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Phosphorus recovery from waste - methods review

100%
EN
According to sustainable development principles, searching for alternative phosphorus sources, especially possible ways of its recycling from waste, should be treated as a preferential problem of the phosphorus industry. The ways admitted as most important are:- phosphorus recovery from municipal and industrial sewage and from sewage sludge,- utilization of phosphorus from manure- management of waste from meat industryThe forecasts elaborated at the end of the last century, indicate that over 50% of the world phosphorus resources in use today will be depleted during the next 60 - 70 years. That fact contributes to increase of market prices of phosphorus products.This work presents possible directions for the recovery and management of sewage sludge, meat meal and manure as a phosphorus source for chemical industry.
EN
Sodium tripolyphosphate STPP is used in laundry detergent as a detergent "builder". The paper presents the chemical method of obtaining "heavy", i.e. with higher bulk density granulated sodium tripolyphosphate. The bulk density of sodium tripolyphosphate was increased by preparing a mixture of the dried sodium phosphates, the recycled subgrain of STPP and water in specific proportions and calcining this mixture for 1 hour at 400°C and 550°C (to obtain a proper STPP form) in the chamber kiln. This method allows producing the granular sodium tripolyphosphate with high bulk density (1.04-1.07 kg/dm3) and a high content of Form I or Form II, respectively.
EN
The influence of sewage sludge incineration temperature on the formed ash constitution was examined. The comparative extraction tests of two differently prepared ashes (laboratory and industrial) were carried out in order to verify if the parameters of sewage sludge incineration influence the extraction selectivity of phosphorus compounds. The laboratory ash (Alab) were prepared from sewage sludge incinerated at 950°C on a laboratory scale while the industrial ash (Aind) comes from thermal utilization system of the sewage sludge at the Gdynia Sewage Treatment Plant, which uses fluid-bed furnace incineration at 850 - 900°C. It was found that the temperature and the conditions of the sewage sludge incineration process have an effect on the usage properties of the formed ash. Despite the twofold lower Fe content in the industrial ash than that of the laboratory one, its content in extracts after phosphoric acid leaching is 4.7 times higher. The lower values of PO43- leaching degree from the industrial ash than the laboratory ash were observed, as well as a decrease of extraction productivity.
4
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From sewage sludge ash to calcium phosphate fertilizers

