Method for extracting arsenic from pyrite cinder

[0017] Embodiment 1: take a kind of sulfuric acid slag, after analysis, various elements by weight contain iron 57.12%, phosphorus 1.11%, arsenic 1.51%, silicon dioxide 8.22%, magnesium oxide 8.78%, calcium oxide 12.31%, two trioxide Aluminum 4.44%, sulfur 1.32%, lead 1.56%, zinc 2.18%, potassium oxide 1.31%, sodium oxide 0.14%.

[0018] After taking 200g of sulfuric acid slag through a 60-mesh sieve and 800 Gauss magnetic separation, the refined iron powder was taken for chemical separation, and the hydrochloric acid used in the chemical separation was 30% by weight of hydrochloric acid. Add 194ml of water to the refined iron powder to form a slurry, add 6ml of hydrochloric acid to the slurry, stir at normal temperature and pressure for 30 minutes, filter, and separate the solid and liquid; add 188ml of water to the separated refined iron powder, and then add 12ml of hydrochloric acid. After stirring for 30min, filter and wash to separate the solid and liquid; add 180ml of water to the separated refined iron powder, add 20ml of hydrochloric acid, stir at normal temperature and pressure for 30min, filter and wash, and separate the solid from the liquid. Then, 12 g of sulfur dioxide was added to the separated solution to precipitate arsenic trioxide, the grade of which was 97.77%, and the recovery rate of arsenic was 95.44%. Calcium hydroxide is added to the solution after arsenic extraction, and calcium phosphate precipitates.

[0019] Embodiment 2: get the sulfuric acid slag 5t of the same composition as Example 1, after screening through 60 mesh sieves and the magnetic separation of 800 Gauss, the remaining fine iron powder 4.75t carries out chemical separation, and the hydrochloric acid adopted in the chemical separation is that the weight percentage is calculated as 30%. % hydrochloric acid. Add 4.75m of water to 4.75t fine iron powder 3 Form ore pulp, add 0.15m hydrochloric acid to the ore pulp 3 , stirred at normal temperature and pressure for 30 minutes, filtered, and separated the solid and liquid; 4.75m of water was added to the separated refined iron powder 3 After adding hydrochloric acid 0.25m 3 , stirred at normal temperature and pressure for 30min, filtered, washed, and the solid-liquid was separated; 4.5m of water was added to the separated refined iron powder 3 Then add 0.5m hydrochloric acid 3 , stirred for 30min at normal temperature and pressure, filtered and washed, and the solid-liquid was separated. The separated liquid was blown into the air for 30min, and then the gas burned with 45kg of sulfur was blown into the liquid to precipitate the arsenic trioxide, the grade of which was 98.23%, and the recovery rate of arsenic was 96.77%. Lime slurry made of 200 kg of calcium oxide and water was added to the solution after arsenic extraction, and calcium phosphate was precipitated.