A method for preparing water purifying agent containing polyaluminum chloride from aluminum ash

Abstract

The invention provides a method for preparing a water purifying agent containing polyaluminum chloride from aluminum ash, comprising the following steps: roasting aluminum ash, calcium carbonate and / or calcium oxide in an oxidizing atmosphere; roasting the resulting material, and reacting it with hydrochloric acid to prepare The water purifying agent containing polyaluminum chloride, and the solid residue obtained by washing the filter residue with water can be used for other purposes or stored or landfilled. The method of the present invention oxidizes aluminum contained in aluminum ash to alumina, oxidizes contained aluminum nitride to alumina and nitrogen, and reacts alumina with low reactivity to generate calcium aluminate for activation, thereby solving the problem of hydrolysis of metallic aluminum or acid Liberate the flammable and explosive problem of hydrogen, and the ammonium nitrogen problem in the purified water caused by the hydrolysis of aluminum nitride to produce ammonium into the water purifier; and further prepared polyaluminum chloride water purifier and polyaluminum chloride iron composite water purifier; its The process is simplified, the investment and operating costs are low, and the filter residue produced is general solid waste.

Description

technical field

[0001] The invention belongs to the technical field of nonferrous metallurgy and environmental protection, and in particular relates to a method for preparing a water purifying agent containing polyaluminum chloride from aluminum ash. Background technique

[0002] Aluminum ash is an important solid waste in the aluminum industry. According to different sources and metal aluminum content, it is generally divided into primary aluminum ash and secondary aluminum ash; in addition to metal aluminum, aluminum ash generally also contains sodium chloride, potassium chloride, Fluoride salts, alumina, aluminum nitride. Primary aluminum ash has a relatively high metal aluminum content, and metal aluminum is usually recovered by methods such as salt bath treatment. Secondary aluminum ash includes the residue after recycling metal aluminum from primary aluminum ash, and its metal aluminum content is lower than that of primary aluminum ash; secondary aluminum ash can also...

Examples

Embodiment 1

[0040] Prepare the water purifying agent containing polyaluminum chloride as follows:

[0041] A. Take a secondary aluminum ash M1000kg (-10 mesh, see Table 1 for chemical composition) and limestone H800kg (-8 mesh, see Table 1 for chemical composition) and put it into a ball mill, mix ball mill for 5hr to -100 mesh, and the powder after grinding Calcined at 950°C for 3 hours in an oxidizing atmosphere of a small rotary kiln to obtain a roasted product;

[0042] B. In the 5000L reaction tank, add 3200kg of 20m% hydrochloric acid, start stirring, gradually put in slightly warm roasted raw material for reaction, gradually add 1600L of tap water, gradually increase the temperature of the slurry to 85°C, then control the temperature at 85-90°C, before overheating Appropriately reduce the temperature and feeding speed of the roasted raw material, the reaction time is 1.5hr, until the pH of the slurry filtrate is 3.8, Al 2 o 3 6.1m%, basicity 52;

[0043] C. The slurry in step B ...

Embodiment 2

[0048]Basically repeat the steps of Example 1 to prepare the water purifying agent containing polyaluminum chloride, the difference is that the ground powder in step A is roasted at 900°C in a small rotary kiln to obtain the roasted product; the tap water supplemented in step B slurry is replaced with Example 1 1600 L of washing water collected in step C washing the filter residue with water.

[0049] The roasted product obtained in the detection step A no longer contains metallic aluminum, aluminum nitride and calcium carbonate.

[0050] In the reaction of step B, the concentration and quantity of hydrochloric acid added, the amount of material charged by roasting, the control range of slurry temperature, and the reaction time are all the same, and the pH of the slurry filtrate is 3.6, and the Al 2 o 3 5.9m%, basicity 54; calculation of Al in the roasted raw material 2 o 3 The dissolution rate is 76%.

Embodiment 3

[0052] Basically repeat the steps of Example 1 to prepare the water purifying agent containing polyaluminium chloride, the difference is that the powder after step A is roasted in a small rotary kiln at 1000°C to obtain the roasted raw material; the supplemented tap water in step B is replaced by the step of Example 2 C filter residue washing water 1600L collected.

