Preparation method of polyaluminum ferric chloride based on coal gangue

Abstract

According to the preparation method of the polyaluminum ferric chloride based on the coal gangue, the polyaluminum ferric chloride is prepared based on the coal gangue, the reaction conditions of the preparation process flow are mild, and compared with extraction of aluminum from bauxite and then preparation of the polyaluminum ferric chloride, the preparation method does not need complex and high-cost raw materials and is low in preparation cost; according to the present invention, the polyaluminum ferric chloride with the high added value is prepared based on the low-value coal gangue, such that the recycling of the aluminum resource in the coal gangue can be achieved, the obvious environmental benefits are provided, the accumulation of the coal gangue on a large amount of land can be reduced, the land resource can be released, the land pressure can be relieved, the pollution can be reduced, and the ecological environment can be improved.

Description

Technical Field

[0001] This invention relates to the field of coal gangue application technology, and in particular to a method for preparing polyaluminum ferric chloride based on coal gangue. Background Technology

[0002] Polyaluminum ferric chloride (PFLC) is an inorganic composite polymeric flocculant characterized by its non-biological toxicity, large floc formation, rapid settling, and lack of secondary pollution. It exhibits significant advantages in treating low-temperature, low-turbidity, and high-oil-content water. Coal gangue, a solid waste generated during coal mining and washing, not only occupies large amounts of land but also causes environmental pollution due to its long-term stockpiling. Coal gangue contains various mineral components, including high levels of silica, alumina, and iron oxide. Aluminum and iron are essential elements for the preparation of PFLC. Therefore, it is necessary to develop a technology for preparing PFLC based on coal gangue to recycle and utilize it, reducing the land occupation and environmental pollution caused by stockpiling. Summary of the Invention

[0003] Therefore, based on the above background, the present invention provides a method for preparing polyaluminum ferric chloride based on coal gangue.

[0004] The technical solution provided by this invention is as follows:

[0005] A method for preparing polyaluminum ferric chloride based on coal gangue, comprising the following steps:

[0006] ① Grind the coal gangue into powder to obtain coal gangue powder;

[0007] ② After mixing the coal gangue powder prepared in step ①, water, hydrochloric acid, and activator, carry out an acid leaching reaction under stirring conditions to obtain an acid leaching slurry;

[0008] ③ Filter the acid leaching slurry to obtain acid leaching solution and acid leaching solid material;

[0009] ④ After heating the acid leaching solution to 70-80℃, add calcium aluminate and adjust the pH to 1-2 to obtain a neutralized slurry;

[0010] ⑤ Filter the neutralized slurry to obtain neutralized liquid and neutralized solid material. Wash the neutralized solid material with water and collect the first wash liquid.

[0011] ⑥ After combining the neutralizing solution and the first wash solution, add an oxidant and carry out an oxidative polymerization reaction. After the reaction is completed, heat the reaction solution and adjust the pH of the reaction solution to 3-4 to obtain an alkalized slurry.

[0012] ⑦ Filter the alkalized slurry to obtain alkalized liquid and alkalized solid material. Wash the neutralized solid material with water and collect the second wash liquid.

[0013] ⑧ After combining the alkalizing solution and the second washing solution, the resulting solid substance is polyaluminum ferric chloride.

[0014] Furthermore, in step ①, the coal gangue powder is powder that has passed through a 200-mesh sieve.

[0015] Furthermore, the temperature of the acid leaching reaction in step ② is controlled at 70-80℃.

[0016] Further, in step ②, coal gangue powder, water, hydrochloric acid, and activator are mixed at a solid-liquid ratio of 1:(3-4)(g / ml).

[0017] Furthermore, the activator is sodium fluoride, and the amount of the activator is 1-5% of the coal gangue powder.

[0018] Furthermore, the oxidant used in step ⑥ is calcium oxide.

[0019] Furthermore, pressure filtration is used in steps ②, ⑤, and ⑦ respectively.

[0020] Furthermore, step ② uses hydrochloric acid with a concentration of 30%-31%. The beneficial effects achieved by this invention are:

[0021] This invention prepares polyaluminum ferric chloride based on coal gangue. The preparation process has mild reaction conditions. Compared with extracting aluminum from bauxite and then preparing polyaluminum ferric chloride, this invention does not require complex and high-cost raw materials, and the preparation cost is low.

[0022] This invention prepares high-value-added polyaluminum ferric chloride based on low-value coal gangue. It not only realizes the recycling of aluminum resources in coal gangue, but also has significant environmental benefits. This invention can reduce the accumulation of coal gangue on large amounts of land, release land resources, alleviate land pressure, reduce pollution, and improve the ecological environment.

