Heptahydrate crystal and preparation method

A technology of zinc sulfate heptahydrate and crystals, which is applied in the field of waste water resource treatment, can solve problems such as complex production process, low product purity, and poor thermal stability, and achieve simple and easy-to-control operating conditions, smooth crystal surface, and good thermal stability Effect

Active Publication Date: 2016-01-27
CHINA TIANCHEN ENG +1
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Problems solved by technology

Patent CN102515254B proposes four steps to realize the conversion of zinc sulfate solution into zinc sulfate heptahydrate crystals, which also ignores the regulation of crystal morphology indicators, and ignores the influence of macroscopic morphology, purity and metal impurity ion content of crystal products on the quality of crystal products
Feng Lin and others studied the thermodynamic stability of zinc sulfate heptahydrate produced by Chongqing Beibei Chemical Reagent Factory in "A Preliminary Study on the Dehydration Mechanism of Zinc Sulfate Heptahydrate Thermodynamics" (Journal of Chongqing Normal University, 2006, 3, 55-57). It shows that the dehydration process of zinc sulfate heptahydrate is divided into three steps, one molecule of crystal water will be lost at 41.5°C, and the seven molecules of crystal

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  • Heptahydrate crystal and preparation method
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  • Heptahydrate crystal and preparation method

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Example Embodiment

[0032] Example 1

[0033] Weigh 200.0 g of a binary solvent of methanol and ultrapure water, and the mass fraction of methanol is 20%. Add refined concentrated sulfuric acid dropwise, the mass ratio of sulfuric acid to binary solvent is 0.5:1; add zinc carbonate three times according to the molar ratio of zinc source to sulfuric acid of 1:1, reaction temperature is 50℃, reaction time is 30min; twice; Add refined concentrated sulfuric acid, the molar ratio of zinc source to sulfuric acid is 1:0.25, and react for 30 minutes; the solution is reduced to 5.0°C at a cooling rate of 0.2°C / min and kept at a constant temperature for 30 minutes; the suspension is suction filtered, and methanol and ultra Pure water binary solvent (w methanol = 20%) is used as the detergent to wash the filter cake. The volume ratio of the detergent to the initial methanol and ultrapure water binary solvent (200.0g) is 0.5:1; at -40℃, vacuum The filter cake was dried at a temperature of 0.08 MPa to obtain 26...

Example Embodiment

[0034] Example 2

[0035] Weigh 200.0 g of a binary solvent of ethanol and ultrapure water, and the mass fraction of ethanol is 50%. Add refined concentrated sulfuric acid dropwise, the mass ratio of sulfuric acid to binary solvent is 0.2:1; add zinc oxide three times according to the molar ratio of zinc source to sulfuric acid of 1:1, reaction temperature is 60℃, reaction time is 10min; twice; Add refined concentrated sulfuric acid, the molar ratio of zinc source to sulfuric acid is 1:0.05, and react for 30 minutes; the solution is reduced to 10.0°C at a cooling rate of 0.5°C / min and kept at a constant temperature for 60 minutes; the suspension is suction filtered, and ethanol and ultra The pure water binary solvent (w ethanol=50%) is used as the detergent to wash the filter cake. The volume ratio of the detergent to the initial methanol and ultrapure water binary solvent (200.0g) is 0.5:1; at -20℃, vacuum The filter cake was dried at a temperature of 0.10 MPa to obtain 106.58 ...

Example Embodiment

[0036] Example 3

[0037] Weigh 200.0 g of a binary solvent of isopropanol and ultrapure water, and the mass fraction of isopropanol is 35%. Add refined concentrated sulfuric acid dropwise, the mass ratio of sulfuric acid to the binary solvent is 0.3:1; add the binary mixture of zinc oxide and zinc hydroxide three times according to the molar ratio of zinc source to sulfuric acid of 1:1 (the molar ratio is 1:1: 1), the reaction temperature is 55℃, the reaction time is 20min; the second time is supplemented with refined concentrated sulfuric acid, the molar ratio of zinc source to sulfuric acid is 1:0.10, and the reaction is 20min; the solution is reduced to 5.0 at a cooling rate of 1.0℃ / min ℃, constant temperature for 60min; suction filter the suspension, and use isopropanol and ultrapure water binary solvent (w isopropanol = 35%) as the detergent to wash the filter cake, the detergent and the initial methanol and ultrapure water The volume ratio of the original solvent (200.0g)...

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Abstract

The invention provides a heptahydrate crystal and a preparation method. The preparation method includes the following steps that 1, sulfuric acid is dissolved in reaction liquid, and the reaction liquid is binary solvent and/or crystallization mother liquor of alcohol and water; 2, a zinc source is added, the molar ratio of the zinc source to sulfuric acid is controlled to be 1:1+/-0.1), and a reaction is conducted for a certain time; 3, sulfuric acid is supplemented, the molar ratio of the supplemented sulfuric acid and the zinc source added in step 2 is controlled to be (0.05-0.25):1, and the reaction is continued for a certain time; 4, after the reaction is ended, a solution is cooled and separated, the separated solid is subjected to postprocessing, and a product of the heptahydrate crystal is obtained. The product of the heptahydrate crystal has obvious prism-shaped crystallization habit, and dewatering endothermic peaks exist at the temperature of 75+/-1 DGE C, the temperature of 103 +/-1DEG C, the temperature of 124+/-1 DEG C and the temperature of 276+/-1 DEG C of a differential scanning calorimetric curve.

Description

technical field [0001] The invention belongs to the technical field of wastewater resource treatment, and in particular relates to a crystallization and separation method for ammonia nitrogen in ammonia-exchange wastewater, and is especially suitable for the treatment of ammonia-exchange wastewater by SAPO molecular sieves. Background technique [0002] Zinc Sulfate Heptahydrate, also known as Zinc Sulfate and Haolum, the English name is ZincSulfateHeptahydrated, and the molecular formula is ZnSO 4 ·7H 2 O, the molar mass is 287.54g / mol, and the CAS number is 7446-20-0. Zinc sulfate heptahydrate is a very important industrial raw material, widely used in chemical industry, medicine, agriculture, electrolysis, electroplating and other fields. Zinc sulfate heptahydrate is the main raw material for the production of zinc salt and lithopone. It can also be used as a bleaching agent, leather preservative, wood preservative, animal glue clarifying agent, etc.; it is used as an e...

Claims

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Application Information

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IPC IPC(8): C01G9/06
Inventor 杨利强耿玉侠马国栋钱震王志文张媛刘文王亮吕睿李玉龙王曙光王永昌
Owner CHINA TIANCHEN ENG
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