Cleaning Stage Research Articles

Identifying Key Environmental Indicators in the Assessment of the Proof-of-Concept in Pigment Production from the Marine Cyanobacterium Cyanobium sp.

Cyanobacteria have long attracted market interest as a source of natural compounds such as pigments with proven bioactivity (carotenoid and phycobiliproteins). The cultivation and extraction processes for such compounds have been developed at different levels, from laboratory trials to photobioreactors on a demonstration scale. Based on this experience, it is possible to propose how the different stages of the process can be improved based on environmental performance indicators. The Life Cycle Assessment (LCA) methodology allows to identify the hotspots that represent the greatest environmental impacts and to propose strategies to focus on those stages that can be improved. The general environmental indicators have been identified and the results showed that cyanobacteria cultivation has the greatest influence on environmental impact for all scales considered (from 20 L to 100 m3), which is attributed to the energy requirements. The main changes proposed to reduce the impact should focus on the stages of reactor cleaning, culture medium sterilisation and biomass drying. The implementation of these improvement alternatives can reduce the impact of the production and extraction processes by 85%. This work demonstrates how technological development must go hand in hand with impact assessment to make the best decisions in the overall process.

Masalah Kesehatan yang Dihadapi Praktisi Keperawatan Mandiri di Provinsi Lampung

The regulation of Nursing Practice increasingly encourages nurses to carry out independent practice legally. 447 practitioners in mid-2021 provide health care in Lampung, but there is no data about services available. This study aims to get an overview of the health problems served by practitioners. The research was held with a descriptive design. Data was collected by internet through a consecutive sampling of the population and gaining a sample of as many as 178 respondents. They were obtained and spread over 227 sub-districts throughout Lampung Province. The data is processed through cleaning and editing stages, equating terms, and then calculating the frequency. The results showed most cases are respiratory tract disorders (infections) with 167 cases. But non-communicable health problems become dominant such as gastrointestinal disorders and hypertension. Suggestions are given to professional organizations related to problem management in interprofessional collaboration, forming clinical pathways, and planning to increase understanding and application of standard diagnoses, outcomes, and interventions with a uniform nursing language in Indonesia.

Analysis of deposits in superheater tubes at coal-fired thermal power plants by Fourier IR spectroscopy

THE PURPOSE. Determination of the qualitative composition of deposits on the inner surface of the superheater tubes of the Aksuskaya GRES and CHPP stations of Aluminum Kazakhstan JSC located in the Republic of Kazakhstan. METHODS. The most modern method of analysis is IR spectrophotometry, which is based on the absorption of IR radiation. Sediment analysis was carried out on an infrared spectrophotometer with Fourier transform of Shimadzu IRAffinity-1S. The peculiarity and justification of using this device is based on the high throughput of optics. A complementary function is a combination with a dynamic digital adjustment system. The DLATGS detector is used as a powerful ceramic radiation source. This detector is highly sensitive and thermally stabilized. RESULTS. As a result of the analysis, it was found that the deposits on the inner surface are represented by metal corrosion products and heat-resistant humus substances. The latter easily pass into steam from boiler water (steam distillation) and settle on the surface of the tubes. Also, mineral substances and silicates are present as impurities, which also pass into steam in a small amount. CONCLUSION. As a result of the analysis of deposits in superheater tubes at the stations of Aksuskaya GRES and CHPP of Aluminum Kazakhstan JSC located in the Republic of Kazakhstan, it was found that corrosion processes are quite intense, therefore corrosion products predominate in the deposits. To reduce the internal wear of the tubes, it is necessary to adjust the VCR, analyze the reagents used, and perform a step-by-step analysis of the coolant at each stage of cleaning.

Characteristics of chemical composition and source apportionment of PM2.5 during a regional haze episode in the yangtze river delta, china

