Method of purifying sodium bromide from waste circuit boards pyrolysis coke

Abstract

A method for purifying sodium bromide by the waste circuit board pyrolysis coke, belonging to the field of purifying sodium bromide and high-value utilization, and more particularly, relating to a method for reducing and purifying crude bromine salt enriched from waste circuit board smelting ash by using waste circuit boards pyrolysis coke. The main steps are as follows: carbonization conversion, purification filtration and vacuum exsolution. The pure sodium bromide crystal was obtained by reducing crude bromine salt enriched from waste circuit board smelting ash by using coke in waste circuit board pyrolysis residues, realizing the resource coupling and high-value utilization of the two wastes, avoiding the secondary pollution in the process of recycling the waste circuit boards. It has the characteristics of simple operation, high resource utilization rate and no tail liquid discharge.

Claims

1. A method for purifying sodium bromide from waste circuit board pyrolysis coke, characterized by the following specific steps: (1) carbonization conversion: crude bromine salt enriched from waste circuit board smelting ash is mixed with coke separated from waste circuit board pyrolysis residues to form a uniform mixture, the uniform mixture is heated to obtain carbon monoxide and crude sodium bromide, the carbon monoxide is collected and used as raw material of water gas, in which a mass of the coke is 0.1-1.0 kg per kilogram of the crude bromine salt, reaction temperature is 250-450° C., and reaction time is 1.0-2.0 h; (2) purification filtration: the crude sodium bromide obtained in step (1) is added to distilled water for purification filtration to obtain impurity residues and sodium bromide solution, the impurity residues are centralizedly treated; (3) vacuum exsolution: the sodium bromide solution obtained in step (2) is treated by vacuum exsolution to obtain sodium bromide crystal and exsolution mother liquor, and the exsolution mother liquor is returned to purification filtration process.

2. A method for purifying sodium bromide from waste circuit board pyrolysis coke according to claim 1, characterized in that, in the process of purification filtration, a liquid-solid volume mass ratio is 8:1-3:1 (L/kg), reaction temperature is 50-80° C., and reaction time is 20 -60 min.

3. A method for purifying sodium bromide from waste circuit board pyrolysis coke according to claim 1, characterized in that, in the process of vacuum exsolution, reaction time is 30-60 min and reaction temperature is 60-150° C.

Description

DESCRIPTION OF DRAWINGS

[0014] FIG. 1 shows the process flow diagram of enriching crude bromine salt from waste circuit board smelting ash.

[0015] FIG. 2 shows the process flow diagram of separating waste circuit board pyrolysis coke.

[0016] FIG. 3 shows the process flow diagram of purifying sodium bromide from waste circuit board pyrolysis coke.

EXEMPLARY EMBODIMENTS

[0017] The following exemplary embodiments are intended to further illustrate the invention rather than limit it.

[0018] Exemplary Embodiment 1

[0019] The recovery steps are as follows:

[0020] (1) Carbonization conversion: the crude bromine salt enriched from the waste circuit board smelting ash is mixed with the coke separated from the waste circuit board pyrolysis residues. The uniform mixture is heated to obtain carbon monoxide and crude sodium bromide. Carbon monoxide is collected and used as raw material of water gas, in which the mass of coke is 0.1 kg per kilogram of crude bromine salt, the reaction temperature is 250° C., and the reaction time is 1.0 h;

[0021] (2) Purification filtration: the crude sodium bromide obtained in step (1) is added to distilled water for purification filtration to obtain impurity residues and sodium bromide solution. The impurity residues are centralizedly treated, in which the liquid-solid volume mass ratio is 8:1 (L/kg), the reaction temperature is 50° C., and the reaction time is 20 min;

[0022] (3) Vacuum exsolution: the sodium bromide solution obtained in step (2) is treated by vacuum exsolution to obtain sodium bromide crystal and exsolution mother liquor, and the exsolution mother liquor is returned to the purification filtration process, in which the reaction time is 60min and the reaction temperature is 60° C.

[0023] The purity of the obtained sodium bromide crystal is 98.6%, which meets the standard of the first grade sodium bromide (NaBr≥98.5%) in the standard HG/T 3809-2006 of State Ministry of Chemical Industry.

[0024] Exemplary Embodiment 2

[0025] The recovery steps are as follows:

[0026] (1) Carbonization conversion: the crude bromine salt enriched from the waste circuit board smelting ash is mixed with the coke separated from the waste circuit board pyrolysis residues. The uniform mixture is heated to obtain carbon monoxide and crude sodium bromide. Carbon monoxide is collected and used as raw material of water gas, in which the mass of coke is 1.0 kg per kilogram of crude bromine salt, the reaction temperature is 450° C., and the reaction time is 2.0 h;

[0027] (2) Purification filtration: the crude sodium bromide obtained in step (1) is added to distilled water for purification filtration to obtain impurity residues and sodium bromide solution. The impurity residue are centralizedly treated, in which the liquid-solid volume mass ratio is 3:1 (L/kg), the reaction temperature is 80° C., and the reaction time is 60 min;

[0028] (3) Vacuum exsolution: the sodium bromide solution obtained in step (2) is treated by vacuum exsolution to obtain sodium bromide crystal and exsolution mother liquor, and the exsolution mother liquor is returned to the purification filtration process, in which the reaction time is 30 min and the reaction temperature is 150° C.

[0029] The purity of the obtained sodium bromide crystal is 99.4%, which meets the standard of the superior product sodium bromide (NaBr≥99%) in the standard HG/T 3809-2006 of State Ministry of Chemical Industry.

