A preparation method of barium hydroxide octahydrate

Abstract

The present invention relates to the technical field of barium hydroxide, and discloses a method for preparing barium hydroxide octahydrate. The present invention reacts epoxy soybean oil and iminodiacetic acid to obtain an iminodiacetic acid modified epoxy soybean oil capture agent. With witherite ore as a raw material, the sodium iminodiacetic acid modified epoxy soybean oil capture agent, an inhibitor, and a foaming agent are added to separate and beneficiate the ore, and the separation recovery rate of the obtained high-grade witherite reaches 83.7-91.5%, and the grade reaches 57.7-63.8%. With high-grade witherite as a barium source, the yield of the prepared barium hydroxide octahydrate reaches 91.0-91.8%, and the purity reaches 97.5-98.7%.

Description

Technical Field

[0001] The invention relates to the technical field of barium hydroxide, in particular to a method for preparing barium hydroxide octahydrate. Background Art

[0002] Barium hydroxide is a common inorganic compound, widely used in metallurgy, petrochemical, construction and building materials. At present, barium hydroxide is mainly prepared from barium-containing minerals such as barite and witherite. The main components of witherite are barium titanate, barium sulfate, etc. It is a mineral resource with rich barium content and high-quality barium raw material. Using witherite as a raw material is an effective method for preparing barium compounds such as barium hydroxide and barium chloride.

[0003] At present, the reserves of high-grade witherite are scarce, while the barium content of medium- and low-grade witherite is low and there are more impurities. Using it as a barium source, the barium hydroxide, barium chloride and other products prepared have problems of low yield and purity. An invention patent with the publication number of CN102583480A discloses a method for preparing barium hydroxide octahydrate from barium witherite, and its classification number is C01F11. It uses barium witherite as raw material, graphite powder, sodium humate, paraffin wax, etc. as auxiliary agents, and has the advantages of high thermal decomposition efficiency and water leaching rate of witherite; another invention patent with the publication number of CN1079206A discloses a production method of barium hydroxide octahydrate, and its classification number is C01F11. This patent uses barium witherite as raw material, crushes it to 0.3-5 mm, adds 10-20% coal powder, roasts it in a downdraft kiln, and then leaches it with hot water, adds zinc oxide to the filtrate to remove sulfur, and then filters it. The filtrate is cooled and crystallized, and the crystals are dried to obtain the product, and the crystal mother liquor is returned to the leaching process for recycling. However, the purity of the witherite prepared by the methods of these patents is low. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] In view of the shortcomings of the prior art, the present invention provides a method for preparing barium hydroxide octahydrate, which solves the problem that the yield of the existing barium hydroxide octahydrate prepared by witherite is low and the purity is low.

[0006] (II) Technical solution

[0007] A method for preparing barium hydroxide octahydrate:

[0008] (1) The witherite ore is crushed, ball-milled and sieved to produce witherite fine powder.

[0009] (2) Add the witherite powder into the tank of the separator, then add water, stir for 2-3 minutes, adjust the pH to 6-8, and stir for 1-2 minutes.

[0010] (3) Add sodium iminodiacetic acid modified epoxy soybean oil capture agent into the tank and stir for 2-3 minutes.

[0011] (4) Add inhibitor to the tank and stir for 2-3 minutes.

[0012] (5) Add a foaming agent into the tank, stir for 3-5 minutes and scrape the foam; collect the foam, filter, and dry to obtain witherite.

[0013] (6) The witherite is calcined in a resistance furnace and then cooled to obtain crude barium oxide.

[0014] (7) Add water to the reaction kettle, heat to 85-90°C, add crude barium oxide, stir and leach for 40-60 minutes, filter and collect the filtrate; then add zinc oxide to the filtrate, stir to remove sulfur, filter and collect the filtrate, heat to evaporate and concentrate, cool and recrystallize to obtain barium hydroxide octahydrate.

[0015] Preferably, in (2), the ratio of witheringite powder to water is (150-220) g:1L.

[0016] Preferably, in (2), the mass of the sodium iminodiacetic acid modified epoxy soybean oil capture agent is 5-12% of the mass of the witherite micropowder.

[0017] Preferably, the mass of the inhibitor is 3-7% of the mass of the witherite micropowder; the inhibitor is citric acid or tartaric acid.