81%
EN
Our work presents the results of the research on the utilization of ashes after sewage sludge combustion comprising phosphorus recovery in the form of useful products. The investigations were divided into three parts: selecting the combustion parameters of sewage sludge, examining ash leaching with mineral acids (nitric and phosphoric) to high phosphorus selectivity assuring a low content of iron and heavy metals in the extracted solutions and precipitation of CaHPO4 .2H2O. Suitable temperature of a sewage sludge combustion enables selective extraction of phosphorus compounds from ash because of hematite phase forming, insoluble in mineral acids. The extracts from phosphoric acid leaching, where the extraction of phosphorus compounds was 96.1%, have very good properties for its further use as the initial solution for CaHPO4 .2H2O with 6% lime milk. The obtained product is characterized by high purity and phosphorus availability compatible even with the feed phosphate standard.
EN
Phosphogypsum is a noxious industrial waste contributing to global environmental and economic problems. This publication focuses above all on phosphogypsum resulting from the processing of apatite as a phosphorus bearing compound, since it contains considerable amounts of lanthanides due to its magma origin. The possibilities of its waste-free processing are large, however they require the application of suitable technologies, frequently expensive ones, and allowing for the individual characteristics of the given waste. The research works conducted so far confirm the possibility of applying phosphogypsum for the recovery of lanthanides, and the process enhances the removal of remaining impurities, thanks to which the purified calcium sulphate (gypsum) may find application for the production of construction materials.
EN
The new requirements that were placed on STPP, like high bulk density, the proper relation of Form I and Form II and suitable physicochemical properties, resulted in the development of the present production methods. The paper presents the research results on increasing the bulk density of STPP by a chemical method. In the introduced method the solid sodium phosphate from spray drying and sodium orthophosphate solution, after acid neutralization, were rubbed together. Such an operation changes the physicochemical properties of the dried sodium phosphate before calcining, which results in increasing the bulk density of STPP to a level of 0.80 kg/dm3. The dependence of STPP bulk density on process parameters such as: sodium orthophosphate solution to solid sodium phosphate mass ratio, temperature of dosed sodium orthophosphate solution, as well as the calcining temperature of mixtures were analysed.
EN
Bioleaching and biogenesis are the main outputs from a large group of environmental processes participating in the natural material cycle, used in raw materials processing. Bio-oxidation reactions are the main basis for bioleaching procedures, often participating in parallel leaching processes. During the leaching processes of polycomponent sulphide substrates, the factor of process selection also plays an important role, being in direct relation to the electric properties and galvanic effect occurring between the individual components of the leaching substrate. This work gives a summary of the results of a research focused on the possibilities of using biotechnological procedures for treatment of Slovak sulphide ores. The object of the research is extraction of valuable metals, undesirable admixtures and degradation of crystal lattice of sulphides for subsequent chemical leaching processing of precious metals. The results of experiments on the existence of biogenic processes in situ on waste dumps from exploitation containing residual sulphides are also presented. The processes result in acid mine drainage water generation. These waters are strongly mineralised (over 48 g/L) and of low pH; that is why they are very caustic. The arsenic content (2.558 mg/L) in outflowing waters from old mines is high and over the limits set by the law.
EN
Sodium tripolyphosphate - one of the condensed phosphates is an important ingredient in various types of cleaning substances and a food additive. The paper presents a comparison of different variants of STPP production with the application of the cumulative calculation method. The material balances of the processes were taken as the basis of the analysis. The method of the process analysis as shown in the cumulative calculation determines the influence of the emissions of dust and gas pollutions originating from a particular production process, as well as wastewater and solid wastes resulting from it, upon the natural environment. It was proved that the solution of the production STPP with the dry one-step method has the lowest impact on the environment among the three assessed solutions.
9
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Phosphorus cycle - possibilities for its rebuilding

62%
EN
The rebuilding of the phosphorus cycle can be performed with the use of both biotechnology and chemical technology. This paper presents a review of the phosphorus cycle and the different approaches that can be taken to the recovery of phosphorus from phosphate-rich waste. Critical issues in the phosphorus cycle are also discussed. Methods for the recovery of phosphorus form sewage sludge ash are widely explored and divided into two groups: wet extraction methods and thermochemical methods. Laboratory-scale methods are described, as well as proposed industrial technologies, with particular regard to the possibilities for their implementation in Poland. Phosphorus recovery methods from SSA (sewage sludge ash) in our country seems to be promising due to the increasing number of sewage sludge incineration plants, which could easily supply ash to future recovery installations. For the effective recovery of P from sewage sludge ash, it is essential to make the right choice in determining the appropriate method to use with respect to the particular properties of the ash composition available. A patented method of phosphorus recovery by acid extraction methods, developed by Cracow University of Technology, results in an efficiency of 80-96% for phosphorus recovery. 3000 to 4000 tons of phosphorus per year can be recycled and introduced back into the environment, that covers around 7% of the total amount of phosphorus ore imported into Poland between 2008 and 2009.
EN
The study presents a technology of sodium tripolyphosphate (STPP) production with the use of a dry, single-stage method. The reacting substrates (concentrated wet-process phosphoric acid - WPPA and solid Na2CO3 ) are mixed with a recycled final product (STPP) in a mixer, then a „quasi-dry” mixture is calcined in a rotary kiln. Thanks to that, some stages of a classic method of STPP production are eliminated: one of the two-stage neutralization of the phosphoric acid with sodium carbonate at temperature ~80°C, filtration of the neutralised solution and its evaporation, as well as the stage of drying a solution of mono- and di-sodium orthophosphate in a spray dryer. According to the presented technical and economical analysis, the costs of STPP production using a single-stage dry method can be 10% lower compared to the classic method.
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