Heavy-duty Cnc Stone Carving Machine
welded tubular steel structure
Stainless Steel Water tank
water-cooling constant torque spindles
linear square HIWIN rails on
Applications
Suitable for nature marble, granite, bluestone, sandstone, artifical stone, tombstone, milestone, ceramic tile, jade, crystal, ceramics, glass, plastic, wood, bamboo, cambered surface, sphere, stainless steel, iron, copper, aluminum, titanium, alloy, can doing 3D embossment, and line engraving, beveling, drilling 2D engraving.Such as granite stone can be layered engraving 3mm. Marble, bluestone can be engraving to 3mm on time.
Engraving characters, letters, pattern, intaglio, rilievi, handwriting, ancient calligraphy, abrazine colored drawing, flat carving colored drawing, etc on stone, glass, depth can control optionally, to reach the artistic effect.
Application materials:
Granite, the crystal, marble, stone, all kinds of man-made stone, glass and copper aluminum iron and other hard objects.
Stone Carving Machine,Cnc Stone Carving Machine,Stone Engraving Machine,3D Stone Carving Machine Nanjing Diding Numerical Control Technology Co.,Ltd. , https://www.dinglicncmachine.com
When the carbonaceous gold ore is leached with sodium hypochlorite, it must be oxidized by oxygen in advance to eliminate certain reducing substances. The slurry has a solid-solid ratio of 7:1, sodium carbonate is added to adjust the pH to 8-13, oxygen is passed at 49-98 ° C, oxidized for 4-6 h, then leached with sodium hypochlorite for several hours at a temperature of 20-60 ° C, adsorbed with activated carbon. The gold eluted is recovered and the leaching recovery rate of gold is over 90%.
When leaching gold with a calcium hypochlorite solution under acidic conditions, it is necessary to add an appropriate amount of a chloride complexing agent such as salt. It is slurried with gold mud and acidified to a pH of about 2, and then leached with calcium hypochlorite for several hours, and the gold leaching rate exceeds 95%. The gold in the solution is recovered by solvent extraction.
Magnet containing ore, copper oxide and bound alkaline gangue minerals and mica diopside ammonia leaching copper slag, not acid leaching, reagent consumption as much. Leaching with sodium hypochlorite under alkaline conditions, the gold leaching rate is 92%. Since the copper slag contains residual ammonia, it strongly infiltrates with silver to form silver ammine complex ions into the solution, and the leaching rate of silver reaches 76%. The thermodynamic data of gold dissolution indicated that when the pH of the system was greater than 9.7, the dissolved gold was hydrolyzed to precipitate Au(OH) 3 or AuO 2 . Although ammonia in the slurry is beneficial for silver leaching, it is necessary to control the pH of the system to be no higher than 9.7 to ensure a high gold leaching rate. NaClO and C1 - are both leaching agents, oxidizing agents and complexing agents. Therefore, maintaining a certain concentration of chloride ions, the reactants form complex anions, which can improve the solubility of gold, eliminate passivation, and accelerate the dissolution reaction.
Sodium hypochlorite is easily decomposed by heat:
3NaC1O ==== 2NaCl+NaClO 3
Therefore, the leaching temperature should not be too high, preferably 45-50 ° C.
The refractory copper oxide ammonia leaching residue in a certain place in China contains 8.37g/t of gold and 21g/t of silver. Leaching with NaC10 with a mass concentration of 8.4g/L and NaCl with a mass fraction of 8%, the leaching slurry has a solid ratio of 3:1, the system pH is 9.7, the leaching temperature is 53°C, and the leaching time is 7.5h. Au 0.27g/t, Ag5g/t, gold and silver leaching rates were 96.7% and 76.2%, respectively. Part of the leaching solution is supplemented with an appropriate amount of leaching agent to return to the ammonia leaching copper slag, which is suitable for multi-stage countercurrent leaching.
Water chlorination method for gold extraction - hypochlorite leaching process
The leaching process of sodium hypochlorite solution is an alkali leaching process and is also an alkali chlorination process. ClO - / Cl - electrode reduction potential of 1.715 V, higher than that of gold "E (Au + /Au)=1.58V" and Silver [E (Ag + /Ag)=0.80V "and other precious metals, it may be used to leach the ore from Gold and silver. From the potential-pH diagram (see related graph), the potential of HC10 and ClO - is higher than that of Au in all pH ranges, and gold can be leached with sodium hypochlorite solution.