The source of PM2.5 varies at different stages of urban haze pollution. In addition, there is obvious regional transport of pollutants between urban agglomerations. PM2.5 and its major chemical compositions in a regional haze episode were measured continuously from 16 to 27 November 2018 in Nanjing, China. The types of primary sources resolved by principal component analysis (PCA) and positive matrix factorization (PMF) were similar, and the result of PMF was more refined. The average contribution of each source by PMF was: secondary nitrate (64.01%), secondary sulfate (11.62%), incomplete combustion (4.49%), sea salt (8.61%), biomass burning (6.90%), and crustal dust (4.37%). In different haze stages, the distribution characteristics of air pollutants differed. The concentrations of SO42-, NO3−, NH4+, and black carbon were the highest in the haze developing stage, which was 2.0, 3.1, 3.0, and 2.4 times, respectively, higher than that under clean conditions. The increment of NO3− dominated the development of haze, and the proportion of NO3− from haze generation to development increased by 4.05%. The concentration contributions of secondary nitrate, sea salt, and biomass burning were highest in haze development, secondary sulfate was highest in haze generation, and incomplete combustion was highest in haze dissipation, which was 3.5, 1.8, 3.3, 1.7, and 9.5 times higher than the clean stage, respectively. In the haze episode, the contribution of crustal dust was lower than in the clean stage. Potential source contribution function (PSCF) and concentration weighted trajectory (CWT) revealed that the major source area of air pollutants in Nanjing came from the southeast, and the northwest was the major impact area.

Use of fatty acids with an ethoxylated alcohol for apatite flotation from old fine-grained tailings

This work presents the results obtained during flotation of fine-grained apatite-bearing tailings provided from the Kovdor concentration plant in a laboratory cell and a pilot-scale column. Flotation studies were conducted on a sample containing >85 % particles passing 36 µm by using tall oil fatty acids in combination with polyoxyethylene cetyl ether (2 EO groups) as an alternative for nonylphenol ethoxylates. 45.5 % P2O5 recovery to a concentrate grade of 31.2 % P2O5 from 9.1 % P2O5 feed was achieved after rougher and one cleaner stage in a pilot-scale column using the mixed collector with phosphate modifier and starch as depressor.

Modernization of inertial-vacuum ash collector

Various variations of reducing the aerodynamic resistance of devices with a complex configuration of the flow path are considered. About 50% of power plants in the Russian Federation operate on coal, while two-stage cleaning is used in the ash collection process. Modern coarse ash collectors can achieve an efficiency of 55 – 80%, depending on the period of their work. It is advisable to reduce the number of purification stages by upgrading with the use of modern cleaning devices, which allow achieving high efficiency in cleaning a dusty flow and less subjecting this treatment complex to repair work. The inertial-vacuum ash collector (IVAC) provides trapping of a wide range of studied particles (1 – 100 microns) with an efficiency of up to 99%. This device was tested at the combined heat and power plant of the city of Omsk, and in addition to high efficiency, increased aerodynamic resistance was established. The aim of this work was to achieve an aerodynamic resistance of 660 Pa (resistance of the cyclone apparatus, so that the apparatus can be used as the first, and consequently as two stages of cleaning) while maintaining the efficiency of the apparatus. To achieve this goal, the IVAC uses the method of perforating holes along the divider for the subsequent decrease in speed in the confuser channel and a general decrease in resistance on the device. Perforation is carried out at three different heights, the distance between which is 1 meter. The study used the analysis of a numerical experiment in ANSYS CFX using a k-ε mathematical model (mass ash content 70 g/kg; One-way Coupling). Recommendations for further prospects for the study of the IVAC are proposed.

Microstructure and particle filtration behavior of multimodal filter media made of fibers of different shapes for automotive engine intake application

This article describes microstructure of needle-punched nonwoven filter media comprising polyester fibers of different cross-sectional shapes and reports on their dynamic particle filtration behavior both at clean and clogging stages. The multicomponent fibrous filter media were characterized by their mean fiber shapes which were related to those of the individual components weighted by the corresponding mass fractions. In such media, the fibers of different cross-sectional shapes produced a synergistic effect on the gravimetric filtration efficiency at the clean stage. The fractional filtration efficiency was quite accurately expressed as a sum of fractional filtration efficiencies of individual components weighted by their surface area fractions. The evolution of pressure drop was explained in light of drag theory, and the role of fiber shape in determining the drag coefficient was discussed. Overall, the multimodal fibrous filter media prepared with fibers of different cross-sectional shapes showed a high potential for automotive engine intake application.

