solution to obtain BaSO 4 Precipitating, filtering to obtain Na 2 And (5) filtering the solution S. Such as: BaS + Na 2 SO 4 ＝BaSO 4 ↓+Na 2 And S. Continuing to add Na 2 S liquid and FeSO 4 Reacting the solution to obtain FeS precipitate, and filtering to obtain Na 2 SO 4 And (6) filtering the solution. Such as: na (Na) 2 S+FeSO 4 ＝FeS↓+Na 2 SO 4 . This Na 2 SO 4 The liquid can be returned to the above formula as raw material for repeated recycling. Na in the whole reaction process + Ion from Na 2 SO 4 To Na 2 S, then becomes Na 2 SO 4 . Only Na is initially added 2 SO 4 In the future, Na 2 SO 4 And Na 2 And S is repeatedly recycled. This is Na in production 2 SO 4 And Na 2 S is not necessary to purchaseThe raw material cost is saved and the economic benefit is improved. Other raw materials are not expensive, so that the cost of the finished product is low. And barium sulfate is nearly three thousand yuan per ton. A factory producing five thousand tons of barium sulfate every year is expected to obtain more than one thousand yuan per year, and the profit margin is large. The method is a short and flat project with simple equipment, less investment, short process, easy application, quick effect, wide application, low cost and good benefit.)

1. The process for preparing barium sulfate and ferrous sulfide from ferrous sulfate and barium sulfide is characterized by comprising the following steps of:

(1) preparing barium sulfide clear liquid: 1) mixing barite and anthracite in a weight ratio of 100: 23-30, crushing, conveying to a rotary furnace, and roasting at 1000-1200 ℃ for 1-2 hours in a counter-current manner to obtain a yellow melt; 2) feeding the yellow melt into a spiral leacher, and leaching by hot water in a countercurrent manner, wherein the leaching temperature is controlled at 70 ℃, and the concentration of barium sulfide in the spiral leacher is controlled at 200 g/L, so as to obtain a barium sulfide solution; 3) putting the barium sulfide solution into a clarifier, standing and clarifying to obtain barium sulfide clarified liquid; the content of barium sulfate in the barite is more than 85%, and the content of fixed carbon in the anthracite is more than 70%;

(2) preparing barium sulfate: 1) dissolving mirabilite with sodium sulfate content higher than 85% with water of 50 deg.C, heating to 90 deg.C, stopping adding mirabilite when the concentration of mirabilite solution reaches 26 ° Be, heating mirabilite solution with steam, removing magnesium and calcium from mirabilite solution, clarifying for more than 20 hr to obtain settled mud and clear sodium sulfate solution, and feeding the clear sodium sulfate solution into a metering tank for use; 2) mixing the barium sulfide clarified liquid in the step (1) with a sodium sulfate clear liquid, heating to 80 ℃, carrying out double decomposition reaction to generate white barium sulfate precipitate, continuously adding the sodium sulfate clear liquid, and finishing the reaction when the white barium sulfate precipitate is not increased any more; 3) carrying out solid-liquid separation to obtain white barium sulfate precipitate and clear liquid containing sodium sulfide, washing the white barium sulfate precipitate with water, carrying out diluted acid washing, washing with water, drying and crushing to obtain the barium sulfate;

(3) preparing ferrous sulfide: 1) FeSO (ferric oxide) is added₄·7H₂Dissolving O in water, and then adding the clear liquid containing sodium sulfide in the step (2) under the condition of heating until the 2-valent iron ions are completely precipitated; 2) heating to boil for half an hour, and standing for 1 hour; 3) and (3) carrying out solid-liquid separation to obtain ferrous sulfide solid and sodium sulfate clear liquid, washing and drying the ferrous sulfide solid to obtain the ferrous sulfide, and returning the sodium sulfate clear liquid to the step (2) for preparing barium sulfate to realize the reuse of the sodium sulfate.

