TWI396595B - A method for the recycling of tin waste - Google Patents

Description

Method for recycling tin-containing waste

This creation belongs to the field of environmental protection and waste resource recycling technology.

At present, the domestic tin-containing waste resource-reducing manufacturers mainly purchase scrap tin and lead tin slag, and then use liquid alkali to adjust the pH value of the waste stripping tin to produce tin mud cake, and then dry the tin mud cake to produce dry tin oxide. The dried tin oxide is sent to a high-temperature furnace for deoxidation reduction at 1400 to 1600 ° C to reduce it to a tin metal state.

In addition, the domestic patents on the recycling of waste tin resources were found. The names of the Republic of China patents 472030, 553906, 555702, I227217, I281955, and I225107 were all described as "treatment methods for stripping lead liquid waste liquid". The tin, lead and copper in the lead waste liquid are recovered, and the main method is to first oxidize the tin-lead waste liquid to form tin or lead oxide or hydroxide, dissolve it, and then generate it by electrolytic reduction. Metal tin or metal lead.

Based on the above results, it has been found that there is no related patent and technology at home and abroad for the technology of chemically converting tin-containing scrap into stannous chloride products. Therefore, the present invention can provide domestic related industries as valuable tin-metal resources in tin-containing scraps. The basis for recycling.

The IC packaging industry, the printed circuit board industry, the electroplating industry, and the surface treatment industry, etc., are tin-based wastes derived from the tin metal process. Because they contain high amounts of valuable tin resources, if they cannot be recycled, they will cause tin. The waste of resources as a whole is a pity, so in view of this, the present invention is directed to the recycling of valuable tin metal in tin-containing scrap.

The main content of the present invention is that the collected tin-containing waste material is firstly immersed and immersed for 4 hours at room temperature under the condition of a solid (g)/impregnation liquid (ml) ratio of 5N to nitric acid for 4 hours. The lead and zinc impurities in the tin scrap are removed to obtain high purity tin oxide (SnO ₂ ) with a sale value. The obtained tin oxide is further immersed in a solid (g)/immersion liquid (ml) ratio at a ratio of 1/50 of 12 N hydrochloric acid plus a reducing agent at 90 ° C for 5 hours to dissolve the tin oxide in the immersion liquid. In order to obtain a tin-containing immersion liquid. It is then replaced with a zinc sheet to replace the tin in the immersion liquid with a metal tin of a sale value. Then, this replacement metal tin was dissolved by heating at 70 ° C for 2 hours under conditions of a solid (g)/impregnation liquid (ml) ratio of 3 N hydrochloric acid to obtain a stannous chloride-containing solution. Then, the stannous chloride-containing solution is evaporated and crystallized at 90 ° C, and the product obtained after the completion of the crystallization is a high-purity stannous chloride product having a sale value.

The preferred method of the present invention is shown in the first figure. First, the collected tin-containing scrap 1 (the appearance of which is shown in Annex 1) is subjected to a nitric acid impregnation and erosion step 2, and the impregnation and erosion operation conditions are: tin-containing scrap 1 (克)/8N nitric acid (ml)=5/50, immersion time=4 hours, immersion temperature=27°C, nitric acid immersion and erosion 2 steps can remove lead and zinc impurities in tin-containing waste 1 and impregnate by nitric acid. After the step, high-purity tin oxide 4 (the appearance of which is shown in Annex 2) can be obtained. The high-purity tin oxide 4 component is analyzed by Energy Dispersive Spectrometer (EDS) as shown in Annex III, while the lead and zinc-containing impregnating solution 21 can be submitted to qualified recyclers for impregnation waste recovery. Process 3.

Further, the high-purity tin oxide 4 obtained by the nitric acid impregnation and etching 2 is subjected to the 5 steps of the hydrochloric acid impregnation and dissolution, and then the tin oxide is dissolved into the tin-containing impregnation liquid 52, and the impregnation is performed. The operating conditions for dissolution are: high purity tin oxide 4 (g) / 12N hydrochloric acid (ml) = 5/50, and additional reducing agent (such as oxalic acid, tartaric acid, sodium sulfite, hypophosphorous acid), immersion time = 5 hours, immersion temperature = At 90 ° C, the residue 51 produced by further impregnation of 5 by hydrochloric acid can be delivered to a qualified manufacturer for final disposal 6 .