[0018] Preferably, in (6), the calcination temperature is 950-1100°C and the calcination time is 3-5h.

[0019] Preferably, in (7), the ratio of water to crude barium oxide is 1 L: (150-200) g.

[0020] Preferably, the preparation method of the sodium iminodiacetate modified epoxy soybean oil capture agent is: add 1,4-dioxane, epoxy soybean oil, 45-60% of the mass of the epoxy soybean oil iminodiacetic acid into a reaction bottle, dropwise add a sodium hydroxide aqueous solution with a mass concentration of 100-150 g / L, adjust the pH to 8-9, heat to 70-85°C, stir and react for 12-18 hours, remove low-boiling substances by reduced pressure distillation after the reaction, add water for dilution, extract with dichloromethane, dry the organic phase after separation, and distill under reduced pressure to obtain the sodium iminodiacetate modified epoxy soybean oil capture agent.

[0021] (III) Technical Effect

[0022] The invention utilizes the imino group of iminodiacetic acid to carry out ring-opening reaction with the epoxy group of epoxy soybean oil, thereby introducing multiple carboxyl functional groups into the molecular chain of epoxy soybean oil to obtain the sodium iminodiacetic acid modified epoxy soybean oil capture agent.

[0023] The present invention uses sodium iminodiacetic acid modified epoxy soybean oil as a trapping agent for witherite. The trapping agent contains multiple carboxyl groups, has strong adsorption and coordination capabilities, and can be well adsorbed on the surface of witherite. At the same time, the epoxy soybean oil trapping agent contains multiple hydrophobic alkyl chains, which can change the hydrophobicity of the surface of witherite, improve its adhesion to bubbles, and improve the floatability of witherite, so that the witherite can be well adhered to the bubbles and float, thereby making the witherite easier to be separated. After separation, the separation recovery rate of the witherite reaches 83.7-91.5%, and the grade reaches 57.7-63.8%.

[0024] The high-grade witherite of the invention has high barium content and few impurities. By using the witherite as a barium source and undergoing high-temperature hot-dip treatment, the yield of the obtained barium hydroxide octahydrate reaches 91.0-91.8% and the purity reaches 97.5-98.7%. DETAILED DESCRIPTION

[0025] In order to make the purpose, implementation mode and advantages of the present application clearer, the exemplary implementation mode of the present application will be clearly and completely described below in combination with the exemplary embodiments of the present application. Obviously, the described exemplary embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0026] Example 1

[0027] (1) Add 400 mL of 1,4-dioxane, 60 g of epoxy soybean oil, and 32 g of iminodiacetic acid into a reaction bottle, add a sodium hydroxide aqueous solution with a mass concentration of 120 g / L, adjust the pH to 9, raise the temperature to 70°C, and stir to react for 18 hours. After the reaction, remove low-boiling substances by vacuum distillation, add water for dilution, extract with dichloromethane, and after separation, dry the organic phase and vacuum distill to obtain a sodium iminodiacetic acid modified epoxy soybean oil capture agent.

[0028] (2) The witherite ore is crushed, ball-milled and passed through a 200-mesh sieve to produce witherite fine powder.

[0029] (3) Add 1.5 kg of witherite powder into the separator tank, then add 10 L of water, stir for 2 minutes, adjust the pH to 8, and stir for 1 minute.

[0030] (4) Add 90 g of sodium iminodiacetic acid modified epoxy soybean oil capture agent into the tank and stir for 3 minutes.

[0031] (5) Add 45 g of inhibitor citric acid into the tank and stir for 3 minutes.

[0032] (6) Add 18g of foaming agent BK201 to the tank, stir for 3 min and scrape the foam; collect the foam, filter and dry to obtain high-grade witherite. Weigh and record it as m 1 Filter, dry and weigh the solution at the bottom of the tank, record it as m 2 . Calculate the separation recovery rate R. R=m 1 / (m 1 + m 2 )×100%.

[0033] (7) High-grade witherite is placed in a resistance furnace and heated to 1000°C at a heating rate of 5°C / min. The temperature is kept constant and calcined for 5 h. After cooling, crude barium oxide is obtained.