2. The process of claim 1, wherein the rotary furnace in step (1) has a length of 25 m to 45 m, a diameter of 1.5 m to 2.5 m, an inclination angle of 2 ° to 6 °, and a rotation speed of 1 rpm to 5 rpm, and is lined with clay refractory bricks.

3. The process for preparing barium sulfate and ferrous sulfide from ferrous sulfate and barium sulfide as claimed in claim 1, wherein the content of silica in barite in step (1) is not higher than 3%.

4. The process of claim 1, wherein the chemicals used in step (2) to remove magnesium and calcium from the mirabilite solution are lime and soda ash.

The technical field is as follows:

the invention relates to effective utilization of ferrous sulfate as a byproduct in a titanium dioxide factory. Belongs to the technical field of chemical waste utilization.

Technical background:

ferrous sulfate is a by-product separated out from titanium liquid by freezing crystallization in the production of titanium dioxide plants. The application of the ferrous sulfate is wide at present. In the book "titanium dioxide production and application technology" published by the chemical publishing company of China, pages 523 to 538, which is written by the inventor, the application details of ferrous sulfate are provided, and the details are not repeated herein.

Although the application range of ferrous sulfate is very wide, the annual dosage is also very large, the yield of titanium dioxide in China is too large, and one ton of titanium dioxide can produce three tons of iron polysulfate simultaneously. In 2017, the yield of titanium dioxide in China is 287 ten thousand tons, wherein at least 800 million tons of ferrous sulfate is produced nationwide except that more than ten thousand tons of titanium dioxide are produced by a chlorination method and no ferrous sulfate is produced; the national titanium dioxide yield in 2016 is 260 ten thousand tons, and simultaneously, the yield of ferrous sulfate is over 800 ten thousand tons.

Over the years, the production of ferrous sulphate is certainly too great. So that the ferrous sulfate is seriously excessive for a long time. Since the product is rare and expensive, most of the product is base, and the ferrous sulfate is too much, the product becomes very base. Guangxi has a titanium dioxide factory, and ferrous sulfate produced in a certain period of time is transported to Liuzhou by a train and sold to an iron oxide red factory, but due to the low price, the price is more than that of ferrous sulfate in addition to the train transportation cost, the short-distance transportation cost of two automobiles and the loading and unloading cost, so that the cost is reduced. Thus, the product is not sold and is freely transported by anyone. In this way, the ferrous sulfate produced cannot be treated completely. And then have to be disposed of as a waste stack or landfill. However, ferrous sulfate is a strong acid and weak base salt, is easily dissolved in water, and the aqueous solution is acidic and reductive. When a large amount of ferrous sulfate is leached by rainwater, the produced water permeates into farmlands or rivers and causes pollution to a certain degree. If the water flows into the farmland, the soil is acidified, and the yield is reduced; when the water flows into a river, the reductive ferrous sulfate consumes oxygen in the water, so that aquatic organisms such as fishes in the water cannot obtain enough oxygen and die by suffocation. Thus destroying the aquatic resources and the ecological balance in water.

Because the yield of the ferrous sulfate is excessive for a long time, more application fields of the ferrous sulfate must be expanded to solve the problem of the excessive yield of the ferrous sulfate. And certain economic benefits can be obtained from such resource utilization. This is a difficult task in front of titanium dioxide workers. And the titanium dioxide powder produced by the sulfuric acid method can be continuously developed only by solving the problem of the ferrous sulfate going out.

