Preparation method of byproduct high-purity calcium sulphate by deep purification of nitrate aqueous solution

A deep purification, calcium sulfate technology, applied in the direction of calcium/strontium/barium sulfate, flocculation/precipitation water/sewage treatment, etc., can solve the problems of reducing the flow of nitrate water, perforation, rising energy consumption, etc., to achieve good purification effect, Simple process and low cost effect

Inactive Publication Date: 2013-07-24
何京明
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The main hazards after fouling are: (1) After the inner wall of the heating tube is fouled, the heating effect will decrease and the energy consumption will increase. In severe cases, it must be shut down for cleaning
According to relevant information, when the scale thickness in the heat exchanger of water-cooling equipment is 2.16mm, the heat transfer coefficient will drop by 51% on average, and the equipment operation efficiency will drop by 50%.
(2) Increase the water flow resistance of the heat exchange system, reduce the flow of nitric water, and increase the energy consumption of the circulating pump
(3) Local corrosion or even rupture and perforation will occur in the lower part of the nitrate scale attachment, seriously affecting the safe operation of the equipment
(4) The heat exchange system frequently washes tanks during operation, which requires interruption of production operation, increases the energy consumption of circulating pumps and water, and reduces production efficiency
[0008] At present, domestic and foreign nitrate production or salt nitrate co-production enterprises generally adopt the caustic soda-soda ash method for purifying nitrate water, which requires less investment in basic construction and simple process flow. rise
In addition, general enterprises control the calcium and magnesium content of nitric water purification treatment indicators to be higher than 20mg / L, and some enterprises reach 90mg / L, and the treatment cost is between 30 and 60 yuan / ton of nitric acid
However, the treated nitric water still contains a small amount of Ca 2+ , Mg 2+ ions, there are still scaling factors

Method used

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  • Preparation method of byproduct high-purity calcium sulphate by deep purification of nitrate aqueous solution

Examples

Experimental program
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Effect test

Embodiment 1

[0028] Take 10 liters of nitric water, which contains Mg 2+ 0.32g / L, Ca 2+ 0.69g / L, Na 2 SO 4 220g / L, Cl - 7g / L. When purifying and treating nitric water, first prepare lime emulsion: take 50g of quicklime and put it into a lime digester, add 300g of water, stir evenly, and obtain lime emulsion.

[0029] Add lime emulsion, calcium hydroxide and magnesium ions (Mg 2+ ) reacts to generate magnesium hydroxide to remove magnesium ions, and excess calcium hydroxide removes Na 2 SO 4 Causticize into NaOH, when the generated NaOH content reaches 1.5g / L, stop adding lime emulsion; continue to react at room temperature for 0.5h, add flocculant sodium polyacrylate, the usage amount is 1ppm, precipitate and clarify for 6h, filter; add phosphoric acid (about 13g of 80% phosphoric acid), adjust the pH value to 9.5; stir and react at room temperature for about 1h, add 1ppm flocculant sodium polyacrylate, let stand for 6h, filter, and the filtrate is refined nitric water. After testin...

Embodiment 2

[0032] Take 10 liters of brine, which contains Mg 2+ 0.40g / L, Ca 2+ 0.76g / L, Na 2 SO 4 20g / L, NaCl297g / L. When purifying brine, first prepare lime emulsion: take 100g of quicklime and put it into a lime digester, add 500g of water, stir evenly to obtain lime emulsion. Add lime emulsion under stirring of brine, excess calcium hydroxide 2 SO 4 Causticize to NaOH, when the generated NaOH content reaches 2.0g / L, stop adding lime emulsion; continue to react at room temperature for 45min, add cationic polyacrylamide, the usage amount is 3ppm, precipitate and clarify for 4h, filter; add phosphoric acid (about 14g80% Phosphoric acid), adjust the pH value to 11.0; stir and react at room temperature for about 1 hour, add 3 ppm cationic polyacrylamide, let stand for 4 hours, filter, the filtrate is refined brine, after testing, the refined brine has no calcium and magnesium ions;

[0033] Add clear water to the filter residue to make a slurry with a solid content of 10-20%, add 20g...

Embodiment 3

[0035] Take 10 liters of nitric water, which contains Mg 2+ 0.36g / L, Ca 2+ 0.72g / L, Na 2 SO 4 230g / L, NaCl9g / L. When purifying and treating nitric water, first prepare lime emulsion: take 80g of quicklime and put it into a lime digester, add 500g of water, stir evenly, and obtain lime emulsion. Add lime emulsion under nitrate stirring, excess calcium hydroxide 2 SO 4 Causticize into NaOH, when the NaOH content of generation reaches 2.5g / L, stop adding lime emulsion; Continue to react at room temperature for 1h, add sodium polyacrylate, use amount is 5ppm, precipitate and clarify for 2h, filter; filtrate adds phosphoric acid (about 12g80% Phosphoric acid), adjust the pH value to 12.0; stir and react at room temperature for about 1 hour, add 5 ppm of sodium polyacrylate, let it stand for 2 hours, filter, and the filtrate is refined nitric water. After testing, the refined nitric water has no calcium and magnesium ions;

[0036] Add clear water to the filter residue to make...

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Abstract

The invention provides a preparation method of byproduct high-purity calcium sulphate by deep purification of nitrate aqueous solution. The preparation method is characterized by comprising the following steps of: adding lime cream into nitrate aqueous solution to generate magnesium hydroxide precipitate; adding 1-5ppm of floculant, still standing the solution for 2-6 h, and carrying out settling separation; adding phosphoric acid to supernatant liquid and regulating the pH value of the solution to 9.5-12 to generate calcium phosphate precipitate; then adding 1-5ppm of floculant, still standing the solution for 2-6h, and carrying out settling separation, wherein the supernatant is pure nitrate aqueous solution and the residue is calcium phosphate; treating the residue calcium phosphate by using concentrated sulfuric acid to generate phosphoric acid and calcium sulphate and filtering by pressure to obtain the filtrate phosphoric acid for removing the next batch of material calcium ion; washing the residue by clear water to neutral state and drying the product to obtain high-purify calcium sulphate. The method disclosed in the invention adopts low-cost lime and sulphuric acid to deeply purify the nitrate aqueous solution so as to to obtain the high-purity nitrate aqueous solution and the high-purity calcium sulphate, and is simple in process and low in cost.

Description

technical field [0001] The present invention relates to a kind of Glauber's salt (Na 2 SO 4 ) The method for deep purification of nitric water in the production process to remove calcium and magnesium impurities, and by-product high-purity calcium sulfate belongs to the field of chemical industry. Background technique [0002] More than 90% of the anhydrous Glauber's salt in my country is made from the extremely rich natural Glauber's salt ore. The crude salt water is not only the main component Na 2 SO 4 In addition, it also contains; Na 2 CO 3 , NaHCO 3 , NaCl, CaSO 4 , MgSO 4 , MgCl and other chemical and mechanical impurities. In the process of evaporation nitrate production, as the temperature of nitrate water increases, substances with smaller crystal particles, such as CaSO 4 , CaCO 3 , Mg(OH) 2 The precipitated substances form magnesium hydroxide, calcium carbonate and calcium sulfate during the nitric water transportation, preheating and evaporation proce...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F1/56C01F11/46
Inventor 何京明
Owner 何京明
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