During the electrolytic refining of copper what happens at the anode

I understand (more or less) that acidification of water helps in the dissociation of water into ions. Acids easily dissociate into ions in aqueous solution. So, accordingly, the hydrogen from the acid goes to the cathode and the hydrogen from the water makes a compound with the negative radical from the acid. In the process, oxygen is left alone and hence goes to the anode. I want to confirm whether this is the correct explanation. I have been trying to find out why is copper sulphate acidified during its electrolytic refining. I interpret that acidifying copper sulphate makes it dissociate easily into ions but I want to know what the exact process is. It doesn't seem to me that copper sulphate may behave in the same way as water does above. Please help. In general, I would like to understand the effect of decreasing or increasing pH on the process of electrolysis. I'd rather not put it in such terms. Dissociation of water is determined by the constant $\ce$), which in turn might or might not affect the reactions on one or both electrodes. As it happens, being too general prevents us from drawing more specific conclusions. You are right in that adding acid increases the concentration of dissociated ions in water, and that the hydrogen goes to the cathode but you have assumed too much with the oxygen part. In electrolysis/electroplating, the positive ions move towards the negative cathode and are reduced, and vice-versa, the negative ions move towards the positive anode and...

Unrefined copper is about 99 % pure. It contains traces of metals such as Fe, Zn, Ag, Au, and Pt. The purity can be increased to 99.95 % by electrolytic refining in a cell similar to that shown below. A thin sheet of high-purity Cu serves as the cathode. The anode is the impure Cu. The electrolyte is a solution of copper(II) sulfate. The Fe and Zn impurities are more easily oxidized than Cu. When current passes through the cell, these impurities go into solution from the anode, along with Cu. The ions all migrate toward the cathode, but Cu²⁺(aq) is more readily reduced than Fe²⁺(aq) or Zn²⁺(aq), so it is the only ion that plates out. The cathode increases in size, and the anode erodes away. The impurity ions remain in solution. Other impurities, such as Ag, Au, and Pt, are less easily oxidized than Cu. These remain in metallic form and fall to the bottom of the cell, forming “anode sludge” from which they can later be recovered.

In the electrolytic refining of copper, the impure copper is made from the anode in an electrolyte bath of copper sulfate, CuSO 4, and sulfuric acid H 2SO 4. The cathode is a sheet of very pure copper. As current is passed through the solution, positive copper ions, Cu 2+, in the solution are attracted to the negative cathode, where they take on electrons and deposit themselves as neutral copper atoms, thereby building up more and more pure copper on the cathode. Meanwhile, copper atoms in the positive anode give up electrons and dissolve into the electrolyte solution as copper ions. But the impurities in the anode do not go into solution because silver, gold and platinum atoms are not as easily oxidized (converted into positive ions) as copper is. So the silver, gold and platinum simply fall from the anode to the bottom of the tank, where they can be scraped up. Additional topics • • • Dysprosium to Electrophoresis - Electrophoretic Theory

• In Electrolytic refining, the impure metal is made to act as an anode. A strip of the same metal in pure form is used as a cathode. • They are put in a suitable electrolytic bath containing a soluble salt of the same metal. • The more basic metal remains in the solution and the less basic ones go to the anode mud. • Copper is refined using an electrolytic method. • Impurities from the blister copper deposit as anode mud which contains antimony, selenium, tellurium, silver, gold, and platinum; recovery of these elements may meet the cost of refining.

https://chem.libretexts.org/@app/auth/3/login?returnto=https%3A%2F%2Fchem.libretexts.org%2FBookshelves%2FInorganic_Chemistry%2FSupplemental_Modules_and_Websites_(Inorganic_Chemistry)%2FDescriptive_Chemistry%2FElements_Organized_by_Block%2F3_d-Block_Elements%2F1b_Properties_of_Transition_Metals%2FMetallurgy%2FThe_Extraction_of_Copper Expand/collapse global hierarchy • Home • Bookshelves • Inorganic Chemistry • Supplemental Modules and Websites (Inorganic Chemistry) • Descriptive Chemistry • Elements Organized by Block • d-Block Elements • Properties of Transition Metals • Metallurgy • The Extraction of Copper Expand/collapse global location Extracting copper from its ores The method used to extract copper from its ores depends on the nature of the ore. Sulfide ores such as chalcopyrite (\(CuFeS_2\)) are converted to copper by a different method from silicate, carbonate or sulfate ores. Chalcopyrite (also known as copper pyrites) and similar sulfide ores are the commonest ores of copper. The ores typically contain low percentages of copper and have to be concentrated before refining (e.g., via froth flotation). Figure 1: Chalcopyrite extracted from Zacatecas, Mexico. from Rob Lavinsky (iRocks.com) under a CC-BY-SA-3.0 license. The Process The concentrated ore is heated strongly with silicon dioxide (silica) and air or oxygen in a furnace or series of furnaces. • The copper(II) ions in the chalcopyrite are reduced to copper(I) sulfide (which is reduced further to copper metal...

The One of the world's oldest known copper mines, as opposed to usage of surface deposits, is at The [ dubious – Smelting [ ] Until the latter half of the 20th century, primary copper production). As of 2002, 80% of global primary copper production was from copper–iron–sulfur minerals, and the vast majority of these were treated by smelting. Copper was initially recovered from sulfide ores by directly smelting the ore in a furnace. Initial concentration techniques included hand-sorting In the twentieth century, most ores were concentrated before smelting. Smelting was initially undertaken using Copper smelting technology gave rise to the The modern Concentration (beneficiation) [ ] The average grade of copper ores in the 21st century is below 0.6% copper, with a proportion of economic ore minerals being less than 2% of the total volume of the ore rock. Thus, all mining operations, the In the usual case when it is primarily sulfide copper minerals (such as 2), the ore is treated by Froth flotation [ ] Secondary sulfides—those formed by Extraction processes for secondary copper sulfides and low-grade ores includes the process of heap bioleaching. Heap bioleaching presents a cost efficient extraction method that requires a less intensive energy input resulting in a higher profit. Generally, direct Some supergene sulfide deposits can be leached using a Supergene sulfide ores rich in native copper are refractory to treatment with sulfuric acid leaching on all practicable time s...