Device for reducing hexavalent chromium in vanadium extraction wastewater

Abstract

The utility model relates to a device for reducing hexavalent chromium in vanadium extraction wastewater, and belongs to the technical field of vanadium hydrometallurgy equipment. According to the technical scheme, the device comprises a sulfur melting pool (1), a gasification chamber (2), a combustion chamber (3), a cooling chamber (4), an ejector (5), a reaction tank (6), a spray tower (7) and an induced draft fan (8) which are sequentially arranged according to working procedures, medium-pressure steam is introduced into the sulfur melting tank (1) for heating, and molten sulfur is conveyed by adopting a gear pump; air is introduced into the gasification chamber (2) through a primary fan (9) to participate in gasification; air is introduced into the combustion chamber (3) by a secondary fan (10) to support combustion; cooling circulating water is introduced into the cooling chamber for cooling; a hexavalent chromium wastewater pipeline and a sulfur dioxide gas pipeline in the ejector are arranged in a vertically crossed manner; the reaction tank is provided with a liquid discharge pump outlet valve, so that the liquid discharge flow is greater than the liquid inlet flow of the ejector. The device disclosed by the utility model can be used for thoroughly reducing hexavalent chromium in the wastewater into trivalent chromium, so that the production cost is greatly reduced.

Description

Technical Field

[0001] The utility model relates to a device for reducing hexavalent chromium in vanadium extraction wastewater, belonging to the technical field of vanadium hydrometallurgical equipment. Background Art

[0002] In the existing vanadium extraction process using vanadium-titanium magnetite as raw material, vanadium-titanium magnetite is subjected to blast furnace smelting and converter blowing process to obtain chromium-containing vanadium slag. During the sodium roasting and water leaching process of vanadium extraction using vanadium slag as raw material, chromium enters the acidic ammonium salt vanadium precipitation process together with vanadium, and enters the vanadium precipitation supernatant in the form of dichromic acid together with the polyvanadate ions that have not been completely precipitated, i.e. vanadium extraction wastewater, resulting in extremely toxic vanadium precipitation wastewater that cannot be directly discharged. At the same time, chromium is also an important valuable metal element. Therefore, it is of great significance to study the recovery and utilization of valuable metal chromium in vanadium extraction wastewater from high-chromium vanadium slag.

[0003] The traditional process uses sodium metabisulfite to reduce hexavalent chromium in wastewater to generate trivalent chromium and then generate chromium hydroxide precipitate. However, the high unit price of sodium metabisulfite results in high process costs, which in turn increases the cost of wastewater treatment. Utility Model Content

[0004] The utility model aims to provide a device for reducing hexavalent chromium in vanadium extraction wastewater, which reduces the hexavalent chromium in the wastewater to generate trivalent chromium and then generates chromium hydroxide precipitation, has high production efficiency and solves the problems existing in the background technology.

[0005] The technical solution of the utility model is:

[0006] A device for reducing hexavalent chromium in vanadium extraction wastewater, comprising a molten sulfur pool, a gasification chamber, a combustion chamber, a cooling chamber, an ejector, a reaction tank, a spray tower and an induced draft fan arranged in sequence according to the process;

[0007] The molten sulfur pool is heated by medium-pressure steam, and the molten sulfur is transported by a gear pump;

[0008] The gasification chamber is supplied with air by a primary fan to participate in gasification;

[0009] The combustion chamber is supplied with air by a secondary fan to assist combustion;

[0010] The cooling chamber is passed through cooling circulating water for cooling;

[0011] The hexavalent chromium wastewater pipeline and the sulfur dioxide gas pipeline in the ejector are arranged vertically and crosswise;

[0012] The reaction tank is provided with a discharge pump outlet valve so that the discharge flow rate is greater than the injector inlet flow rate.

[0013] Furthermore, the liquid level of the reaction tank is higher than the ejector reaction tail pipe.

[0014] Furthermore, a circulation pump is installed at the bottom of the spray tower to absorb unreacted sulfur dioxide gas using weak alkaline wastewater.

[0015] According to the utility model, after sulfur is melted in the molten sulfur pool, it is gasified in the gasification chamber, and burned in the combustion chamber to generate sulfur dioxide gas, which is cooled in the cooling chamber and then vertically crosses with the wastewater into the ejector. Sulfur dioxide reduces hexavalent chromium in the wastewater to trivalent chromium in the reaction tank, and the reduced wastewater enters the next process, and the excess unreacted sulfur dioxide enters the spray tower for absorption.

[0016] The positive effect of the utility model is that the hexavalent chromium in the wastewater is completely reduced to trivalent chromium by using the device, thereby greatly reducing the production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the equipment assembly of the utility model embodiment;

[0018] In the figure: molten sulfur pool 1, gasification chamber 2, combustion chamber 3, cooling chamber 4, ejector 5, reaction tank 6, spray tower 7, induced draft fan 8. DETAILED DESCRIPTION

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0020] See attached Figure 1 , a device for reducing hexavalent chromium in vanadium extraction wastewater, comprising a molten sulfur pool 1, a gasification chamber 2, a combustion chamber 3, a cooling chamber 4, an ejector 5, a reaction tank 6, a spray tower 7 and an induced draft fan 8 arranged in sequence according to the process;

[0021] The molten sulfur pool 1 is heated by medium-pressure steam, and the molten sulfur is transported by a gear pump;

[0022] The gasification chamber 2 is supplied with air by a primary fan 9 to participate in gasification;

[0023] The combustion chamber 3 is supplied with air by a secondary fan 10 to assist combustion;

[0024] The cooling chamber 4 is passed through cooling circulating water for cooling;

[0025] The hexavalent chromium wastewater pipeline and the sulfur dioxide gas pipeline in the ejector 5 are arranged vertically and crosswise;

[0026] The reaction tank 6 is provided with a discharge pump outlet valve so that the discharge flow rate is greater than the injector inlet flow rate, for example, the discharge flow rate is greater than the injector inlet flow rate by 5-10 m³ / h.

[0027] Furthermore, the liquid level of the reaction tank 6 is higher than the reaction tail pipe of the ejector 5 and is less than 700 mm.

[0028] Furthermore, a circulation pump is installed at the bottom of the spray tower 7 to absorb unreacted sulfur dioxide gas using weak alkaline wastewater.

[0029] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A device for reducing hexavalent chromium in vanadium extraction wastewater, characterized in that: It comprises a molten sulfur pool (1), a gasification chamber (2), a combustion chamber (3), a cooling chamber (4), an ejector (5), a reaction tank (6), a spray tower (7) and an induced draft fan (8) which are arranged in sequence according to the process steps; The molten sulfur pool (1) is heated by medium-pressure steam, and the molten sulfur is transported by a gear pump; The gasification chamber (2) is supplied with air by a primary fan (9) to participate in gasification; The combustion chamber (3) is supplied with air by a secondary fan (10) to assist combustion; The cooling chamber (4) is passed through cooling circulating water for cooling; The hexavalent chromium wastewater pipeline and the sulfur dioxide gas pipeline in the ejector (5) are arranged vertically and crosswise; The reaction tank (6) is provided with a discharge pump outlet valve so that the discharge flow rate is greater than the injector inlet flow rate.

2. A device for reducing hexavalent chromium in vanadium extraction wastewater according to claim 1, characterized in that: The liquid level of the reaction tank (6) is higher than the reaction tail pipe of the ejector (5).

3. A device for reducing hexavalent chromium in vanadium extraction wastewater according to claim 1 or 2, characterized in that: A circulation pump is installed at the bottom of the spray tower (7) to absorb unreacted sulfur dioxide gas using weak alkaline wastewater.

Images