In 1997, the inventor accepts the principal and commission entrustment of Luchuan county to be responsible for the design, construction, equipment installation, debugging and compiling of engineering projects of 3000t/a lithopone, and teaches himself. The result is successful in one production. The yield and the quality meet the requirements, and the products are sold all over the country and exported to Korea 6 wagons. The project is identified by superior technology. And a book of lithopone, 23 ten thousand characters, was written in 2000, and was published by the chemical publishing company of China. The lithopone is a white pigment which is prepared by carrying out decomposition reaction on a zinc sulfate solution and a barium sulfide solution to produce two precipitates of barium sulfate and zinc sulfide with equal mol. Wherein the reaction equation is as follows:

ZnSo₄+BaS＝BaSO₄↓+ZnS↓

later, I took the post of the general engineer of Guangxi Luchuan titanium dioxide works of joint ventures in China. See that the amount of ferrous sulfate is so much that the treatment is difficult, and whether the ferrous sulfate can replace zinc sulfate to react with barium sulfide to produce barium sulfate and ferrous sulfide like lithopone has been thought to be produced or not? Namely, it is

Although two precipitates were also available, this precipitate had a black FeS, which was not feasible. Later, I have studied all the time, and the result is that a two-step method is adopted, and two types of precipitates are obtained and are separated for precipitation. In the first step, sodium sulfate is firstly reacted with barium sulfide to prepare white barium sulfate precipitate. The reaction equation is as follows:

the second step is to use the Na produced in the first step₂S, precipitating with ferrous sulfate. The reaction equation is as follows:

after the FeS was removed by filtration, the sodium sulfate produced was pumped to the first step and used repeatedly as a raw material.

Knot made in this wayFruit, Na⁺The two reactions are both in the system, and can be circularly used for a long time. Therefore, two raw materials, namely sodium sulfate and sodium sulfide, are not required to be added in the production, and the cost of a large amount of raw materials can be reduced. And FeSO₄SO in (1)₄ ²⁺And Fe²⁺Barium sulfate precipitate and ferrous sulfide precipitate are obtained in the first step and the second step respectively. Thereby allowing the two precipitates to separate. The inventor thinks that the method can not only consume a certain amount of ferrous sulfate, thereby properly reducing the burden of serious surplus of the ferrous sulfate yield, but also can obtain better economic benefit.

The invention content is as follows:

a process for preparing barium sulfate and ferrous sulfide from ferrous sulfate and barium sulfide comprises the following steps:

1. preparation of barium sulfide

In order to prepare the soluble barium from the barite which is insoluble in water and acid, the barite is prepared by carrying out high-temperature reduction roasting on a reducing agent (anthracite) and the barite together. In addition, impurities such as silicon, iron, aluminum and the like in the barite can produce barium silicate from silicon, barium ferrite from iron and barium aluminate from aluminum during high-temperature roasting. Because these three barium compounds are insoluble in water, the leaching rate of barium is affected. For this reason, barite is required to contain BaSO₄More than 85%, and the self-explosion by heat energy is preferably used. The fixed carbon requirement of coal is more than 70%, the fixed carbon of coke is high, but the conversion rate of barium is low due to the influence of the treatment during coking on the activity and reducibility of the carbon, so that the method cannot be used. If the content of barite silicon is high (S)_iO₂More than 3 percent), limestone can be added into the material to lead the silicification to synthesize water-insoluble calcium silicate.

The barite and anthracite should be properly pulverized. If the particle size is too fine, not only is more electric energy consumed, but also excessive sintering affects reduction. Or the furnace charge is adhered to the furnace wall to affect operation, and the furnace charge is carried out by tail gas to pollute the environment, so the granularity of the furnace charge is preferably controlled to be less than 3 mm. Some barite with good self-explosion performance can be controlled to have a larger grain size.

Table 1: effect of feedstock particle size on conversion

Serial number	Particle size of mixed raw materials	BaS% in black ash	Serial number	Particle size of mixed raw materials	BaS% in black ash
						1	24 mesh	48.02	3	69 mesh screen	50.58
2	49 mesh screen	48.56	4	89 mesh screen	58.08