[0034] (8) Add 1L of water to the reactor, heat to 90°C, add 150g of crude barium oxide, stir and leach for 60min, filter and collect the filtrate; then add 7g of zinc oxide to the filtrate, stir to remove sulfur, filter and collect the filtrate, heat and evaporate to concentrate, cool and recrystallize to obtain barium hydroxide octahydrate. Weigh and record as m. Calculate the yield. Yield = m / m 0 ×100%,m 0 is the mass of crude barium oxide.

[0035] Example 2

[0036] (1) Add 400 mL of 1,4-dioxane, 60 g of epoxy soybean oil, and 27 g of iminodiacetic acid into a reaction bottle, add a sodium hydroxide aqueous solution with a mass concentration of 150 g / L, adjust the pH to 8, raise the temperature to 85°C, and stir to react for 12 hours. After the reaction, remove low-boiling substances by vacuum distillation, add water for dilution, extract with dichloromethane, and after separation, dry the organic phase and vacuum distill to obtain a sodium iminodiacetic acid modified epoxy soybean oil capture agent.

[0037] (2) The witherite ore is crushed, ball-milled and passed through a 200-mesh sieve to produce witherite fine powder.

[0038] (3) Add 2 kg of witherite powder into the separator tank, then add 10 L of water, stir for 2 minutes, adjust the pH to 7, and stir for 2 minutes.

[0039] (4) Add 240 g of sodium iminodiacetic acid modified epoxy soybean oil capture agent into the tank and stir for 2 minutes.

[0040] (5) Add 100 g of inhibitor tartaric acid into the tank and stir for 3 minutes.

[0041] (6) Add 25g of foaming agent to the tank, stir for 3 minutes and scrape the foam; collect the foam, filter and dry it to obtain high-grade witherite. Weigh it and record it as m 1Filter, dry and weigh the solution at the bottom of the tank, record it as m 2 . Calculate the separation recovery rate R. R=m 1 / (m 1 + m 2 )×100%.

[0042] (7) High-grade witherite is placed in a resistance furnace and heated to 950°C at a heating rate of 5°C / min. The temperature is kept constant and calcined for 5 h. After cooling, crude barium oxide is obtained.

[0043] (8) Add 1L of water to the reactor, heat to 90°C, add 180g of crude barium oxide, stir and leach for 40min, filter and collect the filtrate; then add 8g of zinc oxide to the filtrate, stir to remove sulfur, filter and collect the filtrate, heat and evaporate to concentrate, cool and recrystallize to obtain barium hydroxide octahydrate. Weigh and record as m. Calculate the yield. Yield = m / m 0 ×100%,m 0 is the mass of crude barium oxide.

[0044] Example 3

[0045] (1) Add 300 mL of 1,4-dioxane, 60 g of epoxy soybean oil, and 36 g of iminodiacetic acid to a reaction bottle, add a sodium hydroxide aqueous solution with a mass concentration of 100 g / L, adjust the pH to 9, raise the temperature to 80°C, and stir to react for 12 hours. After the reaction, remove low-boiling substances by vacuum distillation, add water for dilution, extract with dichloromethane, and after separation, dry the organic phase and vacuum distill to obtain a sodium iminodiacetic acid modified epoxy soybean oil capture agent.

[0046] (2) The witherite ore is crushed, ball-milled and passed through a 200-mesh sieve to produce witherite fine powder.

[0047] (3) Add 2 kg of witherite powder into the separator tank, then add 10 L of water, stir for 2 minutes, adjust the pH to 6, and stir for 1 minute.

[0048] (4) Add 100 g of sodium iminodiacetic acid modified epoxy soybean oil capture agent into the tank and stir for 3 minutes.

[0049] (5) Add 140 g of inhibitor citric acid into the tank and stir for 3 minutes.

[0050] (6) Add 20g of foaming agent to the tank, stir for 5 minutes and scrape the foam; collect the foam, filter and dry it to obtain high-grade witherite. Weigh it and record it as m 1 Filter, dry and weigh the solution at the bottom of the tank, record it as m 2 . Calculate the separation recovery rate R. R=m 1 / (m 1+ m 2 )×100%.

[0051] (7) High-grade witherite is placed in a resistance furnace and heated to 1000°C at a heating rate of 5°C / min. The temperature is kept constant and calcined for 3 h. After cooling, crude barium oxide is obtained.

