AU581544B2

AU581544B2 - Separation process

Info

Publication number: AU581544B2
Application number: AU64790/86A
Authority: AU
Inventors: James Alexander Greig; Ronald David Hancock; Derek Lindsay
Original assignee: BP PLC
Current assignee: BP PLC; University of Strathclyde
Priority date: 1985-10-17
Filing date: 1986-10-17
Publication date: 1989-02-23
Anticipated expiration: 2006-10-17
Also published as: BE905617A; AU6479086A; GB8525648D0; WO1987002273A1; JPS63501072A

Description

SEPARATION PROCESS

The present invention relates to mineral separation and more particularly relates to the separation of copper from aqueous metal containing solutions.

For example, zinc generally occurs in the form of its sulphide and concentrates having greater than 50% zinc content may be obtained by flotation. The zinc sulphide is roasted to form zinc oxide which may then be acid leached to give a sulphate liquor. Prior to the zinc being extracted by electro inning, it is desirable to remove copper impurities. This is usually achieved by addition of zinc dust to the liquor which displaces the copper from solution. However, this procedure requires a further filtration step.

It is known in hydrometallurgy to use ion exchange resins to process dilute aqueous solutions. They are relatively stable both chemically and mechanically and do not contaminate the effluent stream. The present invention is directed towards the use of a novel chelate exchange resin which is effective for the separation of copper from aqueous metals containing solutions.

Thus according to the present invention there is provided a process for the selective recovery of copper from an aqueous metal containing solution in which (a) the solution at a pH of 7 or less is contacted with a chelate exchange resin to selectively remove a substantial proportion or all of the copper from the solution onto the resin, the chelate exchange resin comprising a ligand in the form of an amine substituted cyclic compound and a methacrylate substrate, and (b) the selectively removed copper being subsequently separated from the chelate exchange resin by elution or equivalent process_*

The amine substituted cyclic compound ligands may be 2-amino methyl pyridlne (2AMPy) , 2-pyridyl-2-imidazole (PylM), 2-aminomethyl piperidine (AMP) , 2-aminoethyl piperazine (AEP) , 3-aminopropyl-2-piperidine (APP), 3-aminoρropyl morpholine (APM), furfurylamine (FFA), 2-aminobenzo-thiazole (ABT), 2-amino^thiazole (AT), 2-amino-thiophenol (ATP), 2-thiophene carboxylic acid hydrazide (TCAH) or 2-aminoethyl pyridine (2AEPy).

The preferred methacrylate substrate is glycidyl methacrylate.

The invention will now be described by way of example only.

The polystyrene (PS) resins were obtained by standard suspension polymerisation procedures using styrene and divinyl benzene. The resin bead sizes were dependent on the particular procedure used and ranged from 50 to 1000 urn. The PS resins are included for purposes of comparison.

The glycidyl methacrylate (GMA) substrates or resins were prepared by the suspension polymerisation of glycidyl methacrylate and ethylene glycol dimethacrylate with a mixture of cyclohexanol and dodecanol as the porogen. It is preferred to use glycidyl methacrylate and ethylene glycol dimethacrylate (8/2 to 6/4, volume to volume) with a porogen (having a monomer/diluent volume to volume ratio of 1/1 to 1/2). It is preferred that the porogen is a mixture of cyclohexanol and dodecanol having a volume to volume ratio of 9/1.

The ligands were attached to the GMA. resins by reacting resin bound epoxy propyl groups directly with an excess of each ligand.

The extraction of copper ions from acid solutions containing zinc and copper ions was carried out by batch testing and column testing.

In batch testing, 5 ml (wet settled volume-wsv) of the particulate pre-treated resin is contacted with 500 ml of the metal ion solution. The concentration of metal ion was 1000 ppm each and the solution was pH 5. The resin was stirred (about 300 rpm) in a 1 litre container, the apparatus being thermostatted at 25°C. Samples (5 ml) were taken for analysis by atomic absorption spectroscopy (AAS) at intervals of 0, 10, 30, 60, 120, 240 minutes and 24 hours. The extractive capacity of the resin was determined from the difference between the concentrations of the 24 hour sample and the initial feed. Stripping of the extracted ions from the resin was carried out in an analogous manner using 500 mis of 1 M. sulphuric acid as the eluant. All the resins used were pre-treated before extractive use by contacting with 10% ammonium hydroxide for one hour and then by washing to pH 7 with distilled water.

