CN106244815A

CN106244815A - A kind of method separating and recovering silver from photographic film

Info

Publication number: CN106244815A
Application number: CN201610788388.5A
Authority: CN
Inventors: 张玉芳; 祝冬霞; 王伟
Original assignee: WUXI ZHONGTIAN SOLID WASTE DISPOSAL Co Ltd
Current assignee: WUXI ZHONGTIAN SOLID WASTE DISPOSAL Co Ltd
Priority date: 2016-08-31
Filing date: 2016-08-31
Publication date: 2016-12-21

Abstract

The invention discloses a kind of method separating and recovering silver from photographic film, the method comprises the steps: the configuration of (1) compound aqueous solution of protease；(2) separation of Silver；(3) reuse containing enzyme filtrate.The inventive method has the advantages such as efficient, easy, treating capacity is big, low expense, environmental protection.

Description

A kind of method separating and recovering silver from photographic film

Technical field

The present invention relates to noble metal recovery technology field, especially relate to one and utilize compound Protease Treatment film system The method taking silver.

Background technology

Silver is widely used in sensitive material industry, is increasingly paid attention to as its recycling of precious metal, photoresists Sheet is mainly used in video display industry, electron trade and medical industry, a large amount of waste films of annual generation, and these waste films contain Silver, chip base is polyethylene terephthalate, has the highest recycling and is worth.

In waste films, silver exists with elemental silver form, is attached in chip base using gelatin as carrier, tradition separate mode bag Include following several big class: 1) burning disposal: by burning disposal, ash reclaims silver, simple to operate, equipment requirements is low, process Amount is big, but the response rate of silver is low, only reaches 75%, secondly can produce a large amount of contaminative flue gas and dust, seriously polluted；It addition, Burning disposal cannot reclaim base material polyester；2) mechanical cleaning method: the Mechanical Method response rate is high, pollution-free, but process rule Mould is little, costly；3) chemical dissolution method: the glutin of macromole become the little molecule of water miscible aminoacid by soda acid, Molecular weight reduces, and water solublity is greatly enhanced, and utilizes the severe corrosive of acid solution and alkali liquor, makes part Ag be transformed into Ag⁺Ion enters Solution film, after nitric acid acidleach, forms silver nitrate solution and reaches to separate purpose, and treating capacity is big, but exists and operate complicated, danger Dangerous big, acid mist pollution serious, produces the shortcomings such as high COD strong acid or highly basic waste liquid.

Summary of the invention

For prior art exist the problems referred to above, the applicant provide a kind of from photographic film separation and recovery silver Method.The inventive method has the advantages such as efficient, easy, treating capacity is big, low expense, environmental protection.

Technical scheme is as follows:

A kind of method separating and recovering silver from photographic film, described method comprises the steps:

(1) configuration of compound aqueous solution of protease: by compound protease 30～50 DEG C successively ultrasonic disperse be dissolved in In aqueous solution, it is configured to the aqueous solution of 5～10wt%；

(2) separation of Silver: first the pH of the compound aqueous solution of protease of regulating step (1) gained is 6～9, and is heated to 40 ～60 DEG C, then photographic film being immersed in this solution, after ultrasonic vibration 8～10h, take out base, silver comes off molten In liquid；

(3) reuse containing enzyme filtrate: by being filtrated to get filtering residue silver powder containing the solution of silver, the pH of filtrate is adjusted again It is 6～9, is re-used for separation of Silver.

Described compound protease is Collagenase, cathepsin, trypsin, the compounding gained of polypeptidase mixing Compound enzyme；Described Collagenase, cathepsin, trypsin, polypeptidase account for the 15～45% of compound enzyme total amount respectively, always With 100%.

Described compound enzyme uses pH to be 6～9, and using temperature is 40～60 DEG C, and scouring processes enters under ultrasonic vibration effect OK.

Described in step (3), filtrate is by utilization repeatable after readjusting pH.

Useful the having the technical effect that of the present invention

The inventive method has treatment conditions gentleness, equipment requirements condition is low, treatment effeciency is high, treating capacity is big, operation is simple The advantages such as clean convenience, processing cost are low, repeatable operation.

First by enzyme treatment technique, process efficiently, use mild condition, according to the repeatable utilization of enzymatic activity, relatively pass System technology has low power consuming, without advantages such as tail washings pollutions.

Secondly, by enzyme degumming separation of Silver, silver has neither part nor lot in chemical reaction, and conventional chemical treatment techniques is all to pass through nitric acid After molten silver, silver is extracted in reduction, and it is high, without acid gas pollution, without advantages such as argentiferous heavy metal wastewater thereby generations that this method has silver raising recovery rate.

