An example of roasting and arsenic removal process before smelting of tin concentrate in Liuzhou smelter

Posted on

High arsenic soot composition of roasting tin concentrate in fluidized furnace of Liuzhou Smelter 1 . The factory originally used the fire method to produce white arsenic. The smoke was first pressed into an oval cluster. It was naturally dried and placed in a square basket. It was hoisted into a distillation furnace and heated to 60 0 ~ 700 °C The pressure in the furnace is -20 ~ -30 Pa , the distillation is 8h , the arsenic volatilization rate is 80 % ~ 95 %, the output purity is 96 % white arsenic, and the residue contains arsenic 5 % to 8% . However, the arsenic vapor in the distillation workshop exceeded the standard and polluted the environment, so the wet extraction of high quality white arsenic was carried out . November 1987, the Act has been completed on a weekly feeding 50kg Smoke, day 100kg Semi-industrial test of white arsenic, the principle flow is shown in the figure 1 . The chemical composition of the soot used in the semi-industrial test and the phase analysis of arsenic are shown in the table. 2 .

  table 1 The composition of roasting soot in tin concentrate of Liuzhou Smelter

Serial number

As

Sn

Sb

Fe

S

Pb

Zn

1

2

35.94

48.85

8.16

3.71

3.36

4.18

9.45

6.18

1.07

1.02

5.52

4.32

1.12

0.22

Main equipment leaching tank         Jacket heated 500L Enamel reaction tank vacuum filter tray     ¢ 1100mm × ( 600 + 100 ) mm
     Neutralization slot         Specifications are the same as the leaching tank
Ion exchange column     ¢ 200mm × 3000mm There are ¢ 120mm × 3000mm Heating tube. Each column can be loaded 45kg (wet based) resin tube evaporator     Stainless steel welding, heating surface 4m 2 Volume 800L
Cooling crystallization tank     The same centrifugal dewatering machine as the leaching tank     SS-600 type, used for white arsenic crystal dehydration far infrared heating furnace    CB80-18 type oven, automatic temperature control 8 0 °C Main technical conditions for white arsenic crystal drying :
Leaching: two sections of hot water leaching, liquid to solid ratio of 7 : 1 . The slag rate is 66.57% , and the slag composition ( % ) is: 4.81As , 38.19Sn , 3.04Sb , 6.02Pb , 1.65Zn , 13.19Fe .
Purification: Since the leachate PH = 5 , it is close to neutral, so the neutralization is omitted, and only the filtrate is neutralized, and the filtrate is clear. The temperature is controlled to remove the neutralized filtrate through the ion exchange column, followed by decolorization of the activated carbon to ensure the whiteness of the product.
The main technical and economic indicators:
Soot containing arsenic     24.31%       Arsenic leaching rate     85.57%
White arsenic direct yield    73.26%      Total white arsenic recovery    80.03%
    Arsenic balance rate    98.80%
product:
White arsenic contains As 2 O 3 greater than 99% , of which special grade ( As 2 O 3 is greater than 99.5% ) accounts for 78.7%
The comparison of the quality of white arsenic produced by wet method and fire method is listed in the table. 3 .
Figure 1   Principle process for extracting high quality white arsenic from wet process of tin-containing high arsenic dust

 

table 2   Chemical composition of arsenic-containing high-arsenic soot and phase analysis of arsenic

ingredient

As

Sb

Sn

Pb

Zn

Fe

S

SiO 2

%

24.31

2.13

25.17

4.25

1.17

8.67

1.25

4.30

Phase of arsenic

As 2 O 3

As 2 O 3 or arsenate

%

21.06

1.95

ingredient

Ca

Al

Mg

Mn

Cd

C

Bi

Cu

TiO 2

%

1.42

0.42

0.28

0.39

0.065

1.13

0.13

0.05

1.71

Arsenic

Phase category

Arsenic sulfide

Total arsenic

Theoretical leaching rate

%

1.30

24.31

86.63

Table 3   Comparison of the quality of white arsenic produced by wet method and fire method

Craft category

Smoke

Arsenic

/ %

Percentage of products at all levels in the total product / %

Whiteness / %

Leaching residue

Arsenic / %

Premium product

First grade

Second grade product

Third grade

Fourth grade

> 99.5

99.5~99

99~98

98~97

97~95

Wet process

Electric rotary kiln method

Electric arc furnace method

Distillation furnace

24.31

45~57

78.7

4.15

21.30

12.24

 

18.66

 

37.56

 

27.59

80~100

65~85

5 ±

14~17

95%~99% As 2 O 3 (no whiteness and grading data)

92%~95% As 2 O 3 (no whiteness and grading data)

Tower Crane Gear

Tower Crane gear mainly including 19/38/99 teeth gear, bevel gear, Tower Crane Sun Gear, and so on, which are the critical parts of the tower crane reducer. 19 teeth gear and 38 teeth gear are connected with two motor shaft repectively, which are connected with 99 teeth gear. The speed is reduced by the transmission of gears.

Bevel Gear,Tower Crane Sun Gear,Crane Pinion Gear,Tower Crane Transmission Gear,Tower Crane Drive Shaft

SHEN YANG BAOQUAN BUSINESS CO., LTD , https://www.sytoplesstowercrane.com