Method for resource utilization of pineapple peel and electrolytic manganese anode slime

Abstract

The invention provides a new method for resource utilization of pineapple peels and electrolytic manganese anode slime. The method comprises the following basic steps: (1) adding manganese anode slime into a reactor, adding pineapple peels with a mass which is 0.18 to 0.30 time of the mass of manganese anode slime and concentrated sulfuric acid with a mass which is 1.8 to 2.5 times of the mass of manganese anode slime, and regulating liquid-to-solid ratio to 3:1 to 5:1; (2) performing reaction at 90 to 98 DEG C for 4 to 8 hours, wherein the leaching rate of manganese reaches more than 95 percent; (3) obtaining residues with lead content of 46 percent, which can be used as lead concentrate; (4) adding 0.4 to 1.0 g / L waste iron scrap in filtrate, adding activated carbon according to iron-to-carbon mass ratio of 2:1 to 4:1 and performing reaction for 30 to 180mins under an agitating condition at 30 to 98 DEG C, wherein selenium is deposited in a solid phase and the recovery rate of selenium reaches 95 percent; (5) performing filtration again and then returning back filtrate for producing electrolytic manganese. The method for resource utilization of pineapple peels and electrolytic manganese anode slime has the advantages that the pineapple peels are used as reducing agent, the wastes are turned into valuable things and the method has environmental and economic dual benefits.

Description

Technical field: [0001] The invention relates to a method for resource utilization of pineapple peel and electrolytic manganese anode slime, which is especially suitable for leaching manganese and selenium in electrolytic manganese anode slime by using pineapple peel as a reducing agent in a sulfuric acid medium, and realizing precious metals such as lead, silver and tin The method of enrichment, selenium in the leach solution is recovered by iron-carbon micro-electrolysis. Background technique: [0002] Pineapple is one of the famous tropical fruits. my country's pineapple output is about 2 million tons, mainly distributed in Guangdong, Hainan, Yunnan, Guangxi, Fujian and Taiwan. At present, the main types of pineapple trade products are fresh (dried) pineapple, canned pineapple and pineapple juice. The deep processing of pineapple will produce a large amount of leftovers, that is, pineapple skin, which accounts for 50% to 60% of the weight of the whole fruit. Studies ha...

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Problems solved by technology

[0007] ②【Title】Research on the leaching of electrolytic manganese anode slime with sulfurous acid【Author】Li Yingfen【Institution】College of Chemistry and Chemical Engineering, Central South University 【Title】Master's thesis. The leaching method treats electrolytic manganese anode slime and separates manganese, lead and selenium. The two ore methods are difficult to recycle selenium and lead due to complex components. The sulfur dioxide method is fast and efficient. The leaching rate of manganese is over 90%, and the leaching rate of selenium is 80%. % or more, the lead content of the filter residue is about 20%, and the pilot test is carried out on it, and the lead content of the filter residue is about 15%-18%

Literature ② adopts the wet process to select pyrite and sulfur dioxide as the reducing agent to leach manganese and enrich selenium and lead. The two ore methods are difficult to recycle selenium because of the complex composition, and the amount of slag is large; the sulfur dioxide method SO 2 The utilization rate is low, and a large number of sulfide ions and dithionites are brought into the solution, which affects the product purity and electrolysis process

Patent ③ uses the method of reducing manganese anode slime at high temperature. The steam containing selenium and lead produced by high-temperature roasting is highly toxic, but this patent does not recycle it, and it is directly discharged, which is likely to cause serious environmental pollution.

Patent ④ mainly uses sodium hydroxide to oxidize and roast manganese anode slime, the process is long and complicated, and the use of a large amount of sodium hydroxide is easy to corrode equipment, and formaldehyde is easy to cause poisoning, which is not conducive to actual operation and production

[0011] To sum up, the processes reported in the existing literature generally only recycle the main components of manganese and lead, but do not realize the step-by-step extraction of other impurity elements, especially the selenium in manganese anode slime, which is expensive , has been in serious shortage in China, and is an essential additive in the electrolytic manganese system, and inorganic selenium is a highly toxic substance, which is easily discharged and polluted

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