A method for sorting and recovering heavy metals in waste nitric acid containing gold, copper and nickel

A recovery method and technology for waste nitric acid, which are applied in the improvement of process efficiency, instruments, optics, etc., to achieve the effects of high purity, good recovery rate, and easy process control

Active Publication Date: 2018-11-30
盛隆资源再生(无锡)有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, this method only recovers copper and nickel, and other metals are not reflected

Method used

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  • A method for sorting and recovering heavy metals in waste nitric acid containing gold, copper and nickel

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Take 1000L waste nitric acid, control the distillation pressure to be 0.04MPa, and the temperature is 100°C, carry out vacuum distillation, collect 900L dilute nitric acid, measure the acidity of dilute nitric acid to be 24.81%; add sodium hydroxide to the remaining 100L mother liquor to adjust the pH to 7.0, stir evenly, Filtrate to obtain a precipitate mainly composed of copper, nickel and gold and a filtrate mainly composed of sodium nitrate. The filtrate is controlled to distill at a pressure of 0.04MPa and a temperature of 100°C, and carry out vacuum distillation to prepare sodium nitrate crystals. The purity of the obtained sodium nitrate crystals is 99.11%;

[0028] Slowly add ammonia water to dissolve the above precipitate, then continue to add ammonia water to adjust the pH to 12, stir evenly, the total amount of ammonia water added is 10%, the total time of adding ammonia water is 2 hours, filter to obtain the filtrate mainly composed of copper and nickel and ...

Embodiment 2

[0032] Take 1500L waste nitric acid, control the distillation pressure to be 0.05MPa, and the temperature is 110°C, carry out vacuum distillation, collect 1350L dilute nitric acid, measure the acidity of dilute nitric acid to be 25.45%; add sodium hydroxide to the remaining 150L mother liquor to adjust the pH to 7.5, stir evenly, Filtrate to obtain a precipitate mainly composed of copper, nickel and gold and a filtrate mainly composed of sodium nitrate. The filtrate is controlled to distill at a pressure of 0.05MPa and a temperature of 110°C, and carry out vacuum distillation to prepare sodium nitrate crystals. The purity of the obtained sodium nitrate crystals is 99.34%;

[0033] Slowly add ammonia water to dissolve the above precipitate, then continue to add ammonia water to adjust the pH to 12.5, stir evenly, the total amount of ammonia water added is 11%, the total time of adding ammonia water is 2.5 hours, filter, and obtain filtrate mainly composed of copper and nickel an...

Embodiment 3

[0037]Take 2000L waste nitric acid, control the distillation pressure to be 0.06MPa, and the temperature is 120°C, carry out vacuum distillation, collect 1800L dilute nitric acid, measure the acidity of dilute nitric acid to be 25.22%; add sodium hydroxide to the remaining 200L mother liquor to adjust the pH to 8, stir evenly, Filtrate to obtain a precipitate mainly composed of copper, nickel, and gold and a filtrate mainly composed of sodium nitrate. The filtrate is controlled to have a distillation pressure of 0.06MPa and a temperature of 120°C, and carry out vacuum distillation to prepare sodium nitrate crystals. The purity of the obtained sodium nitrate crystals is 99.26%;

[0038] Slowly add ammonia water to dissolve the above precipitate, then continue to add ammonia water to adjust the pH to 13, stir evenly, the total amount of ammonia water added is 12%, the total time of adding ammonia water is 3 hours, filter, and obtain the filtrate mainly composed of copper and nick...

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Abstract

A classified recycling method for heavy metal in waste nitric acid containing gold, copper and nickel includes the steps that the waste nitric acid is subjected to reduced pressure distillation, and fraction dilute nitric acid is collected; sodium hydroxide is added to residual mother liquor obtained through distillation to regulate pH, and filtering is conducted; sodium nitrate crystals are prepared by distilling filtrate, ammonia water is added to sediment to dissolve the sediment, and filtrate containing gold-bearing sediment and mainly containing copper and nickel is obtained through filtering; aqua regia is added to the gold-bearing sediment to dissolve the gold-bearing sediment, then, sodium sulfite is added for reduction, and elementary gold is obtained; the elementary gold is subjected to high-temperature calcination, and high-hardness and high-purity gold blocks are obtained; the copper and the nickel are electrolyzed out by changing different pH of the solution of the filtrate mainly containing the copper and the nickel and then adding auxiliary agents; and sulfuric acid is added to the rest of the solution to regulate pH, then, reduced pressure distillation is conducted, and ammonium sulfate crystals are prepared. The process is easy to control, the generated dilute nitric acid, the generated sodium nitrate crystals, the generated copper, the generated nickel and the generated gold can all be directly used as products to be sold, the valuable metal, namely, the copper, the nickel and the gold in the waste nitric acid is recycled in a classified manner, and the value maximization of the waste nitric acid is achieved while the resource loss is reduced.

Description

technical field [0001] The invention relates to the technical field of waste water treatment, in particular to a method for classifying and recovering copper, nickel and gold valuable metals in waste nitric acid. Background technique [0002] Waste nitric acid belongs to hazardous waste, which is unstable in nature, strong oxidizing, strong corrosive, strong irritant, can cause burns to the human body, can explode with various substances, and cause combustion and emission when it contacts with reducing agents and combustibles. It emits highly toxic brown smoke and can pollute water bodies and soil. [0003] Waste nitric acid mainly comes from the electroplating industry. At present, the main disposal method for waste nitric acid containing copper, nickel, and gold is to recover dilute nitric acid by vacuum distillation first, then add sodium hydroxide to neutralize the remaining mother liquor and press filter, distill the filtrate to make sodium nitrate, and subcontract the...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22B7/00C22B11/00C22B15/00C22B23/00C25C1/12C25C1/08
CPCC22B7/006C22B11/042C22B15/0089C22B23/0461C25C1/08C25C1/12Y02P10/20
Inventor 胡单钊现花方稳周欢欢
Owner 盛隆资源再生(无锡)有限公司
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