[0052] (8) Add 1L of water to the reactor, heat to 85°C, add 150g of crude barium oxide, stir and leach for 60min, filter and collect the filtrate; then add 7g of zinc oxide to the filtrate, stir to remove sulfur, filter and collect the filtrate, heat and evaporate to concentrate, cool and recrystallize to obtain barium hydroxide octahydrate. Weigh and record as m. Calculate the yield. Yield = m / m 0 ×100%,m 0 is the mass of crude barium oxide.

[0053] Example 4

[0054] (1) Add 300 mL of 1,4-dioxane, 60 g of epoxy soybean oil, and 27 g of iminodiacetic acid into a reaction bottle, add a sodium hydroxide aqueous solution with a mass concentration of 100 g / L, adjust the pH to 9, raise the temperature to 70°C, and stir to react for 18 hours. After the reaction, remove low-boiling substances by vacuum distillation, add water for dilution, extract with dichloromethane, and after separation, dry the organic phase and vacuum distill to obtain a sodium iminodiacetic acid modified epoxy soybean oil capture agent.

[0055] (2) The witherite ore is crushed, ball-milled and sieved through a 300-mesh sieve to produce witherite fine powder.

[0056] (3) Add 2.2 kg of witherite powder into the separator tank, then add 10 L of water, stir for 2 minutes, adjust the pH to 8, and stir for 1 minute.

[0057] (4) Add 220 g of sodium iminodiacetic acid modified epoxy soybean oil capture agent into the tank and stir for 2 minutes.

[0058] (5) Add 150 g of inhibitor citric acid into the tank and stir for 3 minutes.

[0059] (6) Add 20g of foaming agent to the tank, stir for 5 minutes and scrape the foam; collect the foam, filter and dry it to obtain high-grade witherite. Weigh it and record it as m 1 Filter, dry and weigh the solution at the bottom of the tank, record it as m 2 . Calculate the separation recovery rate R. R=m 1 / (m 1 + m 2 )×100%.

[0060] (7) High-grade witherite is placed in a resistance furnace and heated to 1100°C at a heating rate of 5°C / min. The temperature is kept for calcination for 4 h and crude barium oxide is obtained after cooling.

[0061] (8) Add 1L of water to the reactor, heat to 85°C, add 200g of crude barium oxide, stir and leach for 60min, filter and collect the filtrate; then add 10g of zinc oxide to the filtrate, stir to remove sulfur, filter and collect the filtrate, heat to evaporate and concentrate, cool and recrystallize to obtain barium hydroxide octahydrate. Weigh and record as m. Calculate the yield. Yield = m / m 0 ×100%,m 0 is the mass of crude barium oxide.

[0062] Comparative Example 1

[0063] (1) The witherite ore is crushed, ball-milled and passed through a 200-mesh sieve to produce witherite fine powder.

[0064] (2) Add 1.5 kg of witherite powder into the separator tank, then add 10 L of water, stir for 2 minutes, adjust the pH to 8, and stir for 1 minute.

[0065] (3) Add 90 g of epoxidized soybean oil as a capture agent into the tank and stir for 3 min.

[0066] (4) Add 45 g of inhibitor citric acid into the tank and stir for 3 minutes.

[0067] (5) Add 18g of foaming agent BK201 to the tank, stir for 3 min and scrape the foam; collect the foam, filter and dry to obtain high-grade witherite. Weigh and record it as m 1 Filter, dry and weigh the solution at the bottom of the tank, record it as m 2 . Calculate the separation recovery rate R. R=m 1 / (m 1 + m 2 )×100%.

[0068] (6) High-grade witherite is placed in a resistance furnace, heated to 1000°C at a heating rate of 5°C / min, and calcined for 5 hours. After cooling, crude barium oxide is obtained.

[0069] (7) Add 1L of water to the reactor, heat to 90°C, add 150g of crude barium oxide, stir and leach for 60min, filter and collect the filtrate; then add 7g of zinc oxide to the filtrate, stir to remove sulfur, filter and collect the filtrate, heat and evaporate to concentrate, cool and recrystallize to obtain barium hydroxide octahydrate. Weigh and record as m. Calculate the yield. Yield = m / m 0 ×100%,m 0 is the mass of crude barium oxide.

[0070] Comparative Example 2

[0071] (1) The witherite ore is crushed, ball-milled and passed through a 200-mesh sieve to produce witherite fine powder.