Mixing barite and anthracite according to the weight ratio of 100: 23-30, crushing, screening, placing in a storage device at the tail of a rotary furnace for storage, and quantitatively and continuously adding into a rotary furnace by using a spiral feeder. The length of the rotary furnace is different from 25 meters to 45 meters, the diameter is 1.5 meters to 2.5 meters, the inclination angle is 2-6 degrees, the rotating speed is 1-5 revolutions per minute, and clay refractory bricks are lined in the rotary furnace. And (3) carrying out countercurrent roasting on the coal gas at 1000-1200 ℃ for 1-2 hours until furnace burden is golden yellow melt, namely the reaction end point. And (3) enabling the melt to flow out of the rotating furnace end, entering a spiral leacher, leaching with hot water in a counter-current manner, controlling the temperature at 70 ℃ and the barium sulfide concentration at 14-17% and about 200 g/L, putting the leached barium sulfide solution into a clarifier, and standing and clarifying at 80 ℃ for later use. Since the harmful metals are insoluble in the alkaline leach solution, the solution is only soluble in barium sulfide. Therefore, the method can be used without impurity removal treatment and only by removing mechanical impurities through sedimentation. The slag is washed by water and then is put into a hydrochloric acid slag leaching tank for treatment. The reaction equation is as follows:

2. preparation of barium sulfate

Adding sodium sulfate (containing Na) with 50 deg.C hot water₂SO₄More than 85 percent, calcium (calculated by calcium sulfate) < 1.0 percent and magnesium (calculated by MgSO)₄)＜0.8％]Dissolving, and continuously heating to 90 ℃ to make the concentration of the sodium sulfate reach 20-26 DEG Be, namely 22-25%, and stopping adding the mirabilite. Heating Natrii sulfas solution with direct steam, adding lime, and sealing to remove magnesium and calcium (Mg)²⁺Less than 0.02 g/l, Ca²⁺< 0.015 g/l):

Mg²⁺+Ca(OH)₂＝Mg(OH)₂↓+Ca²⁺

Ca²⁺+Na₂CO₃＝Ca₂CO₃↓+2Na⁺

sodium sulfide and soda ash can be used to remove calcium and magnesium. Removing Mg by using sodium sulfide instead of lime²⁺Optionally mixing with Ca²⁺During the calcium removal, the consumption of soda ash can be reduced, and sodium sulfide as a byproduct can be used.

After removing magnesium and calcium, the solution is clarified for more than 20 hours, and the clear liquid is filtered and input into a metering tank. The settled mud is washed to recover mirabilite.

Mixing the barium sulfide solution with the mirabilite solution after calcium and magnesium removal, and heating to 80 ℃ to perform the following reactions:

barium hydroxide produced by hydrolysis of barium sulfide during BaS melt leaching (Ba (OH)₂Barium hydrosulfide [ Ba (HS) ]₂The reaction is as follows:

adding Na into the clear liquid₂SO₄No white precipitate appeared as the end point (slight barium excess). Then, clarification was performed. The clear liquid is 4% of sodium sulfide, and can be used as raw material for the next working procedure. And the precipitate is filtered, washed with warm water (the washing liquid contains Na)₂Discarding the solution after S is less than 0.02 percent), washing with dilute acid (the pH of the washing solution is 3-4), adjusting the pH to 5-6 with sulfuric acid, heating to 80 ℃, and adjusting the pH after acidification and slurrying, wherein excessive acid is not needed, so that the pH value of the product is influenced excessively, equipment is corroded, black FeS is generated, and the whiteness of the product is reduced. Then filtered and washed (end point Na)₂S is below 0.08 percent) to be dried, the water content of the barium cake is less than 25 percent, then the moisture can be reduced to below 0.2 percent after the barium cake is dried at the temperature of 250 ℃, and the barium cake is crushed into 325 meshes and then quantitatively packaged to obtain the barium sulfate product.

