Abstract: Provided is a steam turbine overspeed protection system, includes a drive gear arranged to match a rotation speed of a rotor of a steam turbine; a rotating shaft parallel to an axis of the drive gear and capable of rotating at a critical rotation speed; a protective gear arranged on the rotating shaft and forming a lead screw nut mechanism with the rotating shaft, and arranged to be capable of engaging with the drive gear when the rotation speed of the drive gear exceeds the critical rotation speed; and an operating rod connected to the protective gear; wherein, when the drive gear engages with the protective gear, the protective gear can move in the axial direction of the rotating shaft and thereby drive the operating rod to move and produce an action that activates a protection device for preventing steam turbine overspeed.

Abstract: The present disclosure provides an artificial dam of a distributed coal mine underground reservoir and its constructing method. The artificial dam comprises a support layer (10), an anti-seepage layer (20), and a concrete structure layer (30) that are successively formed in an auxiliary roadway (1) from inside to outside, the concrete structure layer (30) being embedded into a security coal pillar (2) and/or surrounding rock (3) around the auxiliary roadway (1). Because the concrete structure layer (30) is embedded into the security coal pillar (2) and/or the surrounding rock (3) around the auxiliary roadway (1), the artificial dam is combined to the security coal pillar (2) to together form a dam for an underground reservoir. Due to multi-layer design, anti-seepage performance and structural strength of the dam can meet the water storage requirements of the underground reservoir.

Abstract: An opencast coal mine underground water reservoir comprising an impermeable layer and, provided below the impermeable layer, a water storage space and a purification layer. The water storage space comprises a first water storage space and a second water storage space. The purification layer comprises a first purification layer and a second purification layer. The first purification layer is provided horizontally in the water storage space and divides the water storage space into the first water storage space and the second water storage space. The first water storage space is provided below the impermeable layer and between same and the first purification layer. The second water storage space is provided below the first water storage space and the bottom of the second water storage space is provided at the bottom of the opencast coal mine underground water reservoir. The second purification layer is provided vertically within the second water storage space.

Abstract: Disclosed is a method for distributed storage and use of mine groundwater. The method comprises the following steps: A. prospecting an area of an underground space to be mined, and acquiring data on the bedrock geology of the strata; B. observing the mine groundwater, and acquiring the conditions of the flow distribution, water quality data and water pressure data for the mine groundwater; C. designating one or more goaf spaces through which mine groundwater cannot permeate as a water storage space of a distributed underground reservoir according to the data on the bedrock geology of the strata acquired in step A and the conditions of the flow distribution, water quality data and water pressure data for the mine groundwater acquired in step B; and D. after the designated water storage space is formed, mine groundwater generated when mining a mining face adjacent thereto naturally seeps into the water storage space.

Abstract: An opencast coal mine underground water reservoir comprising an impermeable layer and, provided below the impermeable layer, a water storage space and a purification layer. The water storage space comprises a first water storage space and a second water storage space. The purification layer comprises a first purification layer and a second purification layer. The first purification layer is provided horizontally in the water storage space and divides the water storage space into the first water storage space and the second water storage space. The first water storage space is provided below the impermeable layer and between same and the first purification layer. The second water storage space is provided below the first water storage space and the bottom of the second water storage space is provided at the bottom of the opencast coal mine underground water reservoir. The second purification layer is provided vertically within the second water storage space.

Abstract: Disclosed is a method for extracting gallium from fly ash, which comprises the following steps: crushing the fly ash and removing Fe by magnetic separation; then dissolving it by using hydrochloric acid to obtain hydrochloric acid leachate; adsorbing gallium contained in the hydrochloric acid leachate with macro-porous cationic resin, followed by eluting to obtain an eluent containing gallium; adding masking agent to mask ferric ion to obtain an eluent containing gallium after masking; adsorbing gallium in the eluent containing gallium after masking with macro-porous cationic resin, followed by eluting to obtain a secondary eluent; adding sodium hydroxide solution into the secondary eluent to react; filtering and removing precipitates after reaction, and then concentrating the filtrate and electrolyzing to obtain metal gallium. The method simplifies the process and improves extraction efficiency of gallium.