[0023] Instruction manual illustrations

[0024] Figure 1 This is a schematic diagram of the preparation process of polyaluminum ferric chloride in Example 1. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Example 1: A method for preparing polyaluminum ferric chloride based on coal gangue, comprising the following steps:

[0027] ① Grind the coal gangue into powder, and then pass it through a 200-mesh sieve to obtain coal gangue powder;

[0028] The coal gangue in this embodiment originated from a coal mining enterprise in Wuxiang County. Its composition was analyzed, and the results are as follows:

[0029] Al2O3 20%-30%, SiO2 40%-60%, Fe2O3 3%-5%, CaO 1.5-2.52%, MgO 1.5-2.5%, TiO2 0.5-1%, etc. It is clear that Al2O3 and SiO2 have the highest content.

[0030] ② The coal gangue powder prepared in step ①, water, 30% hydrochloric acid solution, and activator (sodium fluoride) are mixed at a solid-liquid ratio of 1:(3-4) (g / ml). Under stirring conditions, the temperature is controlled at 70-80℃ to carry out an acid leaching reaction to obtain an acid leaching slurry. The amount of activator used is 2.5% of the coal gangue powder.

[0031] ③ The acid leaching slurry is filtered to obtain acid leaching liquid and acid leaching solid material; the acid leaching solid material obtained in this step can be used as cement production material.

[0032] ④ After heating the acid leaching solution to 70-80℃, add calcium aluminate and adjust the pH to 1-2 to obtain a neutralized slurry;

[0033] ⑤ The neutralized slurry is filtered to obtain neutralized liquid and neutralized solid material. The neutralized solid material is washed with water and the first wash liquid is collected.

[0034] In practical applications, the neutralized solid material after water washing in this step can be used as a cement production material.

[0035] ⑥ After combining the neutralizing solution and the first wash solution, add the oxidant calcium oxide and carry out the oxidative polymerization reaction. After the reaction is completed, heat the reaction solution and add the alkalizing agent to adjust the pH of the reaction solution to 4 to obtain the alkalized slurry. Calcium oxide ensures the alkalization environment to promote the complexation of aluminum and iron ions.

[0036] ⑦ The alkalized slurry is filtered to obtain alkalized liquid and alkalized solid material. The neutralized solid material is washed with water and the second wash liquid is collected.

[0037] In practical applications, the alkalized solid material after water washing in this step can be used as a cement production material.

[0038] ⑧ After combining the alkalizing solution and the second washing solution, the resulting solid substance is polyaluminum ferric chloride.

[0039] In this step, the alkalizing solution and the second extract can be combined and stored in a buffer tank, and then dried.

[0040] The present invention and its embodiments have been described above. This description is not restrictive, and the embodiments shown are only one of the embodiments of the present invention. The actual structure is not limited to this. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing polyaluminum ferric chloride based on coal gangue, characterized in that, It includes the following steps: ① Grind the coal gangue into powder to obtain coal gangue powder; ② After mixing the coal gangue powder prepared in step ①, water, hydrochloric acid solution, and activator, carry out an acid leaching reaction under stirring conditions to obtain an acid leaching slurry; ③ Filter the acid leaching slurry to obtain acid leaching solution and acid leaching solid material; ④ After heating the acid leaching solution to 70-80℃, add calcium aluminate and adjust the pH to 1-2 to obtain a neutralized slurry; ⑤ Filter the neutralized slurry to obtain neutralized liquid and neutralized solid material. Wash the neutralized solid material with water and collect the first wash liquid. ⑥ After combining the neutralizing solution and the first wash solution, add an oxidant and carry out an oxidative polymerization reaction. After the reaction is completed, heat the reaction solution and adjust the pH of the reaction solution to 3-4 to obtain an alkalized slurry. ⑦ Filter the alkalized slurry to obtain alkalized liquid and alkalized solid material. Wash the neutralized solid material with water and collect the second wash liquid. ⑧ After combining the alkalizing solution and the second washing solution, the resulting solid substance is polyaluminum ferric chloride.

2. The method for preparing polyaluminum ferric chloride based on coal gangue according to claim 1, characterized in that, In step ①, the coal gangue powder is the powder that has passed through a 200-mesh sieve.

3. The method for preparing polyaluminum ferric chloride based on coal gangue according to claim 1, characterized in that, The temperature of the acid leaching reaction in step ② is controlled at 70-80℃.

4. The method for preparing polyaluminum ferric chloride based on coal gangue according to claim 1, characterized in that, In step ②, coal gangue powder, water, hydrochloric acid solution and activator are mixed at a solid-liquid ratio of 1:(3-4)(g / ml).

5. The method for preparing polyaluminum ferric chloride based on coal gangue according to claim 4, characterized in that, The activator is sodium fluoride, and the amount of the activator is 1-5% of the coal gangue powder.

6. The method for preparing polyaluminum ferric chloride based on coal gangue according to claim 1, characterized in that, The oxidant used in step ⑥ is calcium oxide.

7. The method for preparing polyaluminum ferric chloride based on coal gangue according to claim 1, characterized in that, Pressure filtration is used in steps ②, ⑤, and ⑦ respectively.

8. The method for preparing polyaluminum ferric chloride based on coal gangue according to claim 4, characterized in that, Step ② uses hydrochloric acid with a concentration of 30%-31%.

Images