3. Preparation of ferrous sulfide

FeSO (ferric oxide) is added₄·7H₂Dissolving O in water, and adding Na in ②₂And (5) when the S solution generates black FeS precipitate, adding the solution until no blue appears after the clear solution is added with red blood salt for testing, and indicating that the iron is completely precipitated. And then continuously heating to boil for half an hour, standing for 1 hour, separating in a centrifuge, and washing filter residues with water. And (5) drying to obtain the ferrous sulfide. The filtrate is Na₂SO₄Returning to step ② for repeated use, the reaction equation is as follows:

the invention uses BaS liquid and Na₂SO₄Liquid reaction to prepare BaSO₄Precipitating, filtering to obtain Na₂And s, filtering the solution. Continuing to add Na₂FeS precipitate produced by the reaction of the solution s and the ferrous sulfate solution is filtered to obtain Na₂SO₄Solution of this Na₂SO₄Returning ② as raw material, and recycling, wherein Na + ion is selected from Na₂SO₄To Na₂S, then becomes Na₂SO₄. During the reaction, Na is added initially₂SO₄In the future, Na₂SO₄And Na₂And S is repeatedly recycled. This is to reduce Na in production₂SO₄And Na₂The raw material cost of S saves the cost and improves the economic benefit.

The raw materials of sodium sulfate and sodium sulfide required by the invention can be repeatedly returned for a long time and are not required to be purchased; ferrous sulfate is available in places where titanium dioxide is produced, and the price is very low; anthracite coal is commercially available from anywhere; the barite is rich in resources in China, and has rich mineral deposits in provinces such as Hunan, Hubei, Henan, Hebei, Shandong, Shanxi, Fujian, Guangxi, Guizhou and the like, wherein the quality of Guangxi and Guizhou is the best. The price is also inexpensive. It can be said that all the raw materials are inexpensive. And the barium sulfate product is 2500-3000 yuan per ton. The method aims to produce a barium sulfate plant which produces 5000 tons per year, the yield value can be more than one thousand and ten thousand per year, the cost is low, the profit is considerable, the required equipment is simple, the investment is not large, and the method is a short and even good project which is simple in equipment, low in investment, short in process, easy to apply, quick in effect, wide in application, low in cost and good in benefit.

The conditions of the product barium sulfate and ferrous sulfide of the invention will now be described in detail:

1. properties of barium sulfate: colorless orthorhombic crystals, or amorphous white powder, with a specific gravity of 4.499, melting point 1580 ℃, soluble in oleum and molten base, slightly soluble in boiling hydrochloric acid, and practically insoluble in water. Stable chemical property, easy to be made into mixed crystal by potassium permanganate, calcium carbonate or alkali metal nitrate, and reduced into barium sulfide by co-heating with carbon. It does not change color when meeting hydrogen sulfide or toxic gas in the air.

2. The quality requirement of barium sulfate is as follows: ministerial standard HG1-758-74

3. Use of barium sulfate: it can be used as filler for paint, ink, rubber, plastics and insulating cloth, surface coating agent for photographic paper and coated paper, sizing agent for textile and weighting agent for deep well drilling. It is also used in white pigment, ceramic, accumulator, enamel, perfume industry, contrast agent for X-ray gastrointestinal examination, and swelling agent for cathode plate.

4. Properties of ferrous sulfide

Ferrous sulfide is a dark brown or gray black crystal block or granule. The pure product is colorless, has a specific gravity of 4.74 and a melting point of 1193 ℃, is insoluble in water, is soluble in inorganic acid, and simultaneously emits toxic and combustible hydrogen sulfide gas. Gradually oxidized in humid air to be decomposed into sulfur and ferroferric oxide.

5. Use of ferrous sulfide

Ferrous sulfide is used in paper mill manufacture to produce sulfite solutions. Also used for making paints and pigments. Also used as reagents in analytical chemistry for the generation of H₂S, it can also be used for preparing sulfuric acid and ferric oxide.

Drawings

FIG. 1 is a flow chart of a process for preparing barium sulfate and ferrous sulfide from ferrous sulfate and barium sulfide.

Detailed Description

The process of the present invention will now be described with reference to the accompanying drawings: