A Power Trowel also named power float, helicopter, trowel machine or even a whirlybird,is a kind of light construction equipment used by construction company and building contractors to apply a smooth finish to concrete slabs.
From the using way, the concrete power trowel divided into two types : Walk-behind power trowel and Ride-on Power Trowel Machine.
For the Walk-behind Mini Power Trowel machine,that means an operator is always holding on to and walking behind the machine when it is working. And ride-on power float allows the worker to sit in a seat, they could ride on the machine while controlling the concrete power trowel with the buttons and steering arms.Is more convenient and high efficiency.
Power Trowel Power Trowel,Mini Power Trowel,Power Trowel Machine,Concrete Power Trowel Machine Shandong Hengwang Group Co., Ltd , https://www.hwmac.com
The mine has a processing capacity of 2000t/d. The rough selection includes 800t/d of the original factory and 1200t/d of the expansion. 800t, 1200t rough grinding rough series of coarse concentrates, after entering the graded re-grinding and selection system, the coarse concentrate after a period of re-grinding, 9 selections, 1 sweeping, the final molybdenum grade can reach 45.00 About %, the selected recovery rate is about 73%. The main problems of the system are: 1 complicated operation, high number of selections, long process, which is not conducive to system stability; 2 low flotation efficiency (about 45% of molybdenum concentrate grade) and not stable enough. To improve the operation of molybdenum concentrate grade and recovery aspects of the selection, the mine commissioned China University of Mining in 2000t / d plant for beneficiation by flotation column featured industrial shunt test, and achieved satisfactory sorting effect.
The input of the selected semi-industrial split test is the overflow of the coarse concentrate after classification by the water cyclone, and the final concentrate product is obtained after 3 times of column selection. The semi-industrial split flow of the flotation column selection system is shown in Figure 1. The test results are shown in Table 1. 
Table 1 Selected flotation test results of flotation column
It can be seen from Table 1 that the grade of molybdenum concentrate can be increased to 51.84% by column 3 times, which is 5.49 percentage points higher than that of the flotation machine 9 times and 1 sweep. According to the national standard of molybdenum ore, the grade of molybdenum concentrate products can be improved; the recovery rate is increased to 91.88%, which is 10.08 percentage points higher than the flotation machine process recovery rate.
The above data shows that the column sorting has obvious advantages over the flotation machine process in the sorting of molybdenum ore. 
The ore molybdenum ore is a quartz vein type molybdenum deposit, mainly composed of granite porphyry and Anshan porphyrite structure. Useful mineral molybdenite minerals mainly associated with a magnetic iron ore, iron pyrite, and titanium, and the like; gangue minerals are quartz, feldspar, mica and chlorite; molybdenite ore dissemination size Fine, closely related to gangue minerals, easy to be wrapped in, difficult to separate; in addition, the ore contains a large amount of pyrite, which is easy to float at the same time as the concentrate, which also increases the difficulty of sorting. Therefore, the ore is difficult to select molybdenite.
Figure 1 Swirl-static microbubble column sorting principle
Shift
Flotation column
Flotation machine
Raw ore
Concentrate
Tailings
Recovery rate
Raw ore
Concentrate
Tailings
Recovery rate
1
2
3
4
5
6
average
8.51
7.24
5.36
5.88
6.43
4.74
6.36
52.61
53.06
50.23
51.65
53.87
49.59
51.84
0.672
0.613
0.557
0.542
0.571
0.539
0.582
93.30
92.60
90.61
91.75
92.10
89.60
91.88
9.32
7.15
6.42
5.76
7.47
5.61
6.96
48.07
46.38
45.43
45.89
46.96
45.35
46.35
1.658
1.620
1.451
1.479
1.502
0.951
1.444
85.15
80.14
79.95
76.80
82.53
84.83
81.80