A two-stage grinding and three-stage grinding switching process

Abstract

The invention discloses a two-stage grinding and three-stage grinding switching process, including N first ball mills, each first ball mill matches a first pump pool, a first cyclone, a second pump pool, a second cyclone and a second ball mill, each second ball mill is unidirectionally connected to the fine iron ore through the corresponding first valve, each second ball mill is unidirectionally connected to the same third pump pool through the corresponding second valve, and the third pump pool is unidirectionally connected to the corresponding second pump pool through the third valve; when the two-stage grinding process is carried out, the first valve is opened, the second valve and the third valve are closed, and when the three-stage grinding process is carried out, the first valve and the third valve of the second ball mill selected for the three-stage grinding are opened, the second valve is closed, the first valve and the third valve of the other second ball mills are closed, and the second valve is opened, and the two-stage ball mill is carried out. The present invention does not increase the cost, only switches the two-stage process through valve control, and can be fault-backed up.

Description

Technical Field

[0001] The invention relates to the technical field of grinding technology, in particular to a two-stage grinding and three-stage grinding switching process. Background Art

[0002] As the mines go deeper, most of the ores are difficult to grind and select. In the past, the feed rate of a 5.03*6.4m ball mill could reach 350 tons / hour, and the grinding particle size was about 65%. At this time, the concentrate grade after two-stage magnetic separation could reach more than 55%, which was considered a qualified product. However, now the grinding particle size must reach about 72% to produce iron concentrate with a grade of more than 55%. The grinding particle size becomes finer, resulting in a cliff-like drop in the feed rate of the ball mill to only 200 tons / hour. At the same time, the fineness of the ore particle size also has an adverse effect on the next titanium selection process, because the titanium selection process increases the difficulty of titanium recovery from fine-grained ores, resulting in increased metal loss, which seriously affects titanium recovery. For this reason, the two-stage grinding process is no longer suitable for ores that are difficult to grind and select. Summary of the invention

[0003] The object of the present invention is to provide a two-stage grinding and three-stage grinding switching process to solve the problem that the two-stage grinding process in the prior art is no longer suitable for difficult-to-grind and difficult-to-select ores.

[0004] The present invention solves the above problems through the following technical solutions:

[0005] A two-stage grinding and three-stage grinding switching process, comprising N first ball mills, each of which is matched with a first pump pool, a first cyclone, a second pump pool, a second cyclone and a second ball mill, each of which is unidirectionally connected to the iron ore concentrate through a corresponding first valve, each of which is unidirectionally connected to the same third pump pool through a corresponding second valve, and the third pump pool is unidirectionally connected to the corresponding second pump pool through a third valve;

[0006] When the two-stage grinding process is carried out, the first ball mill, the first pump tank, the first cyclone, the second pump tank, the second cyclone and the second ball mill work together, each first valve is opened, each second valve and the third valve are closed, the first ball mill discharges ore to the first pump tank, and the first slurry pump in the first pump tank is used to pump it to the first cyclone. After classification, the underflow product returns to the first ball mill, and the overflow product flows to the second pump tank by gravity after a first-stage magnetic separation, and is fed into the second cyclone by the second slurry pump in the second pump tank. The second cyclone is classified, and the underflow product after classification flows to the second ball mill. The overflow product flows into the iron concentrate through the first valve after the second-stage magnetic separation;

[0007] When the three-stage grinding process is carried out, the first ball mill, the first pump tank, the first cyclone, the second pump tank, the second cyclone and the second ball mill work together, and one of the second ball mills is arbitrarily selected for the three-stage grinding, the first valve and the third valve corresponding to the second ball mill are opened, the second valve corresponding to the second ball mill is closed, the first valve and the third valve corresponding to the other second ball mills are closed, and the second valves corresponding to the other second ball mills are opened, the first ball mill discharges ore to the first pump tank, and the first slurry pump in the first pump tank is used to pump it to the first cyclone, and the underflow product after classification returns to the first ball mill, and the overflow product flows to the second pump tank by gravity after a first magnetic separation, and is fed into the The second cyclone is used for classification. After the second cyclone corresponding to the selected second ball mill is classified, the underflow product flows to the second ball mill, and the overflow product flows into the iron ore concentrate through the first valve after two-stage magnetic separation; after the second cyclones corresponding to other second ball mills are classified, the underflow product flows to the corresponding second ball mill, and the overflow product flows into the third pump pool through the corresponding second valve after two-stage magnetic separation, and is sent to the second pump pool corresponding to the selected second ball mill through the third valve corresponding to the selected second ball mill by the third slurry pump of the third pump pool, and then the underflow product after classification of the corresponding second cyclone is fed into the selected second ball mill by the second slurry pump in the second pump pool and flows to the selected second ball mill for three-stage ball milling.

[0008] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0009] The present invention adopts the process technology of switching between two-stage grinding and three-stage grinding of the ball mill while maintaining the number of existing ball mills, so that the two-stage grinding is operated when the original ore has good properties and is easy to grind and select, and the three-stage grinding process is operated when the original ore has poor properties and is difficult to grind and select. When a process or equipment failure occurs in a certain series of ball mills, another series of ball mills can be switched in time to continue to organize production without affecting production, thereby ensuring the production operation rate, and the iron selection tailings will not be over-grinded, and the influence on the next titanium selection process is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a principle block diagram of the present invention. DETAILED DESCRIPTION

[0011] The present invention is further described in detail below in conjunction with examples, but the embodiments of the present invention are not limited thereto.

[0012] Example:

[0013] Combined with Figure 1As shown, a two-stage grinding and three-stage grinding switching process, for example, the grinding process of the ore dressing workshop divides six ball mills into three series, each series has two ball mills, namely 1# ball mill→4# ball mill as one series, 2# ball mill→5# ball mill as two series, 3# ball mill→6# ball mill as three series. Previously, it was two-stage grinding, 1#, 2#, 3# ball mills were one-stage ball mills, 4#, 5#, 6# ball mills were two-stage ball mills, and now it has been transformed into a three-stage grinding process, any one of 4#, 5#, 6# ball mills can be used as a three-stage ball mill, and the other two are two-stage ball mills.

[0014] Any one of the 4#, 5#, and 6# ball mills can be switched as a three-stage ball mill to achieve the switch between two-stage grinding and three-stage grinding at any time, including the following processes:

[0015] 1) 4# ball mill rotates in three stages: open valves 4-1, 4-3, 5-2 and 6-2, and close valves 4-2, 5-1, 5-3, 6-1 and 6-3.

[0016] At this time, the 2# and 3# ball mills are operated as the first stage of grinding, and the 5# and 6# ball mills are operated as the second stage of grinding. The coarse concentrate after the second stage of ball grinding is sent to the third stage pump pool through the 5-2 valve and the 6-2 valve respectively, and then pumped to the 4# ball mill by the slurry pump through the 4-3 valve for the third stage of grinding. After magnetic separation, the qualified grade concentrate is directly sent to the next process through the 4-1 valve.

[0017] 2) 5# ball mill rotates in three stages: open valves 4-2, 5-1, 5-3 and 6-2, and close valves 4-1, 4-3, 5-2, 6-1 and 6-3.

[0018] At this time, the 1# and 3# ball mills are operated as the first stage of grinding, and the 4# and 6# ball mills are operated as the second stage of grinding. The coarse concentrate after the second stage of ball grinding is sent to the third stage pump pool through the 4-2 valve and the 6-2 valve respectively, and then pumped to the 5# ball mill through the 5-3 valve by the slurry pump for the third stage of grinding. After magnetic separation, the qualified grade concentrate is directly sent to the next process through the 5-1 valve.

[0019] 3) 6# ball mill rotates to three stages: open valves 4-2, 5-2, 6-1 and 6-3, and close valves 4-1, 4-3, 5-1, 5-3 and 6-2; at this time, operate 1# and 2# ball mills as the first stage of grinding, and 4# and 5# ball mills as the second stage of grinding. The coarse concentrate after the second stage of ball milling is sent to the third stage pump pool through valves 4-2 and 5-2 respectively, and then pumped to 6# ball mill by slurry pump through valve 6-3 for third stage grinding. After magnetic separation, the concentrate with qualified grade is directly sent to the next process through valve 6-1.

