Please help! ! Calculation problems for the silver-bismuth system in the rotary kiln process, diaphragm electrolysis process, and comprehensive process!
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1. Rotary kiln process questions: During this cycle, three batches of material were fed into the rotary kiln. As measured by an 80-ton scale, the weights of these batches were 350 tons, 450 tons, and 500 tons respectively. After baking in the rotary kiln, 995 tons of baked slag, 200 tons of electric dust, 40 tons of arsenic-tin slag, and 20 tons of kiln caking were produced. The composition of each type of material is shown in Table 1. Please prepare a material balance sheet for tin, lead, and arsenic obtained through baking in the rotary kiln during this cycle, determine the direct recovery rates and balance rates for tin and lead, as well as the rates of arsenic and sulfur removal by the rotary kiln. Additionally, analyze the factors that affect the direct recovery rates of these metals and whether a balance is achieved. Table 1: Composition of materials in the rotary kiln (units: %)Material name: Sn, Pb, As, S, Fe, H2O
Material 1: 37.01, 5.27, 10.18, 1.51, 19.04, 3.21
Material 2: 36.63, 6.56, 10.15, 1.5, 17.08, 2.9
Material 3: 38.11, 2.88, 10.08, 1.48, 19.13, 3.5
Burning slag: 40.15, 4.95, 1.83, 0.84, 6.2, –
Electrical soot: 27.21, 4.86, 30.98, 0.039, –, –
Arsenic-tin slag: 0.486, 0.132, 78.25, 0.054, –, –
Kiln scale: 40.81, 6.58, 8.66, 1.27, 12.82 -
2. Diaphragm electrolysis process: In this cycle, 40 t of high-antimony crude tin was used. After melting, 0.75 t of anode dross was removed. The resulting tin was quenched in water to form tin florets, which were then used to create anodes. These anodes, along with 5 t of starting plates containing 99.99% lead, were placed in the cell, after which direct current was applied to carry out diaphragm electrolysis. After electrolysis, the cathode tin was produced; after melting it and removing 1.5 tons of slag from the cathode pot, 29 tons of cathode product were obtained, along with 9 tons of residual tin shavings and 10 tons of tin anode sludge. The composition of the materials used in the diaphragm electrolysis process is shown in Tables 2 and 3. The volume of electrolyte circulating within the entire system is 300 m³. A total of 62 cells were used for constant-pressure electrolysis over a period of 12 days, with an average current of 750 A. Calculate the overall process yield of high-antimony crude tin, current efficiency, tin-lead metal balance ratio, and sludge ratio. And analyze the behavior of indium, iron, copper, silver, antimony, and bismuth during the electrolysis process. Table 2: Changes in the electrolyte before and after electrolysis (g/L)
Material Name: Sn, Pb, As, Cu, Bi, Sb, Ag; Total Acid, Free Acid
Before Electrolysis: 46.82, 18.64, 1.05, 0.0038, 0.0066, 0.0349, 0.0006; 198.98, 146.07
After Electrolysis: 45.94, 17.98, 0.4, 0.0014, 0.0038, 0.0268, 0.0005; 202.34, 148.61
Table 3: Composition of solid materials in membrane electrolysis (unit: %)
Material Name: Sn, Pb, As, Cu, Bi, Sb, Ag, H2O
Crude Solder: 71.41, 15.76, 2.53, 1.48, 1.74, 4.5, 0.14
Anode Starting Sheet: 0, 99.99, 0.0031, 0.0015, 0.0012, 0.0016, 0.001
Cathode Product: 67.85, 32.3, 0.0003, 0.0013, 0.0024, 0.0163, 0.0001
Anode Slag: 53.47, 4.31, 4.81, 2.53, 2.61, 3.88, 0.031
Cathode Slag: 48.58, 28.19, 0.686, 0.029, 0.0143, 0.124, 0.0025