Model pemeriksaan kesehatan berdasarkan komposisi tubuh terhadap peningkatan aktifitas fisik dan kualitas hidup lanjut usia

Background: Quality of Life is an assessment of the quality of life based on four domains, namely physical health, psychological conditions, social relationships, and the environment. The Healthy Living Community Movement (called GERMAS) focuses on physical activity, and regular health checks to improve quality of life, increase productivity, and lower health care costs.Objective: This study aims to see how effective the body composition health examination model is at increasing physical activity and quality of life in the elderly.Method: This quantitative research design is a quasi-experimental study conducted in Ulee Kareng District, Banda Aceh, in 2018. The sample, namely the elderly, was taken non-randomly, as many as 54 people. Data was collected by means of interviews and anthropometric measurements. The data is processed through the stages of editing, coding, tabulating, and cleaning. The analysis used a statistical with dependent t-test at 95% CI.Results: There is a difference in domain I (first), namely the physical health of the elderly, between the results of the pre-test (63.6 ± 15.248) and the results of the post-test (65.7 ± 14.872) with a p-value = 0.021 (p < 0.05). On the other hand, in domains II, III, and IV, there was no difference in the physical health of the elderly before and after the measurement (p > 0.05).Conclusion: Health examination through measuring body fitness affects the physical health of the elderly in domain I (first) but does not affect domains II, III, and IV.

Formulation and Evaluation of Herbal Shampoo

Abstract: The shampoo sector is probably the largest unit sale among the hair care products since shampoos are one of the cosmetic products used in daily life. Synthetic preservatives and detergents have sometimes been the cause of adverse effects among consumers. A more radical approach in reducing the synthetic ingredients is by incorporating natural extract whose functionality is comparable with their synthetic ingredients. A shampoo is a cleaning aid for the hair and is counted among the foremost beauty products. Today’s shampoo formulations are beyond the stage of pure cleaning of the hair. Additional benefits are expected, e.g., conditioning, smoothing of the hair surface, good health of hair, i.e., hair free of dandruff, dirt, grease and lice and, above all, its safety benefits are expected. As the scalp is one of the most absorbent part of the body, products applied to the scalp go directly to the blood, without being filtered in any way. In the scenario of changing food habits, stress level and dependent environment conditions, number of skin and hair disorders are encountered. This herbal shampoo was formulated using natural ingredient like Fenugreek seeds), Acacia concinna (shikakai), Sapindus mukorossi (reetha), Ocimum sanctum (tulsi), Aloe vera (aloe), Hibiscus rosa sinensis (china rose), Embelica officinalis (amla), Lawsonia inermis (henna),Citrus lemon (lemon), with proven efficacy of hair care preparation is prepared. The combination of several such ingredient of herbal origin has made it possible to secure highly effective dry powder shampoo. The formulation at laboratory scale was done and evaluated for number of parameters to ensure its safety and efficacy

Twitter User Sentiment Analysis Of TIX ID Applications Using Support Vector Machine Algorithm

The cinema is a place to watch movies using the big screen. Various comments on the TIX ID application service can be used to reference the company's evaluation material in assessing the level of service quality that has been provided, so that later the TIX ID application can be used optimally by application users and the company, as for the purpose of this study to find out responses and find out the sentiment analysis stage on twitter social media using the vector machine support algorithm for the TIX ID application. This algorithm is commonly used for text mining by going through the data collection stage, cleaning and labelling data stage, training and testing data sharing stage with 3 comparison scenarios, namely 70:30, 80:20, and 90:10 using 3 kernels, namely dot, radial, and polynomial, then through the text preprocessing stage, the TF-IDF word weighting stage, the data modeling stage, and the evaluation stage. The preprocessing stage consists of transform case, tokenize, and stopwords filters. The result of this study is that the support vector machine algorithm has an accuracy value of 74.17%. The research concludes that the support vector machine algorithm with a ratio of 80:20 training and testing data ratio scenario produces the highest accuracy.

The Role of Aerosol‐Radiation Interaction in the Meteorology Prediction at the Weather Scale in the Numerical Weather Prediction Model

AbstractThe current capabilities of the numerical weather prediction (NWP) model to simulate aerosol‐radiation interaction (ARI) impacts on weather prediction are still rarely considered compared with climate models. Here, the NWP model GRAPES_CUACE is used to evaluate the role of the ARI in meteorology prediction at the weather scale in China. The results show that the online calculation of ARI in the model can extensively improve the meteorology prediction accuracy involving temperature, wind, and pressure at most vertical levels in relatively clean, light, and heavy pollution stages. This improvement significantly occurs in the meteorology factors below 950 hPa prediction such as temperature at 2 m, 1,000, and 950 hPa, and mean sea level pressure, particularly in heavy pollution areas and stages. Unlike temperature, the improvement of ARI in the predicted wind at the height of the boundary layer is more significant than near‐surface. However, this improvement declines when the low‐cloud exists.

