CN1304876A - Process for preparing lead cyanamide - Google Patents
Process for preparing lead cyanamide Download PDFInfo
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- CN1304876A CN1304876A CN 00118206 CN00118206A CN1304876A CN 1304876 A CN1304876 A CN 1304876A CN 00118206 CN00118206 CN 00118206 CN 00118206 A CN00118206 A CN 00118206A CN 1304876 A CN1304876 A CN 1304876A
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- lead
- cyanamide
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- aminonitrile
- precipitate
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Abstract
A process for preparing lead cyanamide is prepared from calcium cyanamide and lead salt through reaction in aqueous solution. Its advantages are high reaction rate (8h), low temp up to 100 deg.C, easy control, no sewage drainage, and low cost.
Description
The invention relates to a cyanide compound, in particular to a preparation method of lead cyanamide.
Lead cyanamide is a yellow pigment, and is mainly used for high-grade coatings, paints and the like. U.S. Pat. No. 3,1111992 discloses a process for preparing lead cyanamide by high temperature solid phase reaction of lead oxide with a nitrogen-containing compound such as urea. The method is a solid-phase reaction, the reaction temperature is high (410-460 ℃), the energy consumption is large, the reaction time is long, and the reaction of lead oxide and urea to generate lead cyanamide can be completed in 45 hours. Even with the acceleration process, it still takes 26.5 hours.
The invention aims to provide a method for preparing lead cyanamide, which has short reaction time and can be carried out at normal temperature.
The technical scheme provided by the invention is as follows: the method for preparing the lead cyanamide by using the lime nitrogen and lead salt such as lead nitrate, lead acetate or lead chloride as main raw materials and reacting in an aqueous solution comprises the following steps:
1. hydrolyzing lime nitrogen to generate amino nitrile, and introducing CO in the hydrolysis process to promote hydrolysis and remove calcium ions generated by hydrolysis2Formation of calcium ions as CaCO3Precipitation, the reaction equation is:
2. adjusting the pH value of the mother liquor, namely amino nitrile solution, to be 9-10 after filtering, then adding lead salt into the mother liquor, combining the amino nitrile with lead ions to generate lead cyanamide precipitate, wherein the reaction formula is as follows:
wherein X represents an anion of a soluble lead salt.
The lead cyanamide is filtered, washed, dried and ground to obtain the product.
In the above preparation steps, the lead salt is lead nitrate, lead acetate or lead chloride. In the step 2, the optimal pH value of the mother liquid aminonitrile solution is 9-10.
The filtrate contains a small amount of lead ions, and CO is introduced to prevent pollution2Lead ions are formed into basic lead carbonate (PbCO)3·Pb(OH)2) Precipitate, which can be widely used as a white pigment.
Compared with the prior art, the invention has the following characteristics: the preparation process is carried out in solution, the reaction speed is high and uniform, and the reaction can be completed in only 8 hours from the hydrolysis of the lime nitrogen to the drying of the product; the reaction conditions are mild, and the whole reaction process isThe drying is carried out at normal temperature, the drying temperature is not higher than 100 ℃, and the production is easy to control; during the preparation process, proper conditions are controlled, lead cyanamide appears as yellow precipitate, a small amount of lead ions still exist in the filtered mother liquor, and CO is introduced into the solution again2Lead ions form lead carbonate or basic lead carbonate precipitates which are excellent white pigments, the mother liquor returns to the lime nitrogen hydrolysis step after filtration, the whole process wastewater is recycled, and zero emission of industrial production can be realized; the raw material of the invention is lime nitrogen, and compared with urea, the lime nitrogen has the characteristics of easily available raw material, low price and the like, so that the production cost of the lead cyanamidecan be reduced.
Example 1
Weighing 25g of CaCN2Adding 200ml of water, and introducing CO under the stirring condition2After hydrolysis for 40 minutes, adding 200ml of water, continuing hydrolysis for 30 minutes, filtering, adjusting the pH of the solution to 9, slowly adding 130ml of 30 wt% lead nitrate solution, allowing a large amount of yellow precipitate to appear, standing, filtering, washing, drying and grinding the precipitate to obtain the finished product. Introducing CO into the filtrate again2A white precipitate was produced, and the mother liquor after filtration was supplemented to the hydrolysis step as hydrolysis water.
Example 2
Weighing 25g of CaCN2Adding 200ml of water and introducing CO2Hydrolyzing for 40 minutes under stirring, adding 200ml of water, hydrolyzing for 30 minutes, filtering, adjusting the pH of the solution to 10, slowly adding 130ml of 33 wt% lead nitrate solution, allowing a large amount of yellow precipitate to appear, standing, filtering, washing, drying and grinding the precipitate to obtain the finished product. Introducing CO into the filtrate again2White precipitate is generated, and the mother liquor returns to the hydrolysis step after filtration.
Claims (4)
1. The preparation process of lead cyanamide features that lime nitrogen and lead salt as main material are reacted in water solution to produce lead cyanamide, and includes the following steps:
(1) lime nitrogen is hydrolyzed to form aminonitrile, and the hydrolyzed productIntroducing CO into the process2Formation of calcium ions as CaCO3Precipitation, the reaction equation is:
(2) adjusting the pH value of the mother liquor aminonitrile solution to 8-11 after filtering, then adding a lead salt solution into the mother liquor aminonitrile solution, combining aminonitrile with lead ions to generate a lead cyanamide precipitate, wherein the reaction formula is as follows:
wherein X represents an anion of a soluble lead salt
(3) Filtering, washing, drying and grinding the lead cyanamide precipitate to obtain the product.
2. The method according to claim 1, wherein the lead salt is lead nitrate, lead acetate or lead chloride.
3. The method for preparing lead cyanamide according to claim 1 or 2, wherein the mother liquor aminonitrile solution in the step (2) has an optimum pH of 9 to 10.
4. The method for preparing lead cyanamide according to claim 1 or 2, wherein CO is introduced into the filtrate after filtering the lead cyanamide precipitate2Lead ions are formed into white pigment basic lead carbonate (PbCO)3·Pb(OH)2) And (4) precipitating.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB001182064A CN1139538C (en) | 2000-06-01 | 2000-06-01 | Process for preparing lead cyanamide |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB001182064A CN1139538C (en) | 2000-06-01 | 2000-06-01 | Process for preparing lead cyanamide |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1304876A true CN1304876A (en) | 2001-07-25 |
| CN1139538C CN1139538C (en) | 2004-02-25 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB001182064A Expired - Fee Related CN1139538C (en) | 2000-06-01 | 2000-06-01 | Process for preparing lead cyanamide |
Country Status (1)
| Country | Link |
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| CN (1) | CN1139538C (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110228817A (en) * | 2019-06-10 | 2019-09-13 | 陕西师范大学 | A method of preparing a nanometer cyanogen ammonification indium powder |
| CN112551551A (en) * | 2020-11-25 | 2021-03-26 | 山东益丰生化环保股份有限公司 | Method for preparing high-end lime nitrogen from organic calcium salt |
-
2000
- 2000-06-01 CN CNB001182064A patent/CN1139538C/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110228817A (en) * | 2019-06-10 | 2019-09-13 | 陕西师范大学 | A method of preparing a nanometer cyanogen ammonification indium powder |
| CN112551551A (en) * | 2020-11-25 | 2021-03-26 | 山东益丰生化环保股份有限公司 | Method for preparing high-end lime nitrogen from organic calcium salt |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1139538C (en) | 2004-02-25 |
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