[0053] The roasted product obtained in the detection step A no longer contains metallic aluminum, aluminum nitride and calcium carbonate.

[0054] In the reaction of step B, the concentration and quantity of hydrochloric acid added, the amount of material charged by roasting, the control range of the temperature of the slurry, and the reaction time are all the same, and the pH of the slurry filtrate is 3.9, and the Al 2 o 3 6.2m%, basicity 51; calculation of Al in roasted raw materials 2 o 3 The dissolution rate is 81%.

technical field

[0001] The invention belongs to the technical field of nonferrous metallurgy and environmental protection, and in particular relates to a method for preparing a water purifying agent containing polyaluminum chloride from aluminum ash. Background technique

[0002] Aluminum ash is an important solid waste in the aluminum industry. According to different sources and metal aluminum content, it is generally divided into primary aluminum ash and secondary aluminum ash; in addition to metal aluminum, aluminum ash generally also contains sodium chloride, potassium chloride, Fluoride salts, alumina, aluminum nitride. Primary aluminum ash has a relatively high metal aluminum content, and metal aluminum is usually recovered by methods such as salt bath treatment. Secondary aluminum ash includes the residue after recycling metal aluminum from primary aluminum ash, and its metal aluminum content is lower than that of primary aluminum ash; secondary aluminum ash can also...

Examples

Embodiment 1

[0040] Prepare the water purifying agent containing polyaluminum chloride as follows:

[0041] A. Take a secondary aluminum ash M1000kg (-10 mesh, see Table 1 for chemical composition) and limestone H800kg (-8 mesh, see Table 1 for chemical composition) and put it into a ball mill, mix ball mill for 5hr to -100 mesh, and the powder after grinding Calcined at 950°C for 3 hours in an oxidizing atmosphere of a small rotary kiln to obtain a roasted product;

[0042] B. In the 5000L reaction tank, add 3200kg of 20m% hydrochloric acid, start stirring, gradually put in slightly warm roasted raw material for reaction, gradually add 1600L of tap water, gradually increase the temperature of the slurry to 85°C, then control the temperature at 85-90°C, before overheating Appropriately reduce the temperature and feeding speed of the roasted raw material, the reaction time is 1.5hr, until the pH of the slurry filtrate is 3.8, Al 2 o 3 6.1m%, basicity 52;

[0043] C. The slurry in step B ...

Embodiment 2

[0048]Basically repeat the steps of Example 1 to prepare the water purifying agent containing polyaluminum chloride, the difference is that the ground powder in step A is roasted at 900°C in a small rotary kiln to obtain the roasted product; the tap water supplemented in step B slurry is replaced with Example 1 1600 L of washing water collected in step C washing the filter residue with water.

[0049] The roasted product obtained in the detection step A no longer contains metallic aluminum, aluminum nitride and calcium carbonate.

[0050] In the reaction of step B, the concentration and quantity of hydrochloric acid added, the amount of material charged by roasting, the control range of slurry temperature, and the reaction time are all the same, and the pH of the slurry filtrate is 3.6, and the Al 2 o 3 5.9m%, basicity 54; calculation of Al in the roasted raw material 2 o 3 The dissolution rate is 76%.

Embodiment 3

[0052] Basically repeat the steps of Example 1 to prepare the water purifying agent containing polyaluminium chloride, the difference is that the powder after step A is roasted in a small rotary kiln at 1000°C to obtain the roasted raw material; the supplemented tap water in step B is replaced by the step of Example 2 C filter residue washing water 1600L collected.

[0053] The roasted product obtained in the detection step A no longer contains metallic aluminum, aluminum nitride and calcium carbonate.

[0054] In the reaction of step B, the concentration and quantity of hydrochloric acid added, the amount of material charged by roasting, the control range of the temperature of the slurry, and the reaction time are all the same, and the pH of the slurry filtrate is 3.9, and the Al 2 o 3 6.2m%, basicity 51; calculation of Al in roasted raw materials 2 o 3 The dissolution rate is 81%.

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