Remaining Solder Flakes: 52.46, 13.20, 3.84, 2.53, 2.22, 5.12, 0.20
Solder Anode Sludge: 38.36, 2.35, 10.23, 4.55, 6.15, 17.18, 0.50, 19.10
Material Name: Sn, Pb, As, Cu, Bi, Sb, Ag; Total Acid, Free Acid
Before Electrolysis: 46.82, 18.64, 1.05, 0.0038, 0.0066, 0.0349, 0.0006; 198.98, 146.07
After Electrolysis: 45.94, 17.98, 0.4, 0.0014, 0.0038, 0.0268, 0.0005; 202.34, 148.61
Table 3: Composition of solid materials in membrane electrolysis (unit: %)
Material Name: Sn, Pb, As, Cu, Bi, Sb, Ag, H2O
Crude Solder: 71.41, 15.76, 2.53, 1.48, 1.74, 4.5, 0.14
Anode Starting Sheet: 0, 99.99, 0.0031, 0.0015, 0.0012, 0.0016, 0.001
Cathode Product: 67.85, 32.3, 0.0003, 0.0013, 0.0024, 0.0163, 0.0001
Anode Slag: 53.47, 4.31, 4.81, 2.53, 2.61, 3.88, 0.031
Cathode Slag: 48.58, 28.19, 0.686, 0.029, 0.0143, 0.124, 0.0025
Remaining Solder Flakes: 52.46, 13.20, 3.84, 2.53, 2.22, 5.12, 0.20
Solder Anode Sludge: 38.36, 2.35, 10.23, 4.55, 6.15, 17.18, 0.50, 19.10
This post was last edited by yn101789 on 2010-12-21 at 18:34. 3. Comprehensive process – silver-bismuth system: Today, 2.36 t of tin anode sludge was leached using hydrochloric acid, resulting in 24 m³ of hydrochloric acid leachate and leaching residue. After lead removal via hot water treatment of the hydrochloric acid leach residue, 318 KG of tin-silver residue was obtained, and after roasting, 176 KG of roasted ore was produced. After dechlorination of the roasted ore, silver was leached using nitric acid, yielding 160 KG of leaching residue (silver-separated residue). Through silver precipitation by chlorination and reduction with ammonium hydrazide, 16 KG of sponge silver was obtained. After dilution and hydrolysis of the hydrochloric acid leachate, 10.20 t of arsenic-antimony slag was obtained; sponge bismuth was produced in an amount of 10.49 t through iron powder displacement, and tin recovery ore amounting to 13.48 t was obtained by neutralizing the liquid resulting from the displacement process with lime. The composition of the materials at each stage is shown in Tables 4 and 5. Calculate the leaching rate of bismuth during leaching with hydrochloric acid, as well as the direct yield of sponge bismuth obtained from tin anode slime. Also determine the silver direct yield for each stage of obtaining sponge silver from the anode slime and for the entire process, and analyze the flow of silver, bismuth, antimony, tin, and lead within this process based on these calculation results. Given the current conditions, is it possible to prepare a metal balance sheet for tin, lead, and silver across the entire process? If possible, please do it ； If not, please analyze the reason. Table 4: Composition of slag materials in the integrated processing process. Material name: Sn, Pb, As, Cu, Bi, Sb, Ag, H2O. Tin anode sludge: 41.70, 1.08, 2.16, 3.90, 20.19, 25.81, 1.40, 15.60. Tin-silver slag: 40.87, 1.03, 1.36, 0.59, 1.74, 7.59, 12.69, 45.64. Silver roasted ore: 39.31, 0.91, 1.67, 12.37. Nitric acid slag: 47.64, 0.83, 1.98, 1.88, 7.44, 3.38, 35.23%. Arsenic-antimony slag: 3.77, 0.85, 5.66, 1.52, 1.17, 70.38, 0.06, 60.36. Sponge bismuth: 0.85, 0.442, 0.68, 10.32, 65.39, 16.35, 0.03, 50.78. Sponge silver: 0.065, 0.002, 0.006, 0.001, 0.072, 97.88, 12.65%. Table 5: Composition of solution materials in the integrated processing process. Material name: Sn, Pb, As, Cu, Bi, Sb, Ag. Hydrochloric acid leachate: 20.21, 0.42, 1.65, 3.15, 15.87, 18.135, 0.0224
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