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A recovery method of tin in tin-stripping waste liquid

A recovery method and technology for waste liquid, applied in the direction of improving process efficiency, can solve problems such as long reaction time, harsh reaction conditions, high temperature and high pressure, etc., and achieve good environmental and social benefits, low production equipment requirements, and low production costs. Effect

Active Publication Date: 2009-09-16
SHENZHEN SHENTOU ENVIRONMENT TECH CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although reported in the literature based on electrolytic regeneration (seeing US 6,290,835 B1, US 6,685,820 B2, CN1472362A), solvent extraction, regeneration treatment methods such as membrane technology or utilize the method (referring to CN1530466A, CN1569644A) of tin stripping waste liquid to prepare inorganic chemical products , but due to problems such as production costs, its application is limited, and the traditional treatment method resources are not fully utilized, and it is difficult to completely treat wastewater
[0003] In industry, SnO 2 There are mainly two kinds of production methods in China, which are fire method (gasification method) and wet method (nitric acid oxidation method). The tin raw material used is refined tin or high-purity tin (see CN1657417A). Larger, the latter will produce a large amount of nitrogen oxides and waste acid during the production process to be treated
Also there are bibliography to utilize nitric acid, tin tetrachloride, sodium stannate etc. to prepare nano tin dioxide in addition, but reaction conditions are harsh, need to add dispersant, high temperature and high pressure, long reaction time (relevant patents have: CN1121047, CN1657418, CN101108743)

Method used

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  • A recovery method of tin in tin-stripping waste liquid
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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042] Take 1L of tin stripping waste liquid from manufacturer 1, neutralize it with saturated sodium carbonate solution to pH 3.5, filter, transfer the filter cake to a 2L polytetrafluoroethylene beaker, add water and 166.8 grams of sodium hydroxide, tin and sodium hydroxide The molar ratio is 1:4, the amount of water added is such that the weight ratio of water to the dried filter cake is 2 to 4, boiled for 1 hour, transferred to a 5L beaker, and 2L of water is added (the amount of water added is such that sodium stannate can be fully dissolved), mechanically stirred for 60 minutes, filtered, the filtrate was poured into a plastic reactor, and carbon dioxide was introduced to stir the reaction so that the tin precipitation was complete, filtered, washed, and the filter cake was dried to obtain 170.3g metastannic acid powder, tin The recovery rate was 96%. To judge that the tin precipitation is complete, you can take the filtrate after filtration and continue to pass carbon d...

Embodiment 2

[0046]Take 1L of tin stripping waste liquid from manufacturer 1, neutralize the sodium carbonate solution obtained by filtering after carbon dioxide tin precipitation in Example 1 until the pH is 6-6.5, filter, transfer the filter cake into a 2L polytetrafluoroethylene beaker, add water and 290 gram of sodium hydroxide, the molar ratio of tin to sodium hydroxide is 1:7, the amount of water added is such that the weight ratio of water to the dried filter cake is 2 to 4, boil for 2 hours, transfer to a 5L beaker, add water 2L, mechanically stirred for 30 minutes, filtered, poured the filtrate into a plastic reactor, introduced carbon dioxide and stirred until tin precipitation was complete, filtered, washed, and dried to obtain metastannic acid powder. Calcined at 950° C. for 1 hour to obtain 153 g of white tin dioxide powder, the recovery rate of tin was 97.0%.

[0047] The chemical analysis result of the tin dioxide product that embodiment two makes is as follows table (%):

...

Embodiment 3

[0050] Take 1L of tin stripping waste liquid from manufacturer 3, use Example 2 to neutralize the obtained filtrate after carbon dioxide tin precipitation to pH 9, filter, transfer the filter cake to a 2L polytetrafluoroethylene beaker, add water and 157.3 grams of sodium hydroxide , the molar ratio of tin to sodium hydroxide is 1:9, the amount of water added is to make the weight ratio of water to dry filter cake 2 to 4, boil for 2 hours, transfer to a 5L beaker, add 900ml of water, and mechanically stir for 30 Minutes, filter, pour the filtrate into a plastic reactor, pass through carbon dioxide to stir the reaction until the tin precipitation is complete, filter, wash, dry the filter cake and calcinate at 600°C for 3 hours to obtain 64.2g of white tin dioxide Powder, the recovery rate of tin is 96.2%.

[0051] The chemical analysis result of the tin dioxide product that embodiment three makes is as follows table (%):

[0052] Tin oxide Loss on ignition Hydroc...

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Abstract

The invention relates to a recovery method of tin in tin-stripping waste liquid. The invention includes the following steps: (1) using sodium carbonate solution to neutralize the pH value of the tin-stripping waste liquid to 3.5 to 9.0, filtering; (2) taking the filter cake obtained in step 1, adding water and sodium hydroxide, heating for boiling conversion 1 to 2 hours, wherein, the boiling temperature is 103 DEG C to 115 DEG C, adding water for stirring 30-60 minutes and then filtering, wherein, the dosage of the sodium hydrate makes the molar ratio of the tin and sodium hydrate to be 1:4-1:9 ; (3) fetching the filtrate obtained in step 2, stirring and infusing carbon dioxide in the filtrate until the complete deposition of tin, and then filtering, washing, drying the filter cake to obtain the metastannic acid. The invention has lower requirement for production equipment, friendly environment, and lower production costs; the produced metastannic acid and stannic oxide can satisfy various manufacturing production requirements; the entire production process can achieve the recycling use of materials, zero discharge, good economic, environmental and social benefits.

Description

technical field [0001] The invention relates to a method for recovering tin, in particular to a method for recovering tin in a tin stripping waste liquid. Background technique [0002] Printed circuit board tin stripping waste liquid is an acid waste liquid produced during the production process of printed circuit board (PCB), which contains up to 200-240g / L nitric acid, 100g-150g / L tin, 20-40g / L L copper, iron, and a small amount of polycyclic, heterocyclic and other organic substances. The traditional treatment method is to neutralize with alkali (ammonia, sodium hydroxide, sodium carbonate, etc.) first, then filter, and send the filter cake and tin sludge to the smelter for pyrometallurgy, and then add sulfide to the filtrate to recover copper and then discharge it. Although reported in the literature based on electrolytic regeneration (seeing US 6,290,835 B1, US 6,685,820 B2, CN1472362A), solvent extraction, regeneration treatment methods such as membrane technology or ...

Claims

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Application Information

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IPC IPC(8): C22B25/06C22B7/00
CPCY02P10/20
Inventor 陈志传童张法高东瑞廖蔚峰毛谙章
Owner SHENZHEN SHENTOU ENVIRONMENT TECH CO LTD
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