公开(公告)号：US3968032A

公开(公告)日：1976-07-06

申请号：US435409

申请日：1974-01-22

申请人： Francisco Javier Sitges Menendez ,  Vicente Arregui Fernandez ,  Macario Quesada Quintana

发明人： Francisco Javier Sitges Menendez ,  Vicente Arregui Fernandez ,  Macario Quesada Quintana

IPC分类号： C22B11/00 ,  B03D1/02 ,  B03D1/06

CPC分类号： B03D1/06 ,  B03D1/02

摘要： A flotation process for recovering lead and silver values from electrolytic zinc residues is disclosed.BACKGROUND OF THE INVENTIONThe present invention relates to a process for reclaiming silver and lead by flotation in products containing oxidized lead such as lead sulfate. More particularly, the present flotation process is for recovering silver and lead contained in the residue from electrolytic zinc production using either zinc concentrates or complex concentrates as the raw material.By zinc concentrates we consider those commonly accepted as such, that is, those in which the zinc concentration is sufficiently high to allow their reclaiming by electrolysis.Complex concentrates are those obtained by bulk flotation of complex sulphide ores, those commonly called "middlings" in a selective flotation of same or other similar ones. Analysis of these concentrates gives values which usually vary according to the following figures : 10-45% Zn; 3-40% Pb; 0-25% Cu; 0-5,000 gr/m.t. Ag; 5-30% Fe.It is known that zinc can be obtained from zinc sulphide concentrates by roasting these concentrates to obtain a calcined product which contains oxidized zinc. It is also known that in the standard process for obtaining zinc by electrolysis, the zinc oxide is dissolved in an aqueous sulphuric acid solution. The zinc sulphate solution obtained is purified and subsequently electrolized to reclaim the zinc, at the same time as the oxygen liberated during electrolysis produces sulphuric acid which is used to dissolve more zinc oxide. This acid, known as "spent electrolyte" or "return acid" has a concentration which generally varies between 150-200 gr./1. of H.sub.2 SO.sub.4.During the roasting process both of the zinc concentrates and of the complex concentrates, the iron combines with the rest of the existing metals giving compounds, "ferrites", which generally agree to the formula of MeO.Fe.sub.2 O.sub.3, in which Me represents any of the metals accompanying the iron in the concentrates.The MeO.Fe.sub.2 O.sub.3 ferrites are insoluble in the aqueous sulphuric acid solution used in lixiviation of the zinc oxide, in standard conditions existing in lixiviation stages for reclaiming zinc by electrolysis. The greater the concentration in iron of the concentrated ore, the greater is the quantity of metals which become insoluble during roasting. Consequently, from the lixiviation stages a residue is obtained whose zinc content can range within very wide margins, we could say from 15 to 35%, according to whether the lixiviated material is standard zinc concentrate, or on the other hand whether it is a complex concentrate.There are several processes which have been proposed over the last few years for reclaiming zinc and the rest of the valuable metals contained in these residues. Some of them have gone no further than mere laboratory tests; others have found adequate industrial application. Such is the case covered by U.S. Pat. No. 3,434,798, granted on Mar. 25, 1969.In all the processes proposed, the solution of zinc and iron is accompanied by the simultaneous solution, and in high proportions, of other valuable elements, such as Cd, Cu, etc.In all the processes, there is a final insoluble residue containing a very high percentage of Pb and Ag, and other precious metals contained in the original concentrates. The final destination of this insoluble residue, from reclaiming zinc and other valuable metals from the residue of obtaining electrolytic zinc from zinc ore concentrates and complex concentrates, is, almost invariably, to be sent to a lead foundry or a shaft furnace. Until now no process by flotation has been known on an industrial scale designed to reclaim lead, silver and other noble metals from the final insoluble residues from reclaiming zinc or other metals.SUMMARY OF THE INVENTIONAccordingly, the aim of the present invention is to provide a process by means of which lead and silver can be reclaimed by flotation, from the residue obtained from the production of electrolytic zinc or other metals, using as raw material, either concentrates of the metal concerned, or complex concentrates of the metal in question, reaching highly satisfactory yields.In the applicants case, in whose laboratories and plant all the research and tests have been carried out, the two types of concentrates mentioned above were used in the electrolytic zinc plant as raw material.In both cases, after the lixiviation stage and of applying the residues obtained from this lixiviation stage, in the process disclosed in the afore-mentioned U.S. Patent No. 3,434,798, a final product is obtained whose normal analysis is as follows:Total Zn 1.49% As- 0.006% Mn- 0.34% Total Pb 18.00% Sb- 0.01 % Ni- 0.0005% Total Cd 0.011% Ge- 0.0005% Total Fe 3.00% Ag 650 gr./m.t. CaO = 15.85%; MgO = 1.45%; Total S- = 15.80% S-SO.sub.4 = 15.80; Insoluble R. = 4.68% These percentages can vary within very wide limits, always depending on the original composition of the concentrates.In this residue the lead