Table 1 shows data on the resins used and Table 2 shows comparative results for GMA and PS resins for batch metals extraction.

TABLE 1 Resin Data

TABLE 2 Batch Extraction Tests on Synthetic Solutions

In single column testing, a column was loaded with 10 ml (wet settled volume) of the pre-treated resin, the resin being supported by a porous frit or plate. A peristaltic pump was used to load the column at an upflow of 10 bed volumes (BV) per hour until break through with a solution containing 700 mg/litre of cupric (Cu²⁺) ions at pH of 5 and 25°C. (The breakthrough was taken as the emergence of 10% of the feed concentration) . Af er washing the column was eluted with sulphuric acid (concentration 100 g/litre) at a flow rate of 10 BV/hour. By collecting the eluant in fractions and analysing for metal content with atomic absorption spectroscopy (AAS), the results shown in Table 3 were obtained.

TABLE 3

Effect of Resin Type on Extraction of Copper from

Synthetic Solutions

Table 4 shows the effect of the presence of cadmium and zinc ions on the extraction of copper ions from solution. Single column testing was used, the column being loaded with 10 ml (wsv) of the pre-treated resin. Three separated feed solutions were passed through GMA and PS resin columns. The solutions contained (a) 400 mg/litre cupric ions (b) 400 mg/litre cupric ions + 800 mg/litre of cadmium (2+) ions and (c) 400 mg/litre of cupric ions + 800 mg/litre of cadmium (2+) ions + 150 g/litre of zinc (2+) ions. The solution temperatures was 25°C, the pH was 5 and the flow rate was 10 BV/hour. No significant amounts of cadmium or zinc ions were extracted by the GMA resins from the respective solutions. TABLE 4 Effect of Cadmium and Zinc on Copper Extraction from Synthetic Solutions

Table 5 shows the results for the extraction of copper ions from solutions by use of two columns of pre-treated GMA resins, the columns being arranged to be in series.

TABLE 5 Extraction of Copper from Synthetic Solution by Two Columns of GMA/2AMPy Resin in Series

The results indicate that GMA/ligand systems are as effective or more effective than PS/ligand systems. The GMA/ligand systems are shown to be particularly effective in extracting copper in the presence of cadmium and cadmium and zinc ions.

Claims

Claims:

1 A process for the selective recovery of copper from an aqueous metal containing solution in which (a) the solution at a pH of 7 or less is contacted with a chelate exchange resin to selectively remove a substantial proportion or all of the copper from the solution onto the resin, the chelate exchange resin comprising a ligand in the form of an amine substituted cyclic compound and a methacrylate based substrate, and (b) the selectively removed copper being subsequently separated from the chelate exchange resin.

2 A process according to claim 1 in which the methacrylate substrate is glycidyl methacrylate.

3 A process according to claim 1 in which the amine substituted cyclic compound is 2-amino methyl pyridine (2AMPy) , 2-pyridyl-2-imidazole (PylM), 2-aminomethyl piperidine (AMP), 2-aminoethyl piperazine (AEP), 3-aminopropyl-2-piρeridine (APP), 3-aminopropyl morpholine (APM), furfurylamine (FFA), 2-aminobenzo-thiazole (ABT), 2-amino-thiazole (AT), 2-amino-thiophenol (ATP), 2-thiophene carboxylic acid hydrazide (TCAH) or 2-aminoethyl pyridine (2AEPy).

4 A process according to any of claims 1 to 3 in which the glycidyl methacrylate substrate is prepared by the suspension polymerisation of glycidyl methacrylate and ethylene glycol dimethacrylate.

5 A process according to claim 4 in which a porogen comprising cyclohexanol and dodecanol is used in the suspension polymerisation.

6 A process according to claim 1 in which the pH of the solution is in the range 2 to 6. 7 A process according to claim 1 in which the copper is subsequently removed from the chelate exchange resin by elution.