[0072] (2) Add 1.5 kg of witherite powder into the separator tank, then add 10 L of water, stir for 2 minutes, adjust the pH to 8, and stir for 1 minute.

[0073] (3) Add 90 g of iminodiacetic acid as a capture agent into the tank and stir for 3 minutes.

[0074] (4) Add 45 g of inhibitor citric acid into the tank and stir for 3 minutes.

[0075] (5) Add 18g of foaming agent BK201 to the tank, stir for 3 min and scrape the foam; collect the foam, filter and dry to obtain high-grade witherite. Weigh and record it as m 1 Filter, dry and weigh the solution at the bottom of the tank, record it as m 2 . Calculate the separation recovery rate R. R=m 1 / (m 1 + m 2 )×100%.

[0076] (6) High-grade witherite is placed in a resistance furnace, heated to 1000°C at a heating rate of 5°C / min, and calcined for 5 hours. After cooling, crude barium oxide is obtained.

[0077] (7) Add 1L of water to the reactor, heat to 90°C, add 150g of crude barium oxide, stir and leach for 60min, filter and collect the filtrate; then add 7g of zinc oxide to the filtrate, stir to remove sulfur, filter and collect the filtrate, heat and evaporate to concentrate, cool and recrystallize to obtain barium hydroxide octahydrate. Weigh and record as m. Calculate the yield. Yield = m / m 0 ×100%,m 0 is the mass of crude barium oxide.

[0078] Comparative Example 3

[0079] (1) The witherite ore is crushed, ball-milled and passed through a 200-mesh sieve to produce witherite fine powder.

[0080] (2) Add 1.5 kg of witherite powder into the separator tank, then add 10 L of water, stir for 2 minutes, adjust the pH to 8, and stir for 1 minute.

[0081] (3) Add 90 g of sodium oleate as a capture agent into the tank and stir for 3 minutes.

[0082] (4) Add 45 g of inhibitor citric acid into the tank and stir for 3 minutes.

[0083] (5) Add 18g of foaming agent BK201 to the tank, stir for 3 min and scrape the foam; collect the foam, filter and dry to obtain high-grade witherite. Weigh and record it as m 1 Filter, dry and weigh the solution at the bottom of the tank, record it as m 2 . Calculate the separation recovery rate R. R=m 1 / (m 1 + m 2 )×100%.

[0084] (6) High-grade witherite is placed in a resistance furnace, heated to 1000°C at a heating rate of 5°C / min, and calcined for 5 hours. After cooling, crude barium oxide is obtained.

[0085] (7) Add 1L of water to the reactor, heat to 90°C, add 150g of crude barium oxide, stir and leach for 60min, filter and collect the filtrate; then add 7g of zinc oxide to the filtrate, stir to remove sulfur, filter and collect the filtrate, heat and evaporate to concentrate, cool and recrystallize to obtain barium hydroxide octahydrate. Weigh and record as m. Calculate the yield. Yield = m / m 0 ×100%,m 0 is the mass of crude barium oxide.

[0086] The grade calculation method of high-grade witherite, grade = M 1 / M×100%. M is the total mass of high-grade witherite, M 1 is the mass of barium carbonate in high-grade witherite. The separation recovery rate and high-grade witherite grade test results are shown in Table 1.

[0087] Table 1 Flotation recovery and high-grade witherite grade test

[0088] Separation recovery rate (%) grade(%) Example 1 85.1 59.4 Example 2 83.7 63.8 Example 3 91.5 57.7 Example 4 87.4 62.0 Comparative Example 1 7.6 40.9 Comparative Example 2 19.3 44.5 Comparative Example 3 72.8 53.6

[0089] After testing, when separating the witherite ore in Examples 1-4, sodium iminodiacetic acid modified epoxy soybean oil capture agent was added, and the separation recovery rate of high-grade witherite reached 83.7-91.5%, and the grade reached 57.7-63.8%.

[0090] Compared with Example 1, in Comparative Example 1, where epoxidized soybean oil was used as a capture agent, the separation recovery rate of witherite was only 7.6%, and the grade was only 40.9%.

[0091] Comparative Example 2: Using iminodiacetic acid as a capture agent, the separation recovery rate of witherite is only 19.3%, and the grade is only 44.5%.

[0092] Comparative Example 3: Conventional sodium oleate was used as the capture agent, and the separation recovery rate of witherite was 72.8%, and the grade was only 53.6%.