System for the Recognizing of Pigmented Skin Lesions with Fusion and Analysis of Heterogeneous Data Based on a Multimodal Neural Network.

Simple SummarySkin cancer is one of the most common cancers in humans. This study aims to create a system for recognizing pigmented skin lesions by analyzing heterogeneous data based on a multimodal neural network. Fusing patient statistics and multidimensional visual data allows for finding additional links between dermoscopic images and medical diagnostic results, significantly improving neural network classification accuracy. The use by specialists of the proposed system of neural network recognition of pigmented skin lesions will enhance the efficiency of diagnosis compared to visual diagnostic methods.Today, skin cancer is one of the most common malignant neoplasms in the human body. Diagnosis of pigmented lesions is challenging even for experienced dermatologists due to the wide range of morphological manifestations. Artificial intelligence technologies are capable of equaling and even surpassing the capabilities of a dermatologist in terms of efficiency. The main problem of implementing intellectual analysis systems is low accuracy. One of the possible ways to increase this indicator is using stages of preliminary processing of visual data and the use of heterogeneous data. The article proposes a multimodal neural network system for identifying pigmented skin lesions with a preliminary identification, and removing hair from dermatoscopic images. The novelty of the proposed system lies in the joint use of the stage of preliminary cleaning of hair structures and a multimodal neural network system for the analysis of heterogeneous data. The accuracy of pigmented skin lesions recognition in 10 diagnostically significant categories in the proposed system was 83.6%. The use of the proposed system by dermatologists as an auxiliary diagnostic method will minimize the impact of the human factor, assist in making medical decisions, and expand the possibilities of early detection of skin cancer.

Technological assessments on recent developments in fine and coarse particle flotation systems

• Froth flotation of fine and coarse particles is studied, focusing on cell designs. • Generating micro-bubbles, intensive turbulence, and high gas hold-up are advantages of intensified cells. • Scaling up/down procedures for the intensified cells are found unclear. • Positioning the optimum location of discussed cells in flotation circuits is found challenging. After more than a century applying flotation to the mining industry, two completely different strategies have been introduced for processing purposes. One is the classical approach viz. grinding ores to a certain extent (fine particles) and floating them via conventional mechanical and pneumatic cells i.e., Jameson, Imhoflot™ and Reflux™. This strategy continues because mines face declining cut-off grades, complex and poly-mineralized ores, and they are required to achieve an acceptable degree of mineral liberation. The other school of thought deals with coarse particle processes mainly owing to the low energy requirements, that includes SkimAir® flash, fluidized bed and HydroFloat™ cells. There is no study in the literature to comparatively present the recent developments of flotation apparatuses versus the conventional mechanical cells. To cover this knowledge gap in the literature, the present paper endeavors to critically evaluate these concepts from several points of view, including existing technological advancements, water and energy usage, kinetics, and circuit design. A brief introduction of advanced technologies, along with their applications is presented. The data from literature and case studies showed that the Jameson, Imhoflot™ and recently developed Reflux™ flotation cells can be very effective for recovering fine particles owing to their specific hydrodynamic designs, intensive energy dissipation rate and generation of micron-sized bubbles (100–700 µm). Very low (less than a few minutes) mean particle residence time, high gas-hold up (ca. 50–70 %), no agitation and high efficiency of particle-bubble collision were identified as their main advantages compared to traditional mechanical flotation cells. In addition to their common applications in cleaner stage, these cells were used in pre-flotation and scalping (producing final concentrate from the rougher feed) duties. Their main challenges were recognized as relatively unclear procedure on their scale up/down, optimization and simulation. The HydroFloat™ cell was indicated as a promising technology for recovering coarse particle fraction sizes by taking advantage of the fluidized-bed concept with plug-flow dispersion regime, high particle residence time, and limited cell turbulence. We finally concluded that fine particle flotation may remain as the main focus of re-processing tailings dams, while coarse particle treatment should be the focus of this century to reduce total energy consumptions.