[0030] Exemplary Embodiment 3

[0031] The recovery steps are as follows:

[0032] (1) Carbonization conversion: the crude bromine salt enriched from the waste circuit board smelting ash is mixed with the coke separated from the waste circuit board pyrolysis residues. The uniform mixture is heated to obtain carbon monoxide and crude sodium bromide. Carbon monoxide is collected and used as raw material of water gas, in which the mass of coke is 0.4 kg per kilogram of crude bromine salt, the reaction temperature is 300° C., and the reaction time is 1.2 h;

[0033] (2) Purification filtration: the crude sodium bromide obtained in step (1) is added to distilled water for purification filtration to obtain impurity residues and sodium bromide solution. The impurity residues are centralizedly treated, in which the liquid-solid volume mass ratio is 7:1 (L/kg), the reaction temperature is 60° C., and the reaction time is 25 min;

[0034] (3) Vacuum exsolution: the sodium bromide solution obtained in step (2) is treated by vacuum exsolution to obtain sodium bromide crystal and exsolution mother liquor, and the exsolution mother liquor is returned to the purification filtration process, in which the reaction time is 50 min and the reaction temperature is 100° C.

[0035] The purity of the obtained sodium bromide crystal is 98.8%, which meets the standard of the first grade sodium bromide (NaBr≥98.5%) in the standard HG/T 3809-2006 of State Ministry of Chemical Industry.

[0036] Exemplary Embodiment 4

[0037] The recovery steps are as follows:

[0038] (1) Carbonization conversion: the crude bromine salt enriched from the waste circuit board smelting ash is mixed with the coke separated from the waste circuit board pyrolysis residues. The uniform mixture is heated to obtain carbon monoxide and crude sodium bromide. Carbon monoxide is collected and used as raw material of water gas, in which the mass of coke is 0.8 kg per kilogram of crude bromine salt, the reaction temperature is 400° C., and the reaction time is 1.8 h;

[0039] (2) Purification filtration: the crude sodium bromide obtained in step (1) is added to distilled water for purification filtration to obtain impurity residues and sodium bromide solution. The impurity residues are centralizedly treated, in which the liquid-solid volume mass ratio is 6:1 (L/kg), the reaction temperature is 75° C., and the reaction time is 50 min;

[0040] (3) Vacuum exsolution: the sodium bromide solution obtained in step (2) is treated by vacuum exsolution to obtain sodium bromide crystal and exsolution mother liquor, and the exsolution mother liquor is returned to the purification filtration process, in which the reaction time is 40 min and the reaction temperature is 130° C. The purity of the obtained sodium bromide crystal is 99.2%, which meets the standard of the superior product sodium bromide (NaBr≥99%) in the standard HG/T 3809-2006 of State Ministry of Chemical Industry.

[0041] Exemplary Embodiment 5

[0042] The recovery steps are as follows:

[0043] (1) Carbonization conversion: the crude bromine salt enriched from the waste circuit board smelting ash is mixed with the coke separated from the waste circuit board pyrolysis residues. The uniform mixture is heated to obtain carbon monoxide and crude sodium bromide. Carbon monoxide is collected and used as raw material of water gas, in which the mass of coke is 0.5 kg per kilogram of crude bromine salt, the reaction temperature is 350° C., and the reaction time is 1.5 h;

[0044] (2) Purification filtration: the crude sodium bromide obtained in step (1) is added to distilled water for purification filtration to obtain impurity residues and sodium bromide solution. The impurity residues are centralizedly treated, in which the liquid-solid volume mass ratio is 4:1 (L/kg), the reaction temperature is 70° C., and the reaction time is 40 min;

[0045] (3) Vacuum exsolution: the sodium bromide solution obtained in step (2) is treated by vacuum exsolution to obtain sodium bromide crystal and exsolution mother liquor, and the exsolution mother liquor is returned to the purification filtration process, in which the reaction time is 45 min and the reaction temperature is 120° C.

[0046] The purity of the obtained sodium bromide crystal is 98.9%, which meets the standard of the first grade sodium bromide (NaBr≥98.5%) in the standard HG/T 3809-2006 of State Ministry of Chemical Industry.

[0047] Exemplary Embodiment 6

[0048] The recovery steps are as follows:

[0049] (1) Carbonization conversion: the crude bromine salt enriched from the waste circuit board smelting ash is mixed with the coke separated from the waste circuit board pyrolysis residues. The uniform mixture is heated to obtain carbon monoxide and crude sodium bromide. Carbon monoxide is collected and used as raw material of water gas, in which the mass of coke is 0.6 kg per kilogram of crude bromine salt, the reaction temperature is 350° C., and the reaction time is 1.6 h;

[0050] (2) Purification filtration: the crude sodium bromide obtained in step (1) is added to distilled water for purification filtration to obtain impurity residues and sodium bromide solution. The impurity residues are centralizedly treated, in which the liquid-solid volume mass ratio is 5:1 (L/kg), the reaction temperature is 70° C., and the reaction time is 45 min;

[0051] (3) Vacuum exsolution: the sodium bromide solution obtained in step (2) is treated by vacuum exsolution to obtain sodium bromide crystal and exsolution mother liquor, and the exsolution mother liquor is returned to the purification filtration process, in which the reaction time is 30min and the reaction temperature is 80° C.

[0052] The purity of the obtained sodium bromide crystal is 99.1%, which meets the standard of the superior product sodium bromide (NaBr≥99.0%) in the standard HG/T 3809-2006 of State Ministry of Chemical Industry. The above embodiments are only used to illustrate the preferred embodiments of the invention, but the invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art and on the premise of not departing from the science and design spirit in the invention, the modifications, equivalent substitutions and improvements et al. made on the spirit and principles of the invention shall be regarded as in the scope of protection of the application.