[0020] When running two-stage ball mills: the 4-1 valve of the 4# ball mill is open, the 4-2 valve and the 4-3 valve are closed, the 5-1 valve of the 5# ball mill is open, the 5-2 valve and the 5-3 valve are closed, the 6-1 valve of the 6# ball mill is open, the 6-2 valve and the 6-3 valve are closed. At this time, the 1#, 2#, and 3# ball mills are operated as the first stage of grinding, and the coarse concentrates from magnetic separation are sent to the corresponding 4#, 5#, and 6# ball mills for second stage ball milling. After the second stage of ball milling, the concentrates with a grade of 55% from magnetic separation are qualified concentrates, which are directly sent to the next process through the 4-1 valve, the 5-1 valve, and the 6-1 valve.

[0021] Through the implementation of this process, the ore processing capacity of the first-stage ball mill has been increased from the original 847 tons / hour to the current 1,000 tons / hour, as shown in Table 1.

[0022] Table 1 Production test results

[0023]

[0024] The invention is simple to operate. The two-stage grinding process and the three-stage grinding process can be switched mutually by opening and closing the corresponding valves without stopping the machine, and any one of the 4#, 5# and 6# ball mills can be designated as the three-stage ball mill.

[0025] Although the present invention is described herein with reference to the illustrative embodiments of the present invention, the above embodiments are only preferred embodiments of the present invention, and the embodiments of the present invention are not limited to the above embodiments. It should be understood that those skilled in the art can design many other modifications and embodiments, which will fall within the scope and spirit of the principles disclosed in this application.

Claims

1. A two-stage grinding and three-stage grinding switching process, characterized in that: It comprises N first ball mills, each of which is matched with a first pump pool, a first cyclone, a second pump pool, a second cyclone and a second ball mill, each of which is connected to the iron ore concentrate in one direction through a corresponding first valve, each of which is connected to the same third pump pool in one direction through a corresponding second valve, and the third pump pool is connected to the corresponding second pump pool in one direction through a third valve; When the two-stage grinding process is carried out, the first valve is opened, the second valve and the third valve are closed, the first ball mill discharges ore to the first pump pool, and the first slurry pump in the first pump pool is used to pump it to the first cyclone. After classification, the underflow product returns to the first ball mill, and the overflow product flows to the second pump pool by gravity after the first stage of magnetic separation, and is fed into the second cyclone by the second slurry pump in the second pump pool. The second cyclone is classified, and the underflow product after classification flows to the second ball mill. The overflow product flows into the iron concentrate through the first valve after the second stage of magnetic separation; When the three-stage grinding process is carried out, a second ball mill is arbitrarily selected for the three-stage grinding, the first valve and the third valve corresponding to the second ball mill are opened, the second valve corresponding to the second ball mill is closed, the first valve and the third valve corresponding to other second ball mills are closed, and the second valve is opened; the first ball mill discharges ore to the first pump pool, and the first slurry pump in the first pump pool is used to pump it to the first cyclone, and the underflow product after classification returns to the first ball mill, and the overflow product flows to the second pump pool by gravity after a magnetic separation, and is fed into the second cyclone by the second slurry pump in the second pump pool, and the second cyclone is classified. After the corresponding second cyclone classification, the underflow product flows to the second ball mill, and the overflow product flows into the iron ore concentrate through the first valve after two-stage magnetic separation; after the second cyclone classification corresponding to other second ball mills, the underflow product flows to the corresponding second ball mill, and the overflow product flows into the third pump pool through the corresponding second valve after two-stage magnetic separation, and is sent to the second pump pool corresponding to the selected second ball mill through the third slurry pump of the third pump pool and the third valve corresponding to the selected second ball mill, and then the second slurry pump in the second pump pool is used to feed the underflow product after the corresponding second cyclone classification to the selected second ball mill for three-stage ball milling.

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