Technology and system for improving yield of nitric acid regenerated by stainless steel acid-washing waste liquid

A technology for pickling waste liquid and stainless steel, which is applied in the fields of nitric acid, nitrogen oxides/oxyacids, water/sludge/sewage treatment, etc. Absorption rate, the effect of improving yield

Active Publication Date: 2018-01-19
鞍山创鑫环保科技股份有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0020] However, in actual operation, the yield of nitric acid in the spray roasting method is always unsatisfactory, generally around 30%. The

Method used

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  • Technology and system for improving yield of nitric acid regenerated by stainless steel acid-washing waste liquid
  • Technology and system for improving yield of nitric acid regenerated by stainless steel acid-washing waste liquid
  • Technology and system for improving yield of nitric acid regenerated by stainless steel acid-washing waste liquid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0055] In this embodiment, the heat generated by natural gas combustion is used as the heat source to preheat the hydrolysis roaster 1, and then heated to the required temperature, wherein the furnace top temperature is 250°C, and the furnace bottom temperature is 650°C; the high-temperature flue gas enters the pre-concentrator In step 2, the pickling waste liquid is added to the pre-concentrator 2, and the pickling waste liquid is concentrated while cooling the high-temperature flue gas.

[0056] The composition of the processed stainless steel pickling waste liquor is as shown in table 1:

[0057] Table 1

[0058] Element

g / L

Ae (metal ion)

45

F ion

45

NO 3 -

145

total

235

[0059] Treat waste liquid 6m per hour 3 / h.

[0060] The composition of pickling waste liquid after pre-concentration in pre-concentrator 2 is shown in Table 2:

[0061] Table 2

[0062] Element

g / L

Ae (metal ion)

...

Embodiment 2

[0078] In this embodiment, the heat generated by natural gas combustion is used as the heat source to preheat the hydrolysis roaster 1, and then heated to the required temperature, wherein the furnace top temperature is 350°C, and the furnace bottom temperature is 750°C; the high-temperature flue gas enters the pre-concentrator In step 2, the pickling waste liquid is added to the pre-concentrator 2, and the pickling waste liquid is concentrated while cooling the high-temperature flue gas.

[0079] The composition of the processed stainless steel pickling waste liquor is as shown in table 6:

[0080] Table 6

[0081] Element

g / L

Ae (metal ion)

55

F ion

55

NO 3 -

165

total

280

[0082] Treat waste liquid 6m per hour 3 / h.

[0083] The composition of pickling waste liquid after pre-concentration in pre-concentrator 2 is shown in Table 7:

[0084] Table 7

[0085] Element

g / L

Ae (metal ion)

...

Embodiment 3

[0101] In this embodiment, the heat generated by natural gas combustion is used as the heat source to preheat the hydrolysis roaster 1, and then heated to the required temperature, wherein the furnace top temperature is 300°C, and the furnace bottom temperature is 700°C; the high-temperature flue gas enters the pre-concentrator In step 2, the pickling waste liquid is added to the pre-concentrator 2, and the pickling waste liquid is concentrated while cooling the high-temperature flue gas.

[0102] The composition of the processed stainless steel pickling waste liquor is as shown in table 11:

[0103] Table 11

[0104] Element

g / L

Ae (metal ion)

55

F ion

50

NO 3 -

150

total

255

[0105] Treat waste liquid 6m per hour 3 / h.

[0106] The composition of the pickling waste liquid after pre-concentration in the pre-concentrator 2 is shown in Table 12:

[0107] Table 12

[0108] Element

g / L

Ae (met...

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Abstract

The invention relates to a technology and a system for improving the yield of nitric acid regenerated by stainless steel acid-washing waste liquid. After the acid-washing waste liquid is concentratedby high-temperature flue gas in a pre-concentrator, the acid-washing waste liquid enters a hydrolysis and roasting furnace to be decomposed at high temperature; after flue gas containing HF, NOx and HNO3 enters the pre-concentrator and is subjected to dust removal and cooling, the flue gas enters an acid absorption tower to be subjected to acid absorption; then the flue gas is washed through a washing tower and is condensed by circulating cooling water in a condenser; condensed liquid is used as washing liquid to participate in washing in a washing tower; the washed washing liquid is used as absorption liquid of an acid absorption tower; the condensed gas enters a catalytic denitration device to be subjected to denitration reaction; after the NOx is removed, the flue gas is discharged after reaching the standards. By adopting the technology and the system, the flue gas is cooled before being subjected to the acid absorption, so that the absorption rate of the nitric acid is effectivelyimproved; meanwhile, an oxidant is sprayed into the flue gas and NO can be oxidized into high-valence substances including N2O5 and the like, so that the yield of the nitric acid is improved.

Description

technical field [0001] The invention relates to the technical field of regeneration treatment of metal pickling waste liquid, in particular to a process and a system for increasing the yield of regenerated nitric acid from stainless steel pickling waste liquid. Background technique [0002] In the stainless steel annealing and pickling production line, it is necessary to remove the iron oxide scale and chromium-poor layer on the surface of the strip steel by pickling, and passivate the surface of the strip steel to improve the corrosion resistance of the steel plate. Stainless steel cold strip pickling includes pre-pickling and mixed acid pickling. The pickling medium varies according to the variety of pickling strip steel. At present, Na 2 SO 4 Electrolytic pre-pickling+(HNO 3 +HF) mixed acid pickling. The waste pickling solution contains a large amount of free acid and combined acid radicals, which can be recycled to reduce the cost of pickling and waste water treatmen...

Claims

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Application Information

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IPC IPC(8): C02F1/16C23G1/36C01B21/42C01B21/46B01D53/86B01D53/56B01D53/18B01D53/14B01D53/00C02F101/14C02F101/16C02F101/20
Inventor 孟剑杨刚王云山孟祥全张贺玉刘坤
Owner 鞍山创鑫环保科技股份有限公司
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