is found almost entirely in the form of sulphate.The process proposed, according to the invention, is based on the fact that the silver compounds, in the form in which they come in said residues, and the lead sulphate can be reclaimed by flotation, when this takes place in a suitable medium and with an equally suitable technique.For the process of the invention, it is advisable and at times necessary, to remove the elements in solution in said residues before starting flotation.Flotation, according to the process proposed, can be done in one or two stages, therefore obtaining one or two concentrates, respectively.The flotation system chosen, in one or two stages, will depend on the metal content of the residues and basically on the Pb/Zn and Pb elemental S ratio, as well as the silver contained in these residues. It is therefore advisable to carry out flotation in two stages when the zinc and elemental sulphur are high compared with the lead in the residue to be treated. On the other hand, when the percentage of zinc and elemental sulphur is very low with respect to the lead, the process can be used in a single stage.When flotation is carried out in two stages, two concentrates are obtained, in the first of which a large part of the silver is reclaimed accompanied by elemental sulphur and zinc, whereas in the second concentrate, the lead sulphate is reclaimed and the rest of the silver.When flotation takes place in two stages, in that corresponding to reclaiming the silver, flotation is carried out preferably in an acid medium.The acidity level of this stage will influence decisively the quality of the silver concentrate, and even affect reclaiming the lead in the following stage.In this first stage, after the slurry has been prepared at a suitable percentage of solids, which although it can vary, generally will be from 20 to 25%, and after fixing the best acidity level, the slurry is taken to a tank or conditioner where the suitable reagents are added to obtain flotation of the silver, elemental sulphur and zinc compounds.The best level of acidity will range between a pH of 2 and 4.5.Although the acidity level can vary between very wide limits, regarding flotation of silver, this flotation can even be carried out in a neutral or alkaline medium, in order to obtain maximum separation of the lead, and silver, and subsequently the better flotation of the lead, it is necessary to fix the best level of acidity, which will range between a pH from 2 to 4.5.As a collector reagent, xanthates, dithiophosphates or others can be used, but preferably reagents should be used which do not collect the lead in the first stage of flotation.The addition of dispersants may also be useful, such as sodium silicate or others.A frothing reagent will also be used, if necessary, to produce sufficient foam for efficient flotation.The slurry flows from the conditioner tank to some flotation cells where the operation commonly known as "rougher" takes place.The foam of this "rougher" is recleaned afterwards several times, preferably between one and three stages.The residues of these recleaners, will normally be joined to the residues of the "rougher" operation, but they can also be added at the beginning of the "rougher" or even be removed with the final tailings of the treatment.The level of acidity in the recleaning influences the quality of the final silver concentrate, so it is advisable to keep the best acidity level mentioned above.The quality of this concentrate is very variable, and always depends not only on the silver content of the original slurry, but on the iron content and especially on the zinc and elemental sulphur contents of said slurry.With this concentrate, the classical operations are carried out of all floated products: decantation, filtration and drying.The dry product is subjected to calcination to enrich it in silver and zinc through the elemental sulphur coming away in the form of SO.sub.2, which can subsequently be used in other industrial processes.In calcination, fuel consumption is minimum, as it is only necessary to start combustion.The residues of the "rougher" cells, together with the residues of the recleaners, as the case may be, pass on to a conditioner where, by means of a sulphurizing agent, the lead sulphate is activated so that it can be collected by the collector reagents commonly used in mineral flotation.Sodium sulphide is used preferably as a sulphurizing agent.Dispersant reagents or specific depressors of the compounds accompanying the lead sulphate can be added in the conditioner or later in the "rougher" cells, although this is not generally necessary.The level of acidity of the slurry entering the conditioner where the activation is checked of the lead sulphate is of decisive importance in this activation, and should be kept at the afore-mentioned best acidity level. Otherwise lead sulphate reclaiming drops considerably, reaching such a point, when the acidity level is a long way from the optimum level, that this drop would clearly make this operation uneconomical.After sulphurizing, the slurry passes from the conditioner to some flotation cells where the collector and frothing reagents are added, if the latter are necessary to produce sufficient foam for efficient flotation.In these cells, a product commonly known as lead sulphate "rougher" is