The tin-containing immersion liquid 52 obtained by the 5 steps of hydrochloric acid immersion etching is subjected to a zinc sheet replacement step of 7 to replace the tin in the immersion liquid with the replacement metal tin 9, and the replacement condition is: replacement temperature=27° C., replacement time= 10 minutes, the replacement metal tin 9 obtained by the zinc sheet replacement step 7 is as shown in Annex IV, and the composition of the replacement metal tin 9 is analyzed by Energy Dispersive Spectrometer (EDS) as shown in Annex V. It is to be noted that the replacement liquid 71 obtained by the 7-step replacement by the zinc sheet can be supplied to a qualified recycler for the replacement waste liquid recovery treatment 8.

Further, after replacing the metal tin 9 obtained by replacing the zinc sheet with 7, the hydrochloric acid is dissolved in 10 steps to obtain a stannous chloride-containing solution 101, and the dissolution condition is: replacement metal tin 9 (g) / 12 N hydrochloric acid (ml) = 3 /50, dissolution time = 2 hours, dissolution temperature = 70 ° C, under which conditions the replacement metal tin 9 can be completely dissolved into the stannous chloride-containing solution 101.

After the stannous chloride solution 101 is subjected to the crystallization step 11, the tin in the stannous chloride solution 101 can be 100% crystallization into a high-purity stannous chloride product 12, the appearance of which is shown in Annex 6. The conditions of the crystallization 11 are: heating and crystallization at 90 ° C, and the composition of the high-purity stannous chloride product 12 is analyzed by an Energy Dispersive Spectrometer (EDS) as shown in Annex VII.

In order to make the present invention more expressive and practical, the advantages of the present invention are listed as follows:

1. The invention can recover the valuable tin metal in the tin-containing waste, and reduce the waste of valuable tin metal.

2. The technical result of the present invention can obtain "high-purity tin oxide", "replacement metal tin" and "high-purity stannous chloride" products having market value.

3. The invention can avoid the tin metal in the tin-containing waste polluting the environment and endangering human health.

4. The invention can improve the economic benefit of the regeneration of tin metal resources in domestic tin-containing waste.

5. The invention is safe and progressive.

6. The invention has the use value of the business community and the industry.

The first figure is a flow chart for implementing the "method of recycling tin-containing waste" of the present invention.

1‧‧‧ tin-containing scrap

2‧‧‧Nitrate impregnation and erosion

21‧‧‧ Impregnating solution

3‧‧‧ Waste liquid recycling

4‧‧‧High purity tin oxide

5‧‧‧Hydraulic acid impregnation and erosion

51‧‧‧residue

52‧‧‧ tin-containing impregnating solution

6‧‧‧Final disposal

7‧‧‧Zinc strip replacement

71‧‧‧Replacement fluid

8‧‧‧Replacement waste liquid recycling

9‧‧‧Replacement of tin

10‧‧‧ Hydrochloric acid dissolution

101‧‧‧containing stannous chloride solution

11‧‧ ‧ crystallization

12‧‧‧High purity stannous chloride products

Claims (1)

A method for recycling tin-containing waste resources, the main feature of which is that the collected tin-containing waste is impregnated and dissolved with nitric acid, and the lead and zinc impurities in the tin-containing waste can be removed to obtain a high sales value. Purity tin oxide; and the obtained tin oxide is heated and impregnated with a reducing agent such as oxalic acid, tartaric acid, sodium sulfite, hypophosphorous acid, and tin oxide can be dissolved in the impregnation liquid to obtain a tin-containing impregnation liquid; The tin-containing immersion liquid is replaced by a zinc sheet, and the tin in the immersion liquid is replaced with a replacement metal tin of a sale value; then the replacement metal tin is heated and dissolved with hydrochloric acid to obtain a stannous chloride-containing solution; The product containing the stannous chloride solution is heated and evaporated to crystallization, and the product obtained after the completion of the crystallization is a high-purity stannous chloride product having a sale value.