[0093] The yield and purity of barium hydroxide octahydrate in each embodiment and comparative example are shown in Table 2.

[0094] Table 2 Yield and purity test of barium hydroxide octahydrate

[0095] Yield (%) purity(%) Example 1 91.0 98.2 Example 2 91.8 98.0 Example 3 90.7 98.7 Example 4 91.4 97.5 Comparative Example 1 52.1 91.9 Comparative Example 2 55.6 90.3 Comparative Example 3 86.4 96.2

[0096] After testing, the yield of barium hydroxide octahydrate prepared by Examples 1-4 using high-grade witherite as raw material reached 91.0-91.8%, and the purity reached 97.5-98.7%.

[0097] The above content is a further detailed description of the present invention. It cannot be determined that the specific implementation methods of the present invention are limited to these. For ordinary technicians in the technical field to which the present invention belongs, without departing from the concept of the present invention, they can also make several simple deductions or substitutions, which should be regarded as belonging to the protection scope of the present invention determined by the submitted claims.

Claims

1. A method for preparing barium hydroxide octahydrate, characterized in that: The method is: (1) crushing the witherite ore, ball milling and screening to produce witherite fine powder; (2) Add the witherite powder into the tank of the separator, then add water, stir for 2-3 minutes, adjust the pH to 6-8, and stir for 1-2 minutes; (3) adding sodium iminodiacetate modified epoxy soybean oil capture agent to the tank body and stirring for 2-3 minutes; the preparation method of the sodium iminodiacetate modified epoxy soybean oil capture agent is: adding 1,4-dioxane, epoxy soybean oil, and iminodiacetic acid to a reaction bottle, dropping sodium hydroxide aqueous solution to adjust the pH to 8-9, stirring for reaction, and removing low-boiling substances by vacuum distillation after the reaction, adding water for dilution, extracting with dichloromethane, drying the organic phase after separation, and vacuum distilling to obtain the sodium iminodiacetate modified epoxy soybean oil capture agent; (4) Add inhibitor to the tank and stir for 2-3 minutes; (5) Add a foaming agent to the tank, stir for 3-5 minutes and scrape the foam; Collect the foam, filter, and dry to obtain high-grade witherite; after separation, the recovery rate of the witherite reaches 83.7-91.5%, and the grade reaches 57.7-63.8%, where the grade refers to the mass percentage of barium carbonate in the witherite; (6) calcining the high-grade witherite in a resistance furnace and obtaining crude barium oxide after cooling; (7) Add water to the reaction kettle, heat to 85-90°C, add crude barium oxide, stir and leach for 40-60 minutes, filter and collect the filtrate; then add zinc oxide to the filtrate, stir to remove sulfur, filter and collect the filtrate, heat to evaporate and concentrate, cool and recrystallize to obtain barium hydroxide octahydrate.

2. The method for preparing barium hydroxide octahydrate according to claim 1, characterized in that: In the above (2), the ratio of witheringite powder to water is (150-220) g:1L.

3. The method for preparing barium hydroxide octahydrate according to claim 1, characterized in that: In the above (2), the mass of the sodium iminodiacetic acid modified epoxy soybean oil capture agent is 5-12% of the mass of the witherite micropowder.

4. The method for preparing barium hydroxide octahydrate according to claim 1, characterized in that: The mass of the iminodiacetic acid is 45-60% of the mass of the epoxidized soybean oil.

5. The method for preparing barium hydroxide octahydrate according to claim 1, characterized in that: The mass concentration of the sodium hydroxide aqueous solution is 100-150 g / L.

6. The method for preparing barium hydroxide octahydrate according to claim 1, characterized in that: The reaction temperature is 70-85°C and the reaction time is 12-18h.

7. The method for preparing barium hydroxide octahydrate according to claim 1, characterized in that: The mass of the inhibitor is 3-7% of the mass of witherite micropowder; the inhibitor is citric acid or tartaric acid.

8. The method for preparing barium hydroxide octahydrate according to claim 1, characterized in that: In the above (6), the calcination temperature is 950-1100°C and the calcination time is 3-5h.

9. The method for preparing barium hydroxide octahydrate according to claim 1, characterized in that: In the above (7), the ratio of water to crude barium oxide is 1L: (150-200)g.