Detailed description of the invention

Below in conjunction with embodiment, the present invention is specifically described.

Embodiment 1

Respectively 40mg Collagenase, 30mg cathepsin, 30mg trypsin, 50mg polypeptidase are mixed and be dissolved in In 100mL water, after NaOH regulation pH to 9, it is warming up to 40 DEG C；Photographic film 25g is immersed in ultrasonic vibration 8h in this enzymatic solution After, on film, black part drops, and it is muddy that solution sinks black, removes after base also rinses with clear water and records film silver content Within 0.5mg/g, being filtrated to get black silver pressed powder, silver raising recovery rate reaches 97%；Filtrate repeats profit after readjusting pH With respond well, within reusing number of times 3 times, effect is almost identical, needs to provide soak time extremely when access times 4 times 10h reaches gelatin hydrolysate separating effect.

Embodiment 2

Respectively 400g Collagenase, 300g cathepsin, 300g trypsin, 500g polypeptidase are mixed and be dissolved in In 1t water, after being warming up to 60 DEG C after NaOH regulation pH to 7,250 kilograms of waste photographic films are immersed, open ultrasonic vibration Device after keeping 8h, on film, black part drops, and it is muddy that solution sinks black, removes after base also rinses with clear water and records Film silver content, within 1mg/g, is filtrated to get black silver pressed powder, and silver raising recovery rate reaches 95%；Filtrate readjusts pH Rear recycling is respond well, and within reusing number of times 3 times, effect is almost identical, needs to provide leaching when access times 6 times The bubble time reaches gelatin hydrolysate separating effect to 10h；After adding various enzyme in proportion when access times are more than 6 times, using effect depends on Old well, reach desired target.

Embodiment 3

Respectively 50mg Collagenase, 40mg cathepsin, 200mg trypsin, 45mg polypeptidase are mixed and molten In 100mL water, after NaOH regulation pH to 7, it is warming up to 60 DEG C；Photographic film 25g is immersed in ultrasonic vibration in this enzymatic solution After 8h, on film, black part drops, and it is muddy that solution sinks black, removes after base also rinses with clear water and records film argentiferous Amount, within 0.5mg/g, is filtrated to get black silver pressed powder, and silver raising recovery rate reaches 97%；Filtrate is repeated after readjusting pH Utilizing status is good, and within reusing number of times 3 times, effect is almost identical, needs to provide soak time when access times 6 times Gelatin hydrolysate separating effect is reached to 10h.

Test case:

Fermentoid solution used to embodiment 1 by same ratio 400g Collagenase, 300g cathepsin, The mixing of 300g trypsin, 500g polypeptidase re-uses after adding compound enzyme regulation pH to 9, can reach embodiment 1 phase and exists together Reason effect.Relatively process 10t waste films with nitric acid treatment method this method, water consumption, silver-colored average recovery rate, tailwater quantity, power consumption (with Kw.h counts) contrast.The results are shown in Table 1.

Table 1

Silver recovery method	Water consumption/t	Silver raising recovery rate/%	Tailwater quantity/t	Power consumption/Kw.h
					Nitric acid solution reclaiming method	6	86	5.6 (high COD spent acid)	35
Compound enzyme partition method	2	94	1.8 (high-COD waste waters)	5

Claims

1. the method separating and recovering silver from photographic film, it is characterised in that described method comprises the steps:

(1) configuration of compound aqueous solution of protease: by compound protease 30～50 DEG C successively ultrasonic disperse be dissolved in water-soluble In liquid, it is configured to the aqueous solution of 5～10wt%；

(2) separation of Silver: first the pH of the compound aqueous solution of protease of regulating step (1) gained is 6～9, and is heated to 40～60 DEG C, then photographic film being immersed in this solution, after ultrasonic vibration 8～10h, take out base, silver comes off in the solution；

(3) reuse containing enzyme filtrate: by being filtrated to get filtering residue silver powder containing the solution of silver, the pH of filtrate is adjusted to 6 again ～9, it is re-used for separation of Silver.

Method the most according to claim 1, it is characterised in that described compound protease is Collagenase, histone The compound enzyme of the compounding gained of enzyme, trypsin, polypeptidase mixing；Described Collagenase, cathepsin, trypsin, many Peptidase accounts for the 15～45% of compound enzyme total amount, summation 100% respectively.

Method the most according to claim 1, it is characterised in that described compound enzyme use pH be 6～9, use temperature be 40～ 60 DEG C, scouring processes is carried out under ultrasonic vibration effect.

Method the most according to claim 1, it is characterised in that filtrate described in step (3) is by weighing after readjusting pH Multiple utilization.