Abstract: Provided a method for preparing metallurgical-grade alumina by using fluidized-bed fly ash, comprising: a) removing iron by wet magnetic separation after crushing the fly ash; b) reacting the fly ash after magnetic separation with hydrochloric acid to obtain a hydrochloric leachate; c) passing the hydrochloric leachate through macro-porous cationic resin to deeply remove iron to obtain a refined aluminum chloride solution; d) concentrating and crystallizing the refined aluminum chloride solution to obtain an aluminum chloride crystal; and e) calcining the aluminum chloride crystal to obtain the metallurgical-grade alumina. The method is simple, the procedure is easy to be controlled, the extraction efficiency of alumina is high, the production coast is low, and the product quality is steady.

Abstract: A vertical ring magnetic separator for de-ironing of coal ash comprises a rotating ring (101), an inductive medium (102), an upper iron yoke (103), a lower iron yoke (104), a magnetic exciting coil (105), a feeding opening (106), a tailing bucket (107) and a water washing device (109). The feeding opening (106) is used for feeding the coal ash to be de-ironed, and the tailing bucket (107) is used for discharging the non-magnetic particles after de-ironing. The upper iron yoke (103) and the lower iron yoke (104) are respectively arranged at the inner and outer sides of the lower portion of the rotating ring (101). The water washing device (109) is arranged above the rotating ring (101). The inductive medium (102) is arranged in the rotating ring (101).

Abstract: Provided a method for preparing metallurgical-grade alumina by using fluidized-bed fly ash, comprising: a) removing iron by wet magnetic separation after crushing the fly ash; b) reacting the fly ash after magnetic separation with hydrochloric acid to obtain a hydrochloric leachate; c) passing the hydrochloric leachate through macro-porous cationic resin to deeply remove iron to obtain a refined aluminum chloride solution; d) concentrating and crystallizing the refined aluminum chloride solution to obtain an aluminum chloride crystal; and e) calcining the aluminum chloride crystal to obtain the metallurgical-grade alumina. The method is simple, the procedure is easy to be controlled, the extraction efficiency of alumina is high, the production coast is low, and the product quality is steady.

Abstract: Disclosed is a method for extracting gallium from fly ash, which comprises the following steps: crushing the fly ash and removing Fe by magnetic separation; then dissolving it by using hydrochloride acid to obtain hydrochloric acid leachate; adsorbing gallium contained in the hydrochloric acid leachate with macro-porous cationic resin, followed by eluting to obtain an eluent containing gallium; adding masking agent to mask ferric ion to obtain an eluent containing gallium after masking; adsorbing gallium in the eluent containing gallium after masking with macro-porous cationic resin, followed by eluting to obtain a secondary eluent; adding sodium hydroxide solution into the secondary eluent to react; filtering and removing precipitates after reaction, and then concentrating the filtrate and electrolyzing to obtain metal gallium. The method simplifies the process and improves extraction efficiency of gallium.

Abstract: Disclosed is a method for extracting gallium from fly ash, which comprises the following steps: crushing the fly ash and removing Fe by magnetic separation; then dissolving it by using hydrochloride acid (2) to obtain hydrochloric acid leachate; adsorbing gallium in the hydrochloric acid leachate with macro-porous cationic resin, followed by eluting to obtain the eluent (5) containing gallium; adding sodium hydroxide (6) solution into the eluent containing gallium to react and obtaining sodium metaaluminate solution containing gallium (8); introducing CO2 into the sodium metaaluminate solution containing gallium (8) for carbonation, followed by separating gallium from aluminum and obtaining aluminum-gallium double salt (15) with the gallium to alumina mass ratio being more than 1:340; adding the aluminum-gallium double salt (15) into sodium hydroxide (17) to react, followed by alkalinity-adjustment concentration to obtain alkali solution containing gallium and aluminum; electrolyzing (10) the alkali solution

Abstract: A vertical ring magnetic separator for de-ironing of coal ash comprises a rotating ring (101), an inductive medium (102), an upper iron yoke (103), a lower iron yoke (104), a magnetic exciting coil (105), a feeding opening (106), a tailing bucket (107) and a water washing device (109). The feeding opening (106) is used for feeding the coal ash to be de-ironed, and the tailing bucket (107) is used for discharging the non-magnetic particles after de-ironing. The upper iron yoke (103) and the lower iron yoke (104) are respectively arranged at the inner and outer sides of the lower portion of the rotating ring (101). The water washing device (109) is arranged above the rotating ring (101). The inductive medium (102) is arranged in the rotating ring (101).