floated.Xanthates and/or dithiophosphates will preferably be used as collectors.As frothing agents, reagents of this type which have no collector properties should preferably be used.Both the collectors reagents and the frothing agents, when the latter are necessary, should be added preferably gradually, a small amount at a time.In some cases, the addition of ammonium sulphate is useful.The floated "rougher" product passes to other cells, where a product is again floated which is commonly called lead sulphate cleaner or recleaning.This cleaning or recleaning operation can be repeated several times. Usually from one to three times is sufficient.In these recleaning oerations, it is advisable to keep the best acidity level between the afore-mentioned margins.In the recleaning, sulphurizing agents can be added, as well as collector and dispersant reagents or specific depressors of the compounds accompanying the lead sulphate, although it will not be necessary.The residues of the "rougher" operation are the so-called tailings in flotation plants.The residues of the recleaner cells can be added again at the beginning of the "rougher" or at the beginning of another operation prior to recleaning, provided they are less than two, or all or some of them can be added to the tailings.Adding the recleaning residues to the sterile will usually be decided by the impurities of the "rougher" flotation product.If the "rougher" product has a high iron content, it is better to add the residues to the tailings, to obtain a good quality lead sulphate.The final lead sulphate product is the product floated in the last recleaner cells operation.The quality of this concentrate or final product varies depending, apart from the lead content of the original material concerned, on the other compounds which may impurify said concentrate.If in the original ore, the zinc content is low compared with its lead content, the product of the silver flotation, once calcined, can be added to the product of the lead sulphate flotation, thereby enriching in silver the lead sulphate and improving the lead yield.The residues of the first "rougher" stage, both in reclaiming silver and lead, can continue to another flotation stage, where the floated product, called "blends", is added at the head of the relevant "rougher" stage. The residues of this second flotation, which come from the silver "rougher" would pass to the conditioner where activation of the lead starts, whereas those which come from the lead "rougher" form sterile residues which are removed.As mentioned above, silver and lead flotation can be carried out together.In this case, the same process should be followed as disclosed for lead sulphate flotation.Normally, it is not advisable to float silver and lead sulphate compounds together, as small quantities of the sulphurizing agent in excess can cause great losses of silver.During the research period, it was possible to determine quite accurately the factors which to a greater or lesser extent influence both the work setup and the products obtained from flotation. It is clear that most of these factors depend on the composition of the residue sent to flotation which in turn likewise depends on both the composition of the original zinc concentrate, and the process followed in its treatment.We can speak of two types of products as extreme cases.a. Pb/Ag residues with low iron and zinc contents.b. Pb/Ag residues with high iron content.In some cases, when the iron content is high, most of this iron comes in the form of basic complex sulphate (jarosite).When the Pb/Ag residues have a high iron content, sometimes this iron can impurify the lead and silver concentrates.In this case, iron lixiviation increases the lead and silver concentration in the final products to acceptable values.An average balance obtained in an industrial plant following the process of the invention with two stages was as follows : % PRODUCTS WEIGHT % Pb Ag. gr/m.t. % Zn % Fe ______________________________________ Ag concentrate 5.5 14,300 30.2 2.3 Pb concentrate 55.5 900 3.6 3.2 Tailings 4.3 150 1.5 1.8 Feed 27.9 1,202 3.9 2.5 Distribution % % PRODUCTS WEIGHT % Pb Ag. gr/m.t. % Zn % Fe ______________________________________ Ag concentrate 5.0 1.00 59.45 38.70 4.66 Pb concentrate 46.0 91.46 34.42 42.45 59.61 Tailings 49.0 7.54 6.13 18.85 35.73 Feed 100.0 100.00 100.00 100.00 100.00 ______________________________________ The silver concentrate did not calcine.An average balance, when flotation was carried out in a single stage, is given below :ANALYSIS PRODUCTS % WEIGHT % Pb Ag. gr/m.t. % Zinc % Fe __________________________________________________________________________Ag and Pb concentrate 50.6 2,214 6.2 3.1 Tailings 4.3 150 1.5 1.8 FEED 27.9 1,202 3.9 2.5 Distribution % PRODUCTS % WEIGHT % Pb Ag. gr/m.t. % Zinc % Fe __________________________________________________________________________Ag and Pb concen- 51.0 92.46 93.87 81.15 64.27 trate Tailings 49.0 7.54 6.13 18.85 35.73 FEED 100.0 100.00 100.00 100.00 100.00 __________________________________________________________________________To enable the objects and features of the invention to be understood more easily, a more detailed description is given below thereof, referring to the attached drawings, in which a preferred form of embodiment is given by way of unlimited example:

摘要翻译： 公开了一种从电解锌残渣中回收铅和银的浮选工艺。

公开(公告)号：US3985857A

公开(公告)日：1976-10-12

申请号：US387191

申请日：1973-08-09

申请人： Francisco Javier Sitges Menendez ,  Vicente Arregui Fernandez

发明人： Francisco Javier Sitges Menendez ,  Vicente Arregui Fernandez

IPC分类号： C22B19/20 ,  C01B20060101 ,  C01G9/00 ,  C01G9/06 ,  C01G49/00 ,  C01G49/14 ,  C22B20060101 ,  C22B3/00 ,  C22B3/04 ,  C22B7/00 ,  C22B19/00 ,  C22B19/02 ,  C22B19/30 ,  C25C1/16 ,  C22B19/22

CPC分类号： C22B19/22 ,  Y02P10/234

摘要： The improvement in the process for recovering zinc from ferrites which includes treating electrolytic zinc plants residues with a sulfuric acid solution to dissolve the zinc and metals, a solution resulting which contains sulphates of zinc and the other dissolved metals. The undissolved residue is separated in a certain manner from the solution. The solids-free solution is neutralized in a second step with calcine or another neutralizing agent containing zinc until a certain acidity is reached so that the iron remaining in solution separates therefrom in the form of its complex basic sulfate. The solids are settled out and then sent to a neutralization step, which is part of the residue separation scheme, where they are used as seeds of crystals of complex basic sulfate of iron which helps to remove iron in the first neutralization step. This final solution is added to the normal circuit or process flow path of electrolytic zinc plants. Any Fe.sup.+.sup.+ existing or forming during the process is oxidized by MnO.sub.2.

摘要翻译： 从铁氧体中回收锌的方法的改进，其中包括用硫酸溶液处理电解锌工厂残留物以溶解锌和金属，产生含有硫酸锌和其它溶解金属的溶液。 未溶解的残余物以某种方式与溶液分离。 不含固体的溶液在第二步中用煅烧物或含锌的另一中和剂中和，直到达到一定的酸度，使得残留在溶液中的铁以其复合碱性硫酸盐的形式分离。 将固体沉淀出来，然后送入中和步骤，该中和步骤是残余物分离方案的一部分，其中它们用作在第一中和步骤中有助于除铁的复合碱式硫酸铁的晶体种子。 该最终解决方案被添加到电解锌厂的正常电路或工艺流程中。 在过程中存在或形成的任何Fe ++都被MnO2氧化。

公开(公告)号：US5531882A

公开(公告)日：1996-07-02

申请号：US535455

申请日：1995-09-28

申请人： Francisco Javier Sitges Menendez ,  Fernando Sitges Menendez ,  Francisco Alvarez Tamargo ,  Jose Maria Martinez Valdes

发明人： Francisco Javier Sitges Menendez ,  Fernando Sitges Menendez ,  Francisco Alvarez Tamargo ,  Jose Maria Martinez Valdes

IPC分类号： C25C7/02 ,  C25C7/06

CPC分类号： C25C7/06 ,  Y10S29/007 ,  Y10S29/067 ,  Y10S29/088 ,  Y10S29/098 ,  Y10T29/4528 ,  Y10T29/4544

摘要： A procedure and machine for cleaning the anodes of electrolytic tanks, said procedure comprising the operations of mechanically breaking the deposits on the surfaces of the anodes, detaching and separating the deposits, once broken, and then subjecting the plate of the anodes to a flattening operation. The procedure is carried out with a machine which includes at least one pair of cutting rollers (1), nozzles for supplying jets of water under pressure (2) situated above said rollers (1), two flattening plates (3) with flat opposing surfaces, and means of suspending and raising the anodes (13) between the rollers (1), nozzles (2) and plates (3). The plates (3) may be provided on their opposing surfaces with cutting grooves.

摘要翻译： 一种用于清洁电解池阳极的方法和机器，所述方法包括机械地破坏阳极表面上的沉积物，一旦断裂分离和分离沉积物的操作，然后使阳极板进行扁平化操作 。 该方法使用包括至少一对切割辊（1）的机器进行，用于在位于所述辊（1）上方的压力下提供水的喷嘴的喷嘴，具有平坦相对表面的两个平坦板（3） 以及在辊（1），喷嘴（2）和板（3）之间悬挂和升高阳极（13）的装置。 板（3）可以在其相对的表面上设置有切割凹槽。