VISUAL AND ELEMENTAL ANALYSIS OF NON-FIBRE INCLUSIONS IN TISSUE-PAPER FROM RECOVERED PAPER IN THE CONDITIONS OF THE ENTERPRISE OF SYKTYVKAR TISSUE GROUP OJSC

The article is devoted to solving an important scientific and technical task, improving the technology of production of tissue-paper. The study pays special attention to the problems related to the use of recovered paper, microscopic images of the surface of samples obtained from recovered paper sampling at various stages of the production of tissue-paper at the enterprise of Syktyvkar Tissue Group OJSC are presented. The main result of scientific research was a preliminary assessment of the study of the recovered paper stock preparation technology at the enterprise, for which the sampling from various stages of production were examined by a scanning electron microscope, which made it possible to visually assess the degree of cleaning of recovered paper from impurities from images of the microstructure of the surface of various scales. The chemical composition of the main additives was established by energy-dispersive X-ray spectral micro assay (EDX). Preliminary assessment of the nature of contamination, visual assessment of the microstructure of samples obtained from recovered paper stock from various stages of cleaning, allowed the engineers of the enterprise to evaluate the effectiveness of individual units of the stock preparation department for the production of tissue-paper. The obtained data will make it possible to specify the scientific and technical task and direct subsequent scientific work to improve the recovered paper stock preparation unit, which more requires perfection.

CFD-DEM Study of Bridging Mechanism of Particles in Ceramic Membrane Pores under Surface Filtration Conditions

In the surface filtration process with pores larger than the particle size, the formation of particle bridges plays a crucial role in the filter cake structure and the filtration efficiency throughout the filtration process. First, to understand the microscopic information required for the bridging mechanism, we use the two-way coupling of computational fluid dynamics (CFD)–discrete element method (DEM) to simulate the deposition characteristics of particles in the pores of ceramic membranes. Next, by dynamically observing the deposition morphology and bridging process of particles, the bridging mechanism was revealed at the level of a single hole. Then, we studied the influence of particle concentration and inlet velocity on the bridge erection process. The results show that the bridging function of particles runs through the clean filtration stage and the transition stage. Particle concentration and inlet flow rate have a crucial influence on the formation of particle bridges and filtration efficiency.

Chemical Cleaning of Magnetite Deposits on the Flow Mini-Channels of a Printed Circuit Heat Exchanger in an EDTA-Based Solution.

The dissolution behavior of magnetite deposited on flow mini-channel surfaces within a printed circuit heat exchanger (PCHE) and the corrosion behavior of a STS 316L PCHE material were investigated in an ethylendiaminetetraacetic acid (EDTA)-based chemical cleaning solution at 93 °C. The fouling in the PCHE was simulated using a water-steam circulation loop system. Most of the magnetite deposits were rapidly dissolved in the early stage of the circulation chemical cleaning. An empirical equation for estimating the dissolution percentage was derived as a function of cleaning time. The PCHE material showed excellent corrosion resistance during the chemical cleaning tests. These results indicate the fouling layers in the PCHEs can be removed efficiently by the chemical cleaning process without concern about base metal corrosion.

Cleaning of in-hospital flexible endoscopes: Limitations and challenges.

Objective: to analyze the cleaning process of gastroscopes, colonoscopes and duodenoscopes in eight in-hospital health services.Method: a cross-sectional study conducted with 22 endoscopes (eight gastroscopes, eight colonoscopes and six duodenoscopes), and microbiological analysis of 60 samples of air/water channels (all endoscopes) and elevator (duodenoscopes), in addition to protein testing. Descriptive statistics with calculation of frequencies and central tendency measures was used in data analysis.Results: the processing of 22 endoscopes was monitored with microbiological analysis for 60 channels. In the pre-cleaning procedure, in 82.3% (14/17) of the devices, gauze was used in cleaning the insertion tube. Incomplete immersion of the endoscope in detergent solution occurred in 72.3% (17/22) of the cases, and in 63.6% (14/22) there was no standardization of filling-in of the channels. Friction of the biopsy channel was not performed in 13.6% (3/22) of the devices. In the microbiological analysis, 25% (7/32) of the samples from the stored endoscopes were positive for microbial growth (from 2x101 to 9.5x104 CFU/mL), while after processing, contamination was 32% (9/28). Protein residues in the elevator channel were detected in 33% of duodenoscopes.Conclusion: the results indicate important gaps in the stages of pre-cleaning and cleaning of endoscopes that, associated with presence of protein residues and growth of microorganisms of epidemiological importance, indicate limitations in safety of the processing procedures, which can compromise the disinfection processes and, consequently, their safe use among patients subjected to such tests.

Dimethyl ether production from rice straw: process modelling and simulation

Climate change has been a worldwide concern for recently centuries, and exploitation as well as use of fossil fuels dominantly contribute towards the environmental degradation. Several types of alternative energy resources have been taken into account and evaluated in order to find out viable options for the future, and dimethyl ether (DME) is one of those that are worth serious consideration. In this research, a continuous DME production process was developed and simulated using Aspen HYSYSTM. Rice straw, the most popular type of biomass in Vietnam, was chosen to be feedstock for the fuel production. The proposed process consists of five major sections: rice straw pretreatment and gasification for synthesis gas (syngas) generation using a circulating fluidized bed gasifier (CFBG); water-gas shift reaction (WGSR) for H2/CO ratio adjustment in syngas; gas cleaning stage where H2O, H2S and CO2 are removed; DME synthesis via direct production pathway; and DME purification for separation of main product and recycling of methanol. The simulation results indicated a production capacity of approximately 2,307 kg of DME per hour and chemical energy conversion efficiency (ηDME) from biomass into DME of 75%. In addition to that finding, an investigation into the gasifier's operating parameters was conducted for the purpose of maximizing amount of DME generated. From investigation data obtained, the operating temperature of CFBG, steam to biomass (S/B) ratio, and equivalence ratio (ER) that fulfilled such an aim were concluded to be 900oC, 0.27, and 0.32, respectively. This work offers a novel option for utilization of massive availablity of agricultural residues in Vietnam by turning it into a type of promising fuel, and therefore lessen environmental burden as well as may develop Vietnam's energy market.

Validation of the expert methodology «Detection of condensed traces of the gunshot residue containing heavy metal compounds on various objects by scanning electron microscopy and X-ray microanalysis»

We present and discuss the results of the validation of a forensic qualitative testing technique which consists in the detection of condensed traces of the gunshot residue (GSR) in the form of individual microparticles on the objects under study and their identification by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) using a scanning electron microscope Mira III (Tescan, Czech Republic) equipped with a system of X-ray microanalysis INCA GSR 450 (Oxford Nanoanalysis, Great Britain). The procedure for detecting GSR particles containing heavy metal compounds, systems of their classification and interpretation of test results are described. The suitability of the methodology for solving forensic problems has been confirmed. The validation procedure consists in assessing the reliability by comparing the test results obtained by experts (A and B) in two laboratories at different times using the same device, and in confirming the competence of experts proceeding from the results of blind tests. A standard sample ENFSI GSR PT 2018 A-03-07 is used. Each of the experts determined the number of particles classified as GSR present in control samples taken in a ballistic laboratory during a full-scale experiment: from the hands of the shooter; from the hands of a person who did not shoot; without microparticles (clean stage of an electron microscope). The reliability of the technique is characterized by the index (probability) of correct results of detecting GSR particles in the standard sample of at least 95.8% and by a small proportion of false results (no more than 5.4%). The competence of the experts is proved by the consistent results of «blind» testing of control full-scale samples, containing and not containing GSR particles obtained in different laboratories. The results of the validation indicate the suitability of the method for obtaining reliable and valid information about the presence of GSR particles on the objects under study.

The Separation of Carbonaceous Matter from Refractory Gold Ore Using Multi-Stage Flotation: A Case Study

As a pre-treatment method of refractory gold ore, carbonaceous matter (C-matter) flotation was investigated with multi-stage flotation by rougher, scavenger, and cleaner stages. Different dosages of kerosene and MIBC (4-Methyl-2-pentanol) were applied and the optimum dosage was selected by testing in each flotation stage. With the combination of each stage, four circuit designs were suggested, which were a single-stage rougher flotation (R), rougher-scavenger flotation (R+S), rougher-scavenger-scavenger cleaner flotation (R+S+SC), and rougher-rougher cleaner-scavenger-scavenger cleaner flotations (R+S+RC+SC). The results indicated that the scavenger flotation increased C-matter recovery but reduced C-matter grade compared with single-stage rougher flotation. Cleaning of the scavenger flotation concentrate improved C-matter grade significantly, but reduced recovery slightly. Cleaning of the rougher flotation concentrate achieved overall improved selectivity in flotation. A combination of rougher-scavenger flotation followed by cleaning of both concentrates (R+S+RC+SC) resulted in 73% C-matter recovery and a combined cleaner concentrate grade of 4%; the final tailings C-matter grade was 0.9%, where the C-matter remaining in the tailings was locked, and fine grained. The results demonstrate the need for the multi-stage flotation of C-matter from refractory gold ore to achieve selective separation and suggested the potential of C-matter flotation